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Background: Ambient air pollution has become a challenging global health issue since industrialization, especially affecting respiratory diseases. However, the causal link between air pollution and allergic respiratory diseases (ARDs) remains unclear due to confounding factors in conventional epidemiological studies across different populations. Thus, we aimed to clarify the causal associations between air pollution and ARDs in European and East Asian populations using Mendelian randomization (MR)., Methods: MR utilizes genetic variants and provides a satisfactory level of causal evidence. Genetic data for exposures (PM 2.5 , PM 2.5 absorbance, PM 10 , PM coarse , NO 2 and NO x ) and outcomes (allergic rhinitis, chronic rhinosinusitis, asthma, and obesity related asthma) were obtained from genome-wide association studies. Instrumental variables were strictly filtered based on core assumptions. Two-sample MR and sensitivity analyses were conducted separately for European and East Asian populations., Results: PM coarse was causally associated with an increased risk of chronic rhinosinusitis (OR = 1.588 [1.002-2.518]; p = 0.049) and obesity related asthma (OR = 1.956 [1.012-3.780]; p = 0.046) in European population, and PM 10 was associated with a decreased risk of allergic rhinitis in East Asian population (OR = 0.882 [0.798-0.974]; p = 0.013). No heterogeneity or pleiotropy was detected in any significant causal association., Conclusion: Our findings indicate that ambient air pollution has opposite impacts on the etiology of ARDs in European and East Asian populations, which provides evidence for decisions on public policies and suggests that different responses to environmental factors such as air pollution may contribute to racial heterogeneity of ARDs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Prior studies reported excess rates (ERs) of cardiorespiratory events associated with short-term increases in PM 2.5 concentrations, despite implementation of pollution-control policies. In 2017, Federal Tier 3 light-duty vehicle regulations began, and to-date there have been no assessments of population health effects of the policy. Using the NYS Statewide Planning and Research Cooperative System (SPARCS) database, we obtained hospitalizations and ED visits with a principal diagnosis of asthma or chronic obstructive pulmonary disease (COPD) for residents living within 15 miles of six urban PM 2.5 monitoring sites in NYS (2014-2019). We used a time-stratified case-crossover design and conditional logistic regression (adjusting for ambient temperature, relative humidity, and weekday) to estimate associations between PM 2.5 , POC (primary organic carbon), SOC (secondary organic carbon), and rates of respiratory disease hospitalizations and emergency department (ED) visits from 2014 to 2019. We evaluated demographic disparities in these relative rates and compared changes in ERs before (2014-2016) and after Tier 3 implementation (2017-2019). Each interquartile range increase in PM 2.5 was associated with increased ERs of asthma or COPD hospitalizations and ED visits in the previous 7 days (ERs ranged from 1.1%-3.1%). Interquartile range increases in POC were associated with increased rates of asthma ED visits (lag days 0-6: ER = 2.1%, 95% CI = 0.7%, 3.6%). Unexpectedly, the ERs of asthma admission and ED visits associated with PM 2.5 , POC, and SOC were higher during 2017-2019 (after Tier 3) than 2014-2016 (before Tier-3). Chronic obstructive pulmonary disease analyses showed similar patterns. Excess Rates were higher in children (<18 years; asthma) and seniors (≥65 years; COPD), and Black, Hispanic, and NYC residents. In summary, unanticipated increases in asthma and COPD ERs after Tier-3 implementation were observed, and demographic disparities in asthma/COPD and PM2.5, POC, and SOC associations were also observed. Future work should confirm findings and investigate triggering of respiratory events by source-specific PM., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The discriminatory and racist policy of historical redlining in the United States during the 1930s played a role in perpetuating contemporary environmental health disparities., Objective: Our objectives were to determine associations between home and school pollutant exposure (fine particulate matter [PM 2.5 ], NO 2 ) and respiratory outcomes (Composite Asthma Severity Index, lung function) among school-aged children with asthma and examine whether associations differed between children who resided and/or attended school in historically redlined compared to non-redlined neighborhoods., Methods: Children ages 6 to 17 with moderate-to-severe asthma (N = 240) from 9 US cities were included. Combined home and school exposure to PM 2.5 and NO 2 was calculated based on geospatially assessed monthly averaged outdoor pollutant concentrations. Repeated measures of Composite Asthma Severity Index and lung function were collected., Results: Overall, 37.5% of children resided and/or attended schools in historically redlined neighborhoods. Children in historically redlined neighborhoods had greater exposure to NO 2 (median: 15.4 vs 12.1 parts per billion) and closer distance to a highway (median: 0.86 vs 1.23 km), compared to those in non-redlined neighborhoods (P < .01). Overall, PM 2.5 was not associated with asthma severity or lung function. However, among children in redlined neighborhoods, higher PM 2.5 was associated with worse asthma severity (P < .005). No association was observed between pollutants and lung function or asthma severity among children in non-redlined neighborhoods (P > .005)., Conclusions: Our findings highlight the significance of historical redlining and current environmental health disparities among school-aged children with asthma, specifically, the environmental injustice of PM 2.5 exposure and its associations with respiratory health., Competing Interests: Disclosure statement Supported by the National Institutes of Health (NIH-K01HL140216), Robert Wood Johnson Foundation, and Amos Medical Faculty Development Award. This project has been funded in whole or in part with federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), National Center for Advancing Translational Sciences (NCATS), and Department of Health and Human Services under contract numbers 1UM1AI114271-01, UM2AI117870, 5UM1AI114271, NCATS/NIH UL1TR001079, NCATS/NIH 1UL1TR001430, NCATS/NIH UL1TR001873, NCATS/NIH UL1TR002345, UL1TRG01422, NIH/NCATS Colorado CTSA UL1 TR002535, NCATS/NIH UL1TR001876, and NIH/CTSA 5UL1TR001425-03. Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest., (Copyright © 2024 American Academy of Allergy, Asthma & Immunology. All rights reserved.)

Evidence on the link of long-term exposure to ozone (O 3 ) with childhood asthma, rhinitis, conjunctivitis and eczema is inconclusive. We did a population-based cross-sectional survey, including 177,888 children from 173 primary and middle schools in 14 Chinese cities. A satellite-based spatiotemporal model was employed to assess four-year average O 3 exposure at both residential and school locations. Information on asthma, allergic rhinitis, eczema and conjunctivitis was collected by a standard questionnaire developed by the American Thoracic Society. We used generalized non-linear and linear mixed models to test the associations. We observed linear exposure-response associations between O 3 and all outcomes. The odds ratios of doctor-diagnosed asthma, rhinitis, eczema, and conjunctivitis associated with per interquartile increment in home-school O 3 concentration were 1.31 (95 % confidence interval [CI]: 1.28, 1.34), 1.25 (95 %CI: 1.23, 1.28), 1.19 (95 %CI: 1.16, 1.21), and 1.28 (95 %CI: 1.21, 1.34), respectively. Similar associations were observed for asthma-related outcomes including current asthma, wheeze, current wheeze, persistent phlegm, and persistent cough. Moreover, stronger associations were observed among children who were aged > 12 years, physically inactive, and exposed to higher temperature. In conclusion, long-term O 3 exposure was associated with higher risks of asthma, allergic rhinitis, conjunctivitis and eczema in children., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Rationale: The benefits of improved air quality on asthma remain understudied. Objectives: Our aim was to investigate associations of changes in ambient air pollution with incident asthma from school age until young adulthood in an area with mostly low air pollution levels. Methods: Participants in the BAMSE (Swedish abbreviation for Children, Allergy, Environment, Stockholm, Epidemiology) birth cohort from Stockholm without asthma before the 8-year follow-up were included ( N  = 2,371). We estimated the association of change in individual-level air pollutant exposure (particulate matter with an aerodynamic diameter ≤ 2.5 μm [PM 2.5 ] and ≤ 10 μm [PM 10 ], black carbon [BC], and nitrogen oxides [NO x ]) from the first year of life to the 8-year follow-up with asthma incidence from the 8-year until the 24-year follow-up. Multipollutant trajectories were identified using the group-based multivariate trajectory model. We also used parametric G-computation to quantify the asthma incidence under different hypothetical interventions regarding air pollution levels. Results: Air pollution levels at residency decreased during the period, with median reductions of 5.6% for PM 2.5 , 3.1% for PM 10 , 5.9% for BC, and 26.8% for NO x . A total of 395 incident asthma cases were identified from the 8-year until the 24-year follow-up. The odds ratio for asthma was 0.89 (95% confidence interval [CI], 0.80-0.99) for each interquartile range reduction in PM 2.5 (equal to 8.1% reduction). Associations appeared less clear for PM 10 , BC, and NO x . Five multipollutant trajectories were identified; the largest reduction trajectory displayed the lowest odds of asthma (odds ratio, 0.55; 95% CI, 0.31-0.98) compared with the lowest reduction trajectory. If the PM 2.5 exposure had not declined up to the 8-year follow-up, the hypothetical asthma incidence was estimated to have been 10.9% higher (95% CI, 0.8-20.8%). Conclusions: A decrease in PM 2.5 levels during childhood was associated with a lower risk of incident asthma from school age to young adulthood in an area with relatively low air pollution levels, suggesting broad respiratory health benefits from improved air quality.

Introduction: Exposure to ambient air pollution from combustion-source emissions contributes to the prevalence of asthma, but the role of early-life exposure in asthma development is not well understood. The objective was to examine the effects of early-life exposure to multiple specific ambient air pollutants on incidence and prevalence of asthma and to determine the mechanistic basis for these effects., Methods: The study included all live-born singletons in Denmark during 1998-2016 (N = 1,060,154), participants in the Danish National Birth Cohort (DNBC 3 , N = 22,084), and participants in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC, N = 803). We modeled the concentrations of particulate matter ≤2.5 and ≤10 μm in aerodynamic diameter (PM 2.5 and PM 10 ), PM-related elemental carbon (EC), organic carbon (OC), sulfate (SO 4 2- ), nitrate (NO 3 - ), ammonium (NH 4 + ), secondary organic aerosols (SOA), and sea salt as well as nitrogen dioxide (NO 2 ), nitrogen oxides (NO x ), sulfur dioxide (SO 2 ), and ozone (O 3 ) - from all sources. Prenatal and postnatal time-weighted mean exposures were calculated for all residential addresses., We defined asthma incidence as the first registered asthma diagnosis for all and used parental recall at child aged 7 to determine the prevalence of doctor-diagnosed asthma ever and active asthma for the DNBC participants. For the COPSAC participants, we analyzed inflammatory markers in blood collected at 6 months of age; at 6 years of age, we analyzed nasal epithelial deoxyribonucleic acid (DNA) methylation, gene expression, immune mediators, and forced expiratory volume in 1 second (FEV 1 )., Cox proportional hazard models were fitted with fixed prenatal means and time-varying running annual means of a year before the event for the postnatal follow-up period for asthma incidence. Logistic regression models with cluster-robust standard errors and generalized estimating equations for dependence between women being included more than once were used for asthma prevalence. Mixed-effect linear regression models with random intercept for cohort were used to examine changes in lung function, and linear regression models were used to examine changes in biomarkers., Results: The prenatal mean and interquartile range (IQR) concentrations of PM 2.5 and NO 2 were 10.5 (2.4) and 17.5 (8.7) μg/m 3 . In the nationwide study the risk of asthma incidence increased with increasing prenatal exposure to all pollutants except for O 3 and sea salt. An IQR increase in prenatal exposure was associated with an adjusted hazard ratio (HR) and 95% confidence interval (CI) of 1.06 (95% CI: 1.04-1.08) for PM 2.5 and 1.04 (1.02-1.05) for NO 2 . The corresponding estimates for postnatal exposures were 1.08 (1.05-1.10) and 1.02 (1.01-1.04), respectively., In the DNBC participants, the asthma incidence results from models further adjusted with cohort-specific covariates were similar to models adjusted for register-based covariates only. Prenatal exposure to PM 2.5 , PM 10 , NO 2 , NO x , EC, SO 4 2- , and sea salt were weakly associated with elevated risk for asthma incidence. There was no evidence of associations with asthma prevalence., For the COPSAC children, an IQR of PM 2.5 and of NH 4 + was each associated with a 2%-3% (95% CI: 1%-5%) reduction in mean FEV 1 , consistently for prenatal and postnatal exposures. Prenatal exposure to PM and NO 2 was associated with immunological changes in blood and the airways but not with DNA methylation or gene expression changes., Conclusions: The results of these studies strengthen the evidence that long-term exposure to ambient air pollution contributes to the development of asthma in early life through an altered immune profile, even at these relatively low concentrations., (© 2024 Health Effects Institute. All rights reserved.)

The association of air pollution and greenspace with respiratory pathogen acquisition and respiratory health was investigated in a community-based birth-cohort of 158 Australian children. Weekly nasal swabs and daily symptom-diaries were collected for 2-years, with annual reviews from ages 3-7-years. Annual exposure to fine-particulate-matter (PM 2.5 ), nitrogen-dioxide (NO 2 ), and normalised-difference-vegetation-index (NDVI) was estimated for pregnancy and the first 2-years-of-life. We examined rhinovirus, any respiratory virus, Streptococcus pneumoniae, Moraxella catarrhalis , and Haemophilus influenzae detections in the first 3-months-of-life, age at initial pathogen detection, wheezing in the first 2-years, and asthma at ages 5-7-years. Our findings suggest that higher NDVI was associated with fewer viral and M. catarrhalis detections in the first 3-months, while increased PM 2.5 and NO 2 were linked to earlier symptomatic rhinovirus and H. influenzae detections, respectively. However, no associations were observed with wheezing or asthma. Early-life exposure to air pollution and greenspace may influence early-life respiratory pathogen acquisition and illness.  .

Respiratory virus infections are related to over 80% of childhood asthma exacerbations. They enhance pro-inflammatory mediator release, especially for sensitized individuals exposed to pollens/molds. Using a time-series study design, we investigated possible effect modification by respiratory virus infections of the associations between aeroallergens/PM 2.5 and asthma exacerbation rates. Outpatient, emergency department (ED), and inpatient visits for asthma exacerbation among children with asthma (28,540/24,444 [warm/cold season]), as well as viral infection counts were obtained from electronic health records of the Children's Hospital of Philadelphia from 2011 to 2016. Rate ratios (RRs, 90th percentile vs. 0) for late-season grass pollen were 1.00 (0.85-1.17), 1.04 (0.95-1.15), and 1.12 (0.96-1.32), respectively, for respiratory syncytial virus (RSV) counts within each tertile. However, similar trends were not observed for weed pollens/molds or PM 2.5 . Overall, our study provides little evidence supporting effect modification by respiratory viral infections.

Objectives: This study aims to assess the specific PM 2.5 -bound metallic elements that contribute to asthma emergency department visits by using a case-crossover study design., Methods: This study analyzed data from 11,410 asthma emergency department visits as case group and 22,820 non-asthma onset dates occurring one week and two weeks preceding the case day as controls from 2017 to 2020. PM 2.5 monitoring data and 35 PM. 2.5 -bound metallic elements from six different regions in Taiwan were collected. Conditional logistic regression models were used to assess the relationship between asthma and PM 2.5 -bound metallic elements., Results: Our investigation revealed a statistically significant risk of asthma emergency department visits associated with PM 2.5 exposure at lag 0, 1, 2, and 3 during autumn. Additionally, PM 2.5 -bound hafnium (Hf), thallium (Tl), rubidium (Rb), and aluminum (Al) exhibited a consistently significant positive correlation with asthma emergency department visits at lags 1, 2, and 3. In stratified analyses by area, age, and sex, PM 2.5 -bound Hf showed a significant and consistent correlation., Conclusions: This study provides evidence of PM 2.5 -bound metallic elements effects in asthma exacerbations, particularly for Hf. It emphasizes the importance of understanding the origins of these metallic elements and pursuing emission reductions to mitigate regional health risks., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Wei-Te Wu reports administrative support was provided by Department of Atmospheric Environment, Ministry of Environment, Executive Yuan, Taiwan. Wei-Te Wu reports administrative support was provided by Health and Welfare Data Science Center, Ministry of Health and Welfare, Executive Yuan, Taiwan. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The joint effect of air pollutants at relatively low levels requires further investigation. Here, a database study was performed to evaluate the effects of exposure to mixtures of air pollutants during pregnancy, infancy, and childhood on childhood persistent asthma. We used the Japan Medical Data Center database, which provides access to family linkages and healthcare provider addresses, and included child-mother dyads in which the child was born between January 2010 and January 2017. The exposure of interest was ground-level air pollutants, and the primary outcome was childhood persistent asthma at 45 years of age, as defined based on outpatient and inpatient asthma disease codes and/or asthma medication dispensing claims. The weighted quantile sum (WQS) regression was used to evaluate the effects of air pollutant mixtures on 52,526 child-mother dyads from 1149 of 1907 municipalities (60.3 %) in Japan. The WQS regression models showed that with every 10th percentile increase in the WQS index, ground-level air pollutants during pregnancy, infancy, and childhood increased the risk of childhood persistent asthma by an odds ratio of 1.04 (95 % CI: 1.02-1.05; p<0.001), 1.02 (95 % CI: 1.01-1.03; p<0.001), and 1.03 (95 % CI: 1.01-1.04; p<0.001), respectively. Moreover, particulate matter with an aerodynamic diameter ≤ 2.5 µm was assigned the highest weight across all three exposure periods. Relatively high weights were assigned to suspended particulate matter and photochemical oxidants during pregnancy, carbon monoxide during infancy, and photochemical oxidants during childhood. Our study showed that a mixture of low-level air pollutants has a detrimental association with childhood persistent asthma., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Akihiro Shiroshita reports financial support was provided by the Japanese Respiratory Society Research Grants Program and Japanese Respiratory Foundation Grant. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Previous studies of air pollution and respiratory disease often relied on aggregated or lagged acute respiratory disease outcome measures, such as emergency department (ED) visits or hospitalizations, which may lack temporal and spatial resolution. This study investigated the association between daily air pollution exposure and respiratory symptoms among participants with asthma and chronic obstructive pulmonary disease (COPD), using a unique dataset passively collected by digital sensors monitoring inhaled medication use. The aggregated dataset comprised 456,779 short-acting beta-agonist (SABA) puffs across 3,386 people with asthma or COPD, between 2012 and 2019, across the state of California. Each rescue use was assigned space-time air pollution values of nitrogen dioxide (NO 2 ), fine particulate matter with diameter ≤ 2.5 µm (PM 2.5 ) and ozone (O 3 ), derived from highly spatially resolved air pollution surfaces generated for the state of California. Statistical analyses were conducted using linear mixed models and random forest machine learning. Results indicate that daily air pollution exposure is positively associated with an increase in daily SABA use, for individual pollutants and simultaneous exposure to multiple pollutants. The advanced linear mixed model found that a 10-ppb increase in NO 2 , a 10 μg m -3 increase in PM 2.5 , and a 30-ppb increase in O 3 were respectively associated with incidence rate ratios of SABA use of 1.025 (95 % CI: 1.013-1.038), 1.054 (95 % CI: 1.041-1.068), and 1.161 (95 % CI: 1.127-1.233), equivalent to a respective 2.5 %, 5.4 % and 16 % increase in SABA puffs over the mean. The random forest machine learning approach showed similar results. This study highlights the potential of digital health sensors to provide valuable insights into the daily health impacts of environmental exposures, offering a novel approach to epidemiological research that goes beyond residential address. Further investigation is warranted to explore potential causal relationships and to inform public health strategies for respiratory disease management., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: All co-authors affirm the absence of any conflict of interest related to this research, with the exception of Meredith Barrett and Vy Vuong, who are employees of ResMed (to which Propeller Health is affiliated) and receive salary and stock., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The association between long-term exposure to ozone (O 3 ) and adult-onset asthma (AOA) remains inconclusive, and analysis of causality is lacking., Objectives: To examine the causal association between long-term O 3 exposure and AOA., Methods: A prospective cohort study of 362,098 participants was conducted using the UK Biobank study. Incident cases of AOA were identified using health administrative data of the National Health Services. O 3 exposure at participants' residential addresses was estimated by a spatio-temporal model. Instrumental variable (IV) modelling was used to analyze the causal association between O 3 exposure and AOA, by incorporating wind speed and planetary boundary layer height as IVs into time-dependent Cox model. Negative control outcome (accidental injury) was also used to additionally evaluate unmeasured confounding., Results: During a mean follow-up of 11.38 years, a total of 10,973 incident AOA cases were identified. A U-shaped concentration-response relationship was observed between O 3 exposure and AOA in the traditional Cox models with HR of 0.916 (95% CI: 0.888, 0.945) for O 3 at low levels (<38.17 ppb), and 1.204 (95% CI: 1.168, 1.242) for O 3 at high levels (≥38.17 ppb). However, in the IV analysis we only found a statistically significant association between high-level O 3 exposure and AOA risk, but not for low-level O 3 exposure. No significant associations between O 3 exposure and accidental injury were observed., Conclusion: Our findings suggest a potential causal relationship between long-term exposure to high-level ambient O 3 and increased risks of AOA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: The impact of asthma on the severity of rhinitis when children with allergic rhinitis (AR) are exposed to air pollutants has not been studied., Methods: Children with AR (65 with asthma, 208 without asthma), aged 6-13 years, were recruited from a hospital in Taichung, Taiwan, between 2007 and 2011. Correlations between Pediatric-Rhinoconjunctivitis-Quality-of-Life score, nasal peak expiratory flow, and air pollutants were compared. With the same age, research time, and form the same city, children with AR (660 with asthma, 3174 without asthma) were selected from a database. Correlations between clinical visit times for AR and air pollutants were compared., Results: In male children with AR and asthma, both clinical and database studies revealed a correlation between higher rhinitis discomfort (quality-of-life score), higher visit times for AR, and higher PM 10 , PM 2.5, NO 2, NMHC concentrations. Correlations between higher nasal inflammation/obstruction (lower expiratory flow) and higher air pollutant concentrations were observed in male children with AR and asthma., Conclusion: In children with AR, comorbid asthma was associated with increased rhinitis severity when they were exposed to air pollutants, and the association was only noted in males. Increased nasal obstruction/inflammation from exposure to air pollutants may be the mechanisms underlying this association., Impact Statement: The influence of asthma on the severity of rhinitis when children with allergic rhinitis (AR) are exposed to air pollutants has not been studied. In children with AR, the correlation between higher rhinitis discomfort, higher number of clinical visits for AR, and higher PM 10 , PM 2.5, NO 2, NMHC concentrations were only noted in those who also had asthma. The correlation was only noted in male. Comorbid asthma was associated with higher rhinitis severity when children with AR are exposed to air pollutants The association was only noted in male., (© 2023. The Author(s), under exclusive licence to the International Pediatric Research Foundation, Inc.)

We aimed to examine the impact of COVID-19 non-pharmaceutical interventions (NPIs) on the relationship between air pollutants and hospital admissions for respiratory and non-respiratory diseases in six metropolitan cities in South Korea. This study compared the associations between particulate matter (PM 10 and PM 2.5 ) and hospital admission for respiratory and non-respiratory diseases before (2016-2019) and during (2020) the implementation of COVID-19 NPIs by using distributed lag non-linear models. In the Pre-COVID-19 period, the association between PM 10 and admission risk for asthma and COPD showed an inverted U-shaped pattern. For PM 2.5 , S-shaped and inverted U-shaped changes were observed in asthma and COPD, respectively. Extremely high and low levels of PM 10 and extremely low levels of PM 2.5 significantly decreased the risk of admission for asthma and COPD. In the Post-COVID-19 outbreak period, the overall cumulative relationship between PM 10 and PM 2.5 and respiratory diseases and the effects of extreme levels of PM 10 and PM 2.5 on respiratory diseases were completely changed. For non-respiratory diseases, PM 10 and PM 2.5 were statistically insignificant for admission risk during both periods. Our study may provide evidence that implementing NPIs and reducing PM 10 and PM 2.5 exposure during the COVID-19 pandemic has contributed to reducing hospital admissions for environment-based respiratory diseases., (© 2024. The Author(s).)

Purpose of Review: In this review, we discuss the current literature examining the impact air pollution and climate change has on asthma onset, control, and exacerbation. This review also addresses the risk of exposure to specific disproportionately affected communities, highlighting health disparities in exposure and asthma outcomes., Recent Findings: Recent studies have shifted from highlighting the associations between asthma exacerbations and indoor and outdoor air pollution. Studies are now focused on confirming the association of asthma incidence from these same exposures. Many studies have linked particulate matter to adverse asthma outcomes, however, the pollutant exposures that pose the greatest risk and the effect of natural disasters fueled by climate change are under current study. Some studies have observed that the true burden that pollutant exposures have on asthma outcomes occurs at the intersection of exposure and vulnerability. Future studies in this area will address social determinants of health, societal factors such as redlining and other systemic racism practices., Summary: Although decades of research support the causal link between gaseous and particulate air pollution and the exacerbation of preexisting asthma, recent studies suggest air pollution can cause incident (new onset) asthma. Studies have started to focus on the underlying drivers of poor outcomes in asthma. Many of the structural impediments to high quality asthma care at the society level (e.g. poverty, redlining, systemic racism) also are risk factors for worsened climate events and air pollution exposure. The individuals in these disproportionately affected groups are doubly affected by worsened exposure and worsened access to care for the resultant asthma exacerbations or incident asthma. More research is needed to understand the specific climate and air pollution mitigation efforts where disproportionately affected communities would derive the most benefit., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

We examined associations between prenatal fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ), and ozone (O 3 ) exposures and child respiratory outcomes through age 8-9 years in 1279 ECHO-PATHWAYS Consortium mother-child dyads. We averaged spatiotemporally modeled air pollutant exposures during four fetal lung development phases: pseudoglandular (5-16 weeks), canalicular (16-24 weeks), saccular (24-36 weeks), and alveolar (36+ weeks). We estimated adjusted relative risks (RR) for current asthma at age 8-9 and asthma with recent exacerbation or atopic disease, and odds ratios (OR) for wheezing trajectories using modified Poisson and multinomial logistic regression, respectively. Effect modification by child sex, maternal asthma, and prenatal environmental tobacco smoke was explored. Across all outcomes, 95% confidence intervals (CI) included the null for all estimates of associations between prenatal air pollution exposures and respiratory outcomes. Pseudoglandular PM 2.5 exposure modestly increased risk of current asthma (RR adj  = 1.15, 95% CI: 0.88-1.51); canalicular PM 2.5 exposure modestly increased risk of asthma with recent exacerbation (RR adj  = 1.26, 95% CI: 0.86-1.86) and persistent wheezing (OR adj  = 1.28, 95% CI: 0.86-1.89). Similar findings were observed for O 3 , but not NO 2 , and associations were strengthened among mothers without asthma. While not statistically distinguishable from the null, trends in effect estimates suggest some adverse associations of early pregnancy air pollution exposures with child respiratory conditions, warranting confirmation in larger samples., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Background: Asthma is a widespread chronic respiratory disease that poses a significant public health challenge. The current study investigated the associations between air pollution and asthma severity among individuals residing near the Sohar industrial port (SIP) in Oman. Despite the presence of multiple major industrial complexes in Oman, limited knowledge regarding their impact on respiratory health is accredited. Hence, the primary objective of this study is to offer valuable insights into the respiratory health consequences of industrial air pollution in Al Batinah North., Methods: The state health clinics' records for patient visits related to asthma were collected for the timeframe spanning 2014 to 2022. Exposure was defined as the distance from the SIP, Majan Industerial Area (MIA), and Sohar Industerial Zone (SIZ) to determine high-, intermediate-, and low-exposure zones (<6 km, 6-12 km and >12 km, respectively). Exposure effect modifications by age, gender, and smoking status were also examined., Results: The conducted cross-sectional study of 410 patients (46.1% males and 53.9% females) living in over 17 areas around SIP revealed that 73.2% of asthmatics were under 50 years old, with severity significantly associated with closeness to the port. Risk ratios were estimated to be (RR:2.42; CI95%: 1.01-5.78), (RR:1.91; CI95%: 1.01-3.6), and (RR:1.68; CI95%: 0.92-3.09) for SIP, MIP, and SIZ areas, respectively, compared to the control area. Falaj Al Qabail (6.4 km) and Majees (6 km) had the highest number of asthma patients ( N 69 and N 72) and highest percentages of severe asthma cases among these patients (28% and 24%) with significant risk ratios (RR:2.97; CI95%: 1.19-7.45 and RR:2.55; CI95%: 1.00-6.48), correspondingly. Moreover, severe asthma prevalence peaked in the 25-50 age group (RR:2.05; CI95%: 1.26-3.33), and this linkage between asthma and age was much more pronounced in males than females. Smoking and exposure to certain contaminants (dust and smoke) also increased the risk of severe asthma symptoms, but their effects were less important in the high-risk zone, suggesting much more important risk factors. A neural network model accurately predicted asthma risk (94.8% accuracy), with proximity to SIP as the most influential predictor., Conclusions: This study highlights the high asthma burden near SIP, linked to port proximity, smoking, and wind direction as major risk factors. These findings inform vital public health policies to reduce air pollution and improve respiratory health in the region, prompting national policy review.

Background: The first 1000 days of life, encompassing pregnancy and the first 2 years after birth, represent a critical period for human health development. Despite this significance, there has been limited research into the associations between mixed exposure to air pollutants during this period and the development of asthma/wheezing in children. Furthermore, the finer sensitivity window of exposure during this crucial developmental phase remains unclear., Objective: This study aims to assess the relationships between prenatal and postnatal exposures to various ambient air pollutants (particulate matter 2.5 [PM 2.5 ], carbon monoxide [CO], sulfur dioxide [SO 2 ], nitrogen dioxide [NO 2 ], and ozone [O 3 ]) and the incidence of childhood asthma/wheezing. In addition, we aimed to pinpoint the potential sensitivity window during which air pollution exerts its effects., Methods: We conducted a prospective birth cohort study wherein pregnant women were recruited during early pregnancy and followed up along with their children. Information regarding maternal and child characteristics was collected through questionnaires during each round of investigation. Diagnosis of asthma/wheezing was obtained from children's medical records. In addition, maternal and child exposures to air pollutants (PM 2.5 CO, SO 2 , NO 2 , and O 3 ) were evaluated using a spatiotemporal land use regression model. To estimate the mutual associations of exposure to mixed air pollutants with the risk of asthma/wheezing in children, we used the quantile g-computation model., Results: In our study cohort of 3725 children, 392 (10.52%) were diagnosed with asthma/wheezing. After the follow-up period, the mean age of the children was 3.2 (SD 0.8) years, and a total of 14,982 person-years were successfully followed up for all study participants. We found that each quartile increase in exposure to mixed air pollutants (PM 2.5 , CO, SO 2 , NO 2 , and O 3 ) during the second trimester of pregnancy was associated with an adjusted hazard ratio (HR) of 1.24 (95% CI 1.04-1.47). Notably, CO made the largest positive contribution (64.28%) to the mutual effect. After categorizing the exposure according to the embryonic respiratory development stages, we observed that each additional quartile of mixed exposure to air pollutants during the pseudoglandular and canalicular stages was associated with HRs of 1.24 (95% CI 1.03-1.51) and 1.23 (95% CI 1.01-1.51), respectively. Moreover, for the first year and first 2 years after birth, each quartile increment of exposure to mixed air pollutants was associated with HRs of 1.65 (95% CI 1.30-2.10) and 2.53 (95% CI 2.16-2.97), respectively. Notably, SO 2 made the largest positive contribution in both phases, accounting for 50.30% and 74.70% of the association, respectively., Conclusions: Exposure to elevated levels of mixed air pollutants during the first 1000 days of life appears to elevate the risk of childhood asthma/wheezing. Specifically, the second trimester, especially during the pseudoglandular and canalicular stages, and the initial 2 years after birth emerge as crucial susceptibility windows., Trial Registration: Chinese Clinical Trial Registry ChiCTR-ROC-17013496; https://tinyurl.com/2ctufw8n., (©Fenglin Tian, Xinqi Zhong, Yufeng Ye, Xiaohan Liu, Guanhao He, Cuiling Wu, Zhiqing Chen, Qijiong Zhu, Siwen Yu, Jingjie Fan, Huan Yao, Wenjun Ma, Xiaomei Dong, Tao Liu. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 17.04.2024.)

Background: Western Montana, USA, experiences complex air pollution patterns with predominant exposure sources from summer wildfire smoke and winter wood smoke. In addition, climate change related temperatures events are becoming more extreme and expected to contribute to increases in hospital admissions for a range of health outcomes. Evaluating while accounting for these exposures (air pollution and temperature) that often occur simultaneously and may act synergistically on health is becoming more important., Methods: We explored short-term exposure to air pollution on children's respiratory health outcomes and how extreme temperature or seasonal period modify the risk of air pollution-associated healthcare events. The main outcome measure included individual-based address located respiratory-related healthcare visits for three categories: asthma, lower respiratory tract infections (LRTI), and upper respiratory tract infections (URTI) across western Montana for ages 0-17 from 2017-2020. We used a time-stratified, case-crossover analysis with distributed lag models to identify sensitive exposure windows of fine particulate matter (PM 2.5 ) lagged from 0 (same-day) to 14 prior-days modified by temperature or season., Results: For asthma, increases of 1 µg/m 3 in PM 2.5 exposure 7-13 days prior a healthcare visit date was associated with increased odds that were magnified during median to colder temperatures and winter periods. For LRTIs, 1 µg/m 3 increases during 12 days of cumulative PM 2.5 with peak exposure periods between 6-12 days before healthcare visit date was associated with elevated LRTI events, also heightened in median to colder temperatures but no seasonal effect was observed. For URTIs, 1 unit increases during 13 days of cumulative PM 2.5 with peak exposure periods between 4-10 days prior event date was associated with greater risk for URTIs visits that were intensified during median to hotter temperatures and spring to summer periods., Conclusions: Delayed, short-term exposure increases of PM 2.5 were associated with elevated odds of all three pediatric respiratory healthcare visit categories in a sparsely population area of the inter-Rocky Mountains, USA. PM 2.5 in colder temperatures tended to increase instances of asthma and LRTIs, while PM 2.5 during hotter periods increased URTIs., (© 2024. The Author(s).)

Air toxics are atmospheric pollutants with hazardous effects on health and the environment. Although methodological constraints have limited the number of air toxics assessed for associations with health and disease, advances in machine learning (ML) enable the assessment of a much larger set of environmental exposures. We used ML methods to conduct a retrospective study to identify combinations of 109 air toxics associated with asthma symptoms among 269 elementary school students in Spokane, Washington. Data on the frequency of asthma symptoms for these children were obtained from Spokane Public Schools. Their exposure to air toxics was estimated by using the Environmental Protection Agency's Air Toxics Screening Assessment and National Air Toxics Assessment. We defined three exposure periods: the most recent year (2019), the last three years (2017-2019), and the last five years (2014-2019). We analyzed the data using the ML-based Data-driven ExposurE Profile (DEEP) extraction method. DEEP identified 25 air toxic combinations associated with asthma symptoms in at least one exposure period. Three combinations (1,1,1-trichloroethane, 2-nitropropane, and 2,4,6-trichlorophenol) were significantly associated with asthma symptoms in all three exposure periods. Four air toxics (1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, BIS (2-ethylhexyl) phthalate (DEHP), and 2,4-dinitrophenol) were associated only in combination with other toxics, and would not have been identified by traditional statistical methods. The application of DEEP also identified a vulnerable subpopulation of children who were exposed to 13 of the 25 significant combinations in at least one exposure period. On average, these children experienced the largest number of asthma symptoms in our sample. By providing evidence on air toxic combinations associated with childhood asthma, our findings may contribute to the regulation of these toxics to improve children's respiratory health., Competing Interests: Declaration of competing interest SA reports grants from National Institutes of Health and Ramboll Foundation. DB and GP report grants from the National Institutes of Health., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: The present study focuses on residential areas of Delhi to identify the elevated levels of ambient PM 10 and PM 2.5 due to biomass burning followed by the coloring activity in the Holi festival celebrated at the end of the winter season. This study also focuses on the health risk assessment and mortality among different age groups due to the change in particulate matter levels during the Holi festival in Delhi, India., Materials and Methods: Secondary data of particulate matters have been procured from the Central Pollution Control Board (CPCB), Delhi Pollution Control Committee (DPCC), and Indian Institute of Tropical Meteorology (IITM), Pune for the period of the pre-, during, and post-Holi period for the year 2018-2020 at four selected residential locations in Delhi, India. The health impacts of particle inhalation were quantified using the AirQ + models., Results: The results indicated the levels of PM 10 and PM 2.5 rise about 3-4 times higher during the Holi festival than on normal days, resulting in health risks and causing an excess number of mortality and Asthma cases in Delhi. Such cases were also found to be higher in 2018, followed by 2019 and 2020 at all the selected locations in Delhi., Conclusions: The study linked the increasing particulate levels in the Holi festival with the increased health risk through short-term exposure of the population. The excess number of cases (ENCs) of mortality, all causes of mortality among adults (age > 30 years) associated with short-term exposure to particulate were also identified.

Air pollution is a global problem associated with various health conditions, causing elevated rates of morbidity and mortality. Major sources of air pollutants include industrial emissions, traffic-related pollutants, and household biomass combustion, in addition to indoor pollutants from chemicals and tobacco. Various types of air pollutants originate from both human activities and natural sources. These include particulate matter, pollen, greenhouse gases, and other harmful gases. Air pollution is linked to allergic diseases, including atopic dermatitis, allergic rhinitis, allergic conjunctivitis, food allergy, and bronchial asthma. These pollutants lead to epithelial barrier dysfunction, dysbiosis, and immune dysregulation. In addition, climate change and global warming may contribute to the exacerbation and the development of allergic diseases related to air pollutants. Epigenetic changes associated with air pollutants have also been connected to the onset of allergic diseases. Furthermore, these changes can be passed down through subsequent generations, causing a higher prevalence of allergic diseases in offspring. Modulation of the aryl hydrocarbon receptor could be a valuable strategy for alleviating air pollutant-induced epidermal barrier dysfunction and atopic dermatitis. A more effective approach to preventing allergic diseases triggered by air pollutants is to reduce exposure to them. Implementing public policies aimed at safeguarding individuals from air pollutant exposure may prove to be the most efficient solution. A pressing need exists for global policy initiatives that prioritize efforts to reduce the production of air pollutants., Competing Interests: Disclosures The authors have no conflicts of interest to report., (Copyright © 2023. Published by Elsevier Inc.)

This review article highlights air pollution as a critical global health concern with emphasis on its effects and role in the development and exacerbation of upper airway and lower airway disease with a focus on allergic rhinitis and asthma. This review underscores the World Health Organization's recognition of air pollution as the biggest environmental threat to human health. It discusses the various components and categories of air pollutants and the evidence-based effects they have on asthma and allergic rhinitis, ranging from pathogenesis to exacerbation of these conditions across various age groups in different geographic locations., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Studies have shown that short- and long-term exposure to particulate matter (PM) can increase the risk of asthma morbidity and mortality. However, the effect of medium-term exposure remains unknown. We aim to examine the effect of medium-term exposure to size-fractioned PM on asthma exacerbations among asthmatics with poor medication adherence., Methods: We conducted a longitudinal study in China based on the National Mobile Asthma Management System Project that specifically and routinely followed asthma exacerbations in asthmatics with poor medication adherence from April 2017 to May 2019. High-resolution satellite remote-sensing data were used to estimate each participant's medium-term exposure (on average 90 days) to size-fractioned PM (PM 1 , PM 2.5 , and PM 10 ) based on the residential address and the date of the follow-up when asthma exacerbations (e.g., hospitalizations and emergency room visits) occurred or the end of the follow-up. The Cox proportional hazards model was employed to examine the hazard ratio of asthma exacerbations associated with each PM after controlling for sex, age, BMI, education level, geographic region, and temperature., Results: Modelling results revealed nonlinear exposure-response associations of asthma exacerbations with medium-term exposure to PM 1 , PM 2.5 , and PM 10 . Specifically, for emergency room visits, we found an increased hazard ratio for PM 1 above 22.8 µg/m 3 (1.060, 95 % CI: 1.025-1.096, per 1 µg/m 3 increase), PM 2.5 above 38.2 µg/m 3 (1.032, 95 % CI: 1.010-1.054), and PM 10 above 78.6 µg/m 3 (1.019, 95 % CI: 1.006-1.032). For hospitalizations, we also found an increased hazard ratio for PM 1 above 20.3 µg/m 3 (1.055, 95 % CI: 1.001-1.111) and PM 2.5 above 39.2 µg/m 3 (1.038, 95 % CI: 1.003-1.074). Furthermore, the effects of PM were greater for a longer exposure window (90-180 days) and among participants with a high BMI., Conclusion: This study suggests that medium-term exposure to PM is associated with an increased risk of asthma exacerbations in asthmatics with poor medication adherence, with a higher risk from smaller PM., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Declaration of competing interest All the authors declared no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction and Objective: Smog, which contains fine dusts, non-metal oxides, metals and organic compounds can have irritating, allergenic and immunomodulatory effects leading to the development of respiratory diseases and their exacerbations. The aim of the study was to search for a relationship between concentrations of air pollutants and the frequency of hospitalizations due to exacerbation of asthma, chronic obstructive pulmonary disease, or abnormalitis in breathing., Material and Methods: Hospital admission data was accessed from the hospital digital in-formation system. From the publicly available database of the Chief Inspectorate for Environmental Protection, data concerning the concentrations of pollutants, such as PM 2.5 and PM 10 , sulphur oxide IV (SO 2 ), nitric oxide IV (NO 2 ), carbon monoxide II (CO), benzene and ozone (O 3 ), measured daily with hourly accuracy was used. The results of the average concentrations of air pollutants were compared with the rates of hospitalization in the corresponding time intervals., Results: A number of statistically significant correlations were shown indicating the role of increased concentrations of each of the tested contaminants in the frequency of hospitalizations. In particular, strongly positive correlations were shown between the frequency of hospitalizations due to COPD and PM 2.5 and PM 10 , asthma with benzene and NO 2 , and for respiratory disorders in general with benzene, CO and SO 2 ., Conclusions: The results indicate that air pollution can be a significant modifiable risk factor for exacerbations of respiratory diseases and therefore its avoidance plays an important role in primary prevention.

Background: Constrained by no proper way to assess cumulative exposure, the joint effect of air pollution cumulative exposure doses on childhood asthma and wheezing (AW) was not understood., Objective: To assess the association between cumulative exposure to multiple air pollutants in early life and childhood AW., Methods: We designed a nested case-control study based on the birth cohort in Jinan City. Children with AW followed up within 2 years after birth were treated as cases, and non-cases in this cohort were treated as the control source population, and the propensity score matching method was used to match each case to 5 controls. We calculated the individual cumulative outdoor exposure doses for each period using an inverse distance weighted model, alongside the complex Simpson's formula, accounting for outdoor time and respiratory volume. The Least absolute shrinkage and selection operator (Lasso) regression was performed to screen for covariates. To analyze the joint effects of pollutants, we employed the weighted quantile sum (WQS) regression model in conjunction with conditional logistic regression., Results: 84 cases and 420 controls were included in this study. The odds ratio (OR) with 95% confidence interval (CI) of the impact of cumulative exposure (mg/m 3 ) after birth on childhood AW was 1.78 (1.15-2.74) for SO 2 , 1.69 (1.11-2.57) for NO 2 , and 1.65 (1.09-2.52) for PM 2.5 , respectively. Furthermore, with each 25th percentile increase in the WQS index, the overall risk of cumulative doses for six pollutants exposure after birth on AW increased by an adjusted OR of 1.10 (1.03, 1.18), and SO 2 , PM 2.5 , and NO 2 contributed the most to the WQS index. However, no statistically significant association was found between cumulative exposure to all pollutants before birth and childhood AW., Conclusions: There was a joint effect of the cumulative exposure dose of outdoor air pollutants after birth on AW in children aged 0-2 years. And traffic-related pollutants (SO 2 , PM 2.5 , and NO 2 ) make a greater contribution to the joint effect., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: In recent years numerous initiatives aimed at reducing air pollution have been undertaken in Poland. The general objective was to examine the correlation between air pollution measured by the level of particulate matter ≤10 μm in diameter (PM 10 ) and emergency hospitalizations due to chronic obstructive pulmonary disease (COPD) and asthma in 16 Polish cities (capitals of the regions)., Material and Methods: The authors aimed to diagnose the situation across 16 cities over a 5‑year period (2014-2019). Data on the number of hospitalizations was retrieved from the national public insurance system, the National Health Fund. A total number of 22 600 emergency hospitalizations was analyzed (12 000 and 10 600 in 2014 and 2019, respectively). The data on air pollution was accessed via the public register of the Chief Inspectorate for Environmental Protection air quality database. The authors of this article have used the data on PM 10 daily exposure in each of the 16 cities in 2014 and 2019. Statistical methods included: non-parametric tests, a 2-stage modelling approach for time-series data, and multivariate meta-analysis of the results., Results: The results indicated that there was a statistically significant decrease in PM 10 concentration in 2019 in comparison to 2014 in all cities, mainly in the autumn and winter season. However, the correlation between the improvement in the air quality and a decrease in emergency hospitalizations due to asthma and COPD turned out to not be as strong as expected. The authors observed a strong correlation between PM 10 concentrations and hospitalizations due to asthma and COPD, but only when air quality norms were significantly above acceptable levels., Conclusions: Air pollution measured by PM 10 concentration might be used as one of the predictors of the asthma and COPD emergency hospitalization risk, yet other factors like respiratory tract infection, health care organizational aspect, patient self-control, compliance and comorbidities should also be taken into consideration. Int J Occup Med Environ Health. 2024;37(1):110-27., (This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.)

Asthma is a common chronic heterogeneous disease. Outdoor air pollutants are an important cause of acute asthma. Until now, the association between the risk of acute asthma and outdoor air pollutants is unclear. And the relationship between the different phenotypes of asthma and outdoor air pollutants has not been reported. Thus, an analysis of the association between outdoor air pollutants and daily acute asthma inpatient and outpatient visits in Xi'an, China, from January 1 to December 31, 2018, was conducted. A total of 3395 people were included in the study. The statistical analysis and relational analysis based on the logistic regression were used for illustrating the relatedness of the acute asthma risk factor and phenotype with outdoor air pollutants, while the age, gender, pollen peak and non-pollen peak periods, high type 2 (T2) asthma and non-high T2 asthma were also stratified. Results showed that particulate matter with particle size below 10 μm and 2.5 μm (PM 10 and PM 2.5 ), sulfur dioxide(SO 2 ), nitrogen dioxide(NO 2 ), and carbon monoxide(CO) increase the risk of acute asthma and that air pollutants have a lagged effect on asthma patients. PM 10 , NO 2 , CO, and Ozone (O 3 ) are associated with an increased risk of acute attacks of high T2 asthma. PM 10 , PM 2.5 , SO 2 , NO 2 and CO are associated with an increased risk of acute asthma in males of 0-16 years old. PM 10 and PM 2.5 are more harmful to asthma patients with abnormal lung function., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Ambient air pollution has been associated with asthma onset and exacerbation in children. Whether improvement in air quality due to reduced industrial emissions has resulted in improved health outcomes such as asthma in some localities has usually been assessed indirectly with studies on between-subject comparisons of air pollution from all sources and health outcomes. In this study we directly assessed, within small areas in the province of Quebec (Canada), the influence of changes in local industrial fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ), and sulfur dioxide (SO 2 ) concentrations, on changes in annual asthma onset rates in children (≤12 years old) with a longitudinal ecological design. We identified the yearly number of new cases of childhood asthma in 1282 small areas (census tracts or local community service centers) for the years 2002, 2004, 2005, 2006, and 2015. Annual average concentrations of industrial air pollutants for each of the geographic areas, and three sectors (i.e., pulp and paper mills, petroleum refineries, and metal smelters) were estimated by the Polair3D chemical transport model. Fixed-effects negative binomial models adjusted for household income were used to assess associations; additional adjustments for environmental tobacco smoke, background pollutant concentrations, vegetation coverage, and sociodemographic characteristics were conducted in sensitivity analyses. The incidence rate ratios (IRR) for childhood asthma onset for the interquartile increase in total industrial PM 2.5 , NO 2 , and SO 2 were 1.016 (95% confidence interval, CI: 1.006-1.026), 1.063 (1.045-1.090), and 1.048 (1.031-1.080), respectively. Positive associations were also found with pollutant concentrations from most individual sectors. Results suggest that changes in industrial pollutant concentrations influence childhood asthma onset rates in small localities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Air pollution is a risk factor for asthma and respiratory infection. Avoidance of air pollution is the best approach to mitigating the impacts of pollution. Personal preventive strategies are possible, but policy interventions are the most effective ways to prevent pollution and its effect on asthma and respiratory infection., (Copyright © 2023 Elsevier Inc. All rights reserved.)

While the number and types of indoor air pollutants is rising, much is suspected but little is known about the impact of their potentially synergistic interactions, upon human health. Gases, particulate matter, organic compounds but also allergens and viruses, fall within the 'pollutant' definition. Distinct populations, such as children and allergy and asthma sufferers are highly susceptible, while a low socioeconomic background is a further susceptibility factor; however, no specific guidance is available. We spend most of our time indoors; for children, the school environment is of paramount importance and potentially amenable to intervention. The interactions between some pollutant classes have been studied. However, a lot is missing with respect to understanding interactions between specific pollutants of different classes in terms of concentrations, timing and sequence, to improve targeting and upgrade standards. SynAir-G is a European Commission-funded project aiming to reveal and quantify synergistic interactions between different pollutants affecting health, from mechanisms to real life, focusing on the school setting. It will develop a comprehensive and responsive multipollutant monitoring system, advance environmentally friendly interventions, and disseminate the generated knowledge to relevant stakeholders in accessible and actionable formats. The aim of this article it to put forward the SynAir-G hypothesis, and describe its background and objectives., (© 2023 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: This study aimed to explore the relationship between air pollution and hospital admissions for asthma in older adults, and to further assess the health and economic burden of asthma admissions attributable to air pollution., Methods: We collected information on asthma cases in people over 65 years of age from nine cities in Sichuan province, as well as air pollution and meteorological data. The relationship between short-term air pollutant exposure and daily asthma hospitalizations was analyzed using the generalized additive model (GAM), and stratified by gender, age, and season. In addition, we assessed the economic burden of hospitalization for air pollution-related asthma in older adults using the cost of disease approach., Results: The single pollutant model showed that every 1 mg/m 3 increase in CO was linked with an increase in daily hospitalizations for older adults with asthma, with relative risk values of 1.327 (95% CI: 1.116-1.577) at lag7. Each 10 μg/m 3 increase in NO 2 , O 3 , PM 10 , PM 2.5 and SO 2 , on asthma hospitalization, with relative risk values of 1.044 (95% CI: 1.011-1.078), 1.018 (95% CI: 1.002-1.034), 1.013 (95% CI: 1.004-1.022), 1.015 (95% CI: 1.003-1.028) and 1.13 (95% CI: 1.041-1.227), respectively. Stratified analysis shows that stronger associations between air pollution and asthma HAs among older adult in females, those aged 65-69 years, and in the warm season, although all of the differences between subgroups did not reach statistical significance. During the study period, the number of asthma hospitalizations attributable to PM 2.5 , PM 10 , and NO 2 pollution was 764, 581 and 95, respectively, which resulted in a total economic cost of 6.222 million CNY, 4.73 million CNY and 0.776 million CNY, respectively., Conclusion: This study suggests that short-term exposure to air pollutants is positively associated with an increase in numbers of asthma of people over 65 years of age in Sichuan province, and short-term exposure to excessive PM and NO 2 brings health and economic burden to individuals and society., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhang, Yang, Jiang, Gao, Yang, Feng and Yang.)

Background: Non-optimum temperatures are associated with increased risk of respiratory diseases, but the effects of apparent temperature (AT) on respiratory diseases remain to be investigated., Methods: Using daily data from 2016 to 2020 in Ganzhou, a large city in southern China, we analyzed the impact of AT on outpatient and inpatient visits for respiratory diseases. We considered total respiratory diseases and five subtypes (influenza and pneumonia, upper respiratory tract infection (URTI), lower respiratory tract infection (LRTI), asthma and chronic obstructive pulmonary disease [COPD]). Our analysis employed a distributed lag nonlinear model (DLNM) combined with a generalized additive model (GAM)., Results: We recorded 94,952 outpatients and 72,410 inpatients for respiratory diseases. We found AT significantly non-linearly associated with daily outpatient and inpatient visits for total respiratory diseases, influenza and pneumonia, and URTI, primarily during comfortable AT levels, while it was exclusively related with daily inpatient visits for LRTI and COPD. Moderate heat (32.1 °C, the 75.0th centile) was observed with a significant effect on both daily outpatient and inpatient visits for total respiratory diseases at a relative risk of 1.561 (1.161, 2.098) and 1.276 (1.027, 1.585), respectively (both P < 0.05), while the results of inpatients became insignificant with the adjustment for CO and O 3 . The attributable fractions in outpatients and inpatients were as follows: total respiratory diseases (24.43% and 18.69%), influenza and pneumonia (31.54% and 17.33%), URTI (23.03% and 32.91%), LRTI (37.49% and 30.00%), asthma (9.83% and 3.39%), and COPD (30.67% and 10.65%). Stratified analyses showed that children ≤5 years old were more susceptible to moderate heat than older participants., Conclusions: In conclusion, our results indicated moderate heat increase the risk of daily outpatient and inpatient visits for respiratory diseases, especially among children under the age of 5.

Background: Exposure to fine particulate matter (PM 2.5 ) has been associated with allergic diseases, including asthma. However, information about the effects of specific PM 2.5 components is limited. This study aimed to investigate the relationship of exposure to chemical components of PM 2.5 during pregnancy and early childhood with the development of asthma, allergies, and sensitization in school-age children., Methods: This study included 2,408 children in the second grade of elementary school. Questionnaire surveys of respiratory/allergic symptoms and measurements of serum total IgE and specific IgE levels to house dust mite (HDM) and animal proteins were conducted. Exposures to ambient PM 2.5 mass, sulfate (SO 4 2- ), nitrate (NO 3 - ), ammonium (NH 4 + ), elemental carbon (EC), and organic carbon (OC) of PM 2.5 in participants' residences from conception to age six were estimated using predictive models. Multiple logistic regression analysis was used to analyze the association of respiratory/allergic symptoms and allergen sensitization with estimated exposure concentrations, after adjustment for survey year, sex, season of birth, feeding method during infancy, presence of siblings, history of lower respiratory tract infection, use of childcare facilities, passive smoking, presence of pets, mother's age, history of allergic diseases, smoking during pregnancy, and annual household income., Results: No significant association was found between PM 2.5 and its component concentrations and asthma. However, wheezing significantly increased with mean NO 3 - concentrations during pregnancy (odds ratio of 1.64 [95% confidence interval: 1.10, 2.47] for an interquartile range increase). Significant associations were also found between EC in the second trimester of pregnancy and PM 2.5 , NO 3 - , EC, and OC concentrations in early childhood. Higher PM 2.5 , SO 4 - , and NH 4 + concentrations during the second trimester increased the risk of rhinitis. Sensitizations to HDM and animal proteins were significantly associated with exposure to components such as SO 4 2- and NH 4 + during pregnancy but not with postnatal exposure., Conclusions: Exposures to NO 3 - , EC, and OC during pregnancy and early childhood were associated with wheezing. SO 4 2- and NH 4 + exposures during pregnancy were associated with sensitization to HDM and animal proteins. Asthma was not associated with exposure to PM 2.5 and its main components at any period.

A case-control study was conducted to examine the association of particulate matter exposure during the pre-natal (the first, second, and third trimesters. and the whole pregnancy) and post-natal periods (the first year after birth) with childhood asthma in Beijing, China. Multivariable logistic regressions showed that childhood asthma was significantly associated with exposures to PM 2.5 and PM 10 during the entire pregnancy, with ORs of 1.28(95%CI:1.06-1.56) and 1.21(95%CI:1.02-1.42), respectively. The highest association with a 10 μg/m 3 increase in PM 2.5 and PM 10 were both seen for the second trimester, with ORs of 1.17(95% CI: 1.05-1.30) and 1.14(95% CI: 1.04-1.24). Subgroup analyses suggested that significant and positive effects were subject to be observed in children with a family history of atopy. This study added evidence that exposures to PM 2.5 and PM 10 during pregnancy might increase the risk of childhood asthma in seriously polluted area, highlighting stronger associations in the second trimester.

Although numerous studies have linked asthma to air temperature and pollution, few studies have examined their interactive effects on asthma outpatient visits. This study investigated how air pollutants and their interactions with temperature affect asthma outpatient visits in a city in northern Chinaduring the time period 2018 - 2020 . . As the results, 24,163 asthma outpatients were recorded, a 10-μg/m 3 increase in PM 10 , PM 2.5 , SO 2 , and NO 2 concentrations was associated with significant increases in visits of 3.47% (95% CI: 2.35%-4.60%), 0.83% (95% CI: 0.36%-1.30%), 3.17% (95% CI: 1.47%-4.90%), and 8.90% (95% CI: 6.09%-11.79%), respectively. The effect was stronger in females than males, and stronger in the elderly (≥65 years) than among the young. The interaction between low temperatures and high air pollution levels significantly increased the number of asthma outpatient visits. This study emphasizesthe importance of reducing air pollution in order to lessen the effects of cold.

Rapidly changing wildfire regimes across the Western United States have driven more frequent and severe wildfires, resulting in wide-ranging societal threats from wildfires and wildfire-generated smoke. However, common measures of fire severity focus on what is burned, disregarding the societal impacts of smoke generated from each fire. We combine satellite-derived fire scars, air parcel trajectories from individual fires, and predicted smoke PM 2 . 5 to link source fires to resulting smoke PM 2 . 5 and health impacts experienced by populations in the contiguous United States from April 2006 to 2020. We quantify fire-specific accumulated smoke exposure based on the cumulative population exposed to smoke PM 2 . 5 over the duration of a fire and estimate excess asthma-related emergency department (ED) visits as a result of this exposure. We find that excess asthma visits attributable to each fire are only moderately correlated with common measures of wildfire severity, including burned area, structures destroyed, and suppression cost. Additionally, while recent California fires contributed nearly half of the country's smoke-related excess asthma ED visits during our study period, the most severe individual fire was the 2007 Bugaboo fire in the Southeast. We estimate that a majority of smoke PM 2 . 5 comes from sources outside the local jurisdictions where the smoke is experienced, with 87% coming from fires in other counties and 60% from fires in other states. Our approach could enable broad-scale assessment of whether specific fire characteristics affect smoke toxicity or impact, inform cost-effectiveness assessments for allocation of suppression resources, and help clarify the growing transboundary nature of local air quality., Competing Interests: Competing interests statement:The authors declare no competing interest.

Background: Previous studies found exposure to air pollution leads to exacerbations of asthma in paediatric and adult patients and increases asthma-related emergency hospital admissions (AREHA)., Methods: AREHAs and levels of air pollutants (PM 10 , PM 2.5 and NO 2 ) were obtained from Mexico City for the period 2017-2019. A time-series approach was used to explore the relationship between air pollutants and AREHA. Relative risks of AREHA were estimated using a negative binomial regression in young children (less than 5 years) and adults (greater than 18 years)., Results: There was a positive association between AREHA and PM 10 , PM 2.5 and NO 2 in adults, which remained after mutual adjustment for these pollutants. The relative risk (RR) of admission in adults increased by 3% (95% CI 1% to 4%) for a 10 µg/m 3 increase in PM 10 , 1% (0.03% to 3%) for a 5 µg/m 3 increase in PM 2.5 and by 1% (0.06% to 2%) for a 5 µg/m 3 increase in NO 2 . In contrast, in young children, AREHAs were negatively associated with PM 10 after adjustment for NO 2 (RR 0.97 (0.95 to 0.99) for a 10 µg/m 3 and with NO 2 after adjustment for PM 10 and PM 2.5 (RR 0.98 (0.96 to 0.99) and 0.97 (0.96 to 0.99), respectively, for a 5 µg/m 3 increase in NO 2 ). AREHAs in children were not associated with PM 2.5 after adjustment for NO 2 ., Conclusions: Ambient air pollution, within the previous week, was associated with emergency hospital admissions for asthma to public hospitals in adults in Mexico City. The relationship in children was less consistent. Further work is needed to explore why differences between adults and children exist to inform appropriate interventions to benefit public health., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Exposure to air pollutants may cause immune responses and further allergic diseases, but existing studies have mostly, if not all, focused on effects of short-term exposure to PM 2.5 on allergic diseases., Objectives: We estimated associations of long-term exposure to PM 2.5 chemical constituents with allergic disease risks and effect modification., Methods: We used the baseline of a newly established, provincially representative cohort of 51,480 participants in southwest China. The presence of allergic rhinitis, allergic asthma, urticaria, and allergic conjunctivitis was self-reported by following a formed questionnaire in face-to-face interviews. The average concentrations of PM 2.5 chemical constituents (NO 3 - , SO 4 2- , NH 4 + , organic matter [OM], and black carbon [BC]) over participants' residence were estimated using machine learning models. Logistic regression with double robust estimator and weighted quantile sum regression were used to estimate the effects of PM 2.5 chemical constituents on allergic disease risks, as well as relative importance of each PM 2.5 chemical constituent., Results: Per interquartile range increase in the concentration of all PM 2.5 chemical constituents was associated with the elevated risks for allergic asthma (OR = 1.79 [1.41-2.26]), allergic conjunctivitis (1.54 [1.19-2.00]), urticaria (1.36 [1.25-1.48]), and allergic rhinitis (1.18 [1.11-1.26]). NO 3 - contributed more to risks for allergic asthma (weight = 46.05 %), urticaria (72.29 %), and allergic conjunctivitis (47.65 %), while NH 4 + contributed more to allergic rhinitis (78.07 %). OM contributed most to the risks for allergic asthma (30.81 %) and allergic conjunctivitis (31.40 %). BC was also associated with allergic rhinitis, urticaria, and allergic conjunctivitis, only with a considerable weight for urticaria (24.59 %). Joint effects of PM 2.5 chemical constituents on risks for allergic rhinitis and urticaria were stronger in minorities and farmers than their counterparts., Conclusion: Long-term exposure to PM 2.5 chemical constituents was associated with the increased allergic disease risks, with NO 3 - and NH 4 + accounting for the largest variance of the associations. Our findings would serve as scientific evidence for developing more explicit strategies of air pollution control., Competing Interests: Declaration of competing interest The authors declare they have nothing to disclose., (Copyright © 2023 Elsevier B.V. All rights reserved.)

A cornerstone of asthma management is maintaining physical activity (PA), but this may lead to increased exposure to, and deeper inhalation of, pollutants. Furthermore, children and adolescents may be more susceptible to the deleterious impacts of such exposures. Despite the recent air quality campaigns and media coverage surrounding the dangers of air pollution to respiratory health, few target children and their understanding of such issues.Using semi structured interviews, understanding of PA, air pollution and their interaction was explored with 25 youth aged 7-17 years. Utilising NVIVO 12 software, an atheoretical, inductive thematic analysis was conducted to identify key themes which were subsequently presented as pen profiles with the number of common responses within a theme indicative of its strength.The majority (88%) of youth's indicated traffic-related air pollution and global manufacturing as key sources of air pollution. Whilst all youths were aware of outdoor pollution, only 52% were aware of indoor air pollutants, of which 62% had asthma. Despite some uncertainty, all youths described pollution in a negative fashion, with 52% linking air pollution to undesirable effects on health, specifically respiratory health. PA in a polluted area was thought to be more dangerous than beneficial by 44%, although 24% suggested the benefits of PA would outweigh any detriment from pollution.Youth are aware of, and potentially compensate for, the interaction between air pollution and PA. Strategies are needed to allow youth to make more informed decisions regarding how to promote PA whilst minimising exposure to air pollution., (© 2023. The Author(s).)

Background: Acute bronchiolitis and air pollution are both risk factor of pediatric asthma. This study aimed to assess subsequent exposure to air pollutants related to the inception of preschool asthma in infants with acute bronchiolitis. This study aimed to assess subsequent exposure to air pollutants related to the inception of preschool asthma in infants with acute bronchiolitis., Methods: A nested case-control retrospective study was performed at the Kaohsiung Medical University Hospital systems between 2009 and 2019. The average concentration of PM 10 , PM 2.5 , SO 2 , NO, NO 2, and NO X was collected for three, six, and twelve months after the first infected episode. Adjusted regression models were employed to evaluate the association between asthma and air pollution exposure after bronchiolitis., Results: Two thousand six hundred thirty-seven children with acute bronchiolitis were included. Exposure to PM 10 , PM 2.5 , SO 2 , NO, NO 2, and NO X in the three, six, and twelve months following an episode of bronchiolitis was found to significantly increase the risk of preschool asthma in infants with a history of bronchiolitis.(OR, 95%CI: PM 10 = 1.517-1.559, 1.354-1.744; PM 2.5 = 2.510-2.603, 2.148-3.061; SO 2 = 1.970-2.040, 1.724-2.342; ; NO = 1.915-1.950, 1.647-2.272; NO 2 = 1.915-1.950, 1.647-2.272; NO X = 1.752-1.970, 1.508-2.252) In a sensitive analysis of hospitalized infants, only PM 10 , PM 2.5 , SO 2, and NO were found to have significant effects during all time periods. (OR, 95%CI: PM 10 = 1.613-1.650, 1.240-2.140; PM 2.5 = 2.208-2.286, 1.568-3.061; SO 2 = 1.679-1.622, 1.197-2.292; NO = 1.525-1.557, 1.094-2.181) CONCLUSION: The presence of ambient PM 10 , PM 2.5 , SO 2 and NO in the three, six, and twelve months following an episode of acute bronchiolitis has been linked to the development of preschool asthma in infants with a history of acute bronchiolitis., (© 2023. The Author(s).)

Objective: The length of hospital stay (LOS) is a proxy of asthma exacerbation severity and healthcare cost. The study aims to estimate the effect of ambient air pollution on pediatric asthma LOS in the Bronx, NY., Methods: A total of 1,920 children admitted to the hospital in Bronx, NY due to asthma during 2017-2019 period were included in the study. Demographic and clinical parameters were obtained from medical records. Daily ozone (O 3 ) and fine particulate matter (PM 2.5 ) measurements were obtained from local air quality networks. Poisson regression adjusting for gender, age, weight status, respiratory infections including influenza, and ambient temperature was applied to determine whether there was an association of air pollution with length of hospital stay., Results: The mean LOS varied by age, sex, weight status, influenza vaccination status, respiratory viral panel (RVP) results, asthma controller use, and asthma classification. After controlling for these factors in Poisson regression, the mean LOS increased up to 10.62% (95%CI: 0.78-21.41; p  = 0.03) for an increase of 10 μg/m 3 of PM 2.5 exposure on admission day, and 3.90% (95%CI = 0.06-7.88; p  = 0.05) for an increase of 10 ppbv of O 3 concentration during the previous day., Conclusion: Ambient particulate and ozone pollution is associated with lengthier hospital stays for pediatric asthma, potentially indicating more severe asthma exacerbations.

Introduction: Air pollution has been shown to have a significant impact on morbidity and mortality of respiratory illnesses including asthma., Areas Covered: Outdoor air pollution consists of a mixture of individual pollutants including vehicle traffic and industrial pollution. Studies have implicated an array of individual components of air pollution, with PM 2.5 , NO 2 , SO 2 , and ozone being the most classically described, and newer literature implicating other pollutants such as black carbon and volatile organic compounds. Epidemiological and cohort studies have described incidence and prevalence of pollution-related asthma and investigated both acute and chronic air pollution exposure as they relate to asthma outcomes. There is an increasing body of literature tying disparities in pollution exposure to clinical outcomes. In this narrative review, we assessed the published research investigating the association of pollution with asthma outcomes, focusing on the adult population and health care disparities., Expert Opinion: Pollution has multiple deleterious effects on respiratory health but there is a lack of data on individualized pollution monitoring, making it difficult to establish a temporal relationship between exposure and symptoms, thereby limiting our understanding of safe exposure levels. Future research should focus on more personalized monitoring and treatment plans for mitigating exposure.

At present, evidence of the associations between carbon monoxide (CO) and respiratory diseases (RD) in Northwest China is limited and controversial. The aim of this study is to evaluate the impact of ambient CO on outpatient visits for RD in Lanzhou, China. The daily amount of outpatient visits for total and cause-specific RD, air pollutant, and weather variables were collected in Lanzhou, China from 1st January 2013 to 31st December 2019. A generalized additive model and distributed lag nonlinear model were used to assess associations between CO and outpatient visits for RD. During the study period, a total of 1,623,361 RD outpatient visits were recorded. For each interquartile range (IQR) (0.77 mg/m 3 ) increase in CO, the relative risk (RR) was 1.163 (95% CI: 1.138, 1.188) for total RD at lag07, 1.153 (95% CI: 1.128,1.179) for upper respiratory tract infection (URTI) at lag07, 1.379 (95% CI: 1.338,1.422) for pneumonia at lag07, 1.029 (95% CI: 0.997,1.062) for chronic obstructive pulmonary disease (COPD) lag04, 1.068 (95% CI: 1.028,1.110) for asthma lag03, and 1.212 (95% CI: 1.178,1.247) for bronchitis lag07, respectively. In the subgroup analyses, the impacts of CO were more pronounced on total RD, pneumonia, COPD, and bronchitis in males than females, while the opposite was true in URTI and asthma. The impact of CO on RD was the strongest for children under 15 years-of-age. We also found significantly stronger effects during cold seasons compared to warm seasons. In addition, we observed a roughly linear exposure-response curve between CO and RD with no threshold effect. This study in Lanzhou revealed a remarkable association between CO level and an elevated risk of total and cause-specific RD outpatient visits, especially for pneumonia., (© 2023. The Author(s) under exclusive licence to International Society of Biometeorology.)

Background: Air pollution, weather, pollen, and influenza are typical aggravating factors for asthma. Previous studies have identified risk factors using regression-based and ensemble models. However, studies that consider complex relationships and interactions among these factors have yet to be conducted. Although deep learning algorithms can address this problem, further research on modeling and interpreting the results is warranted., Methods: In this study, from 2015 to 2019, information about air pollutants, weather conditions, pollen, and influenza were utilized to predict the number of emergency room patients and outpatients with asthma using recurrent neural network, long short-term memory (LSTM), and gated recurrent unit models. The relative importance of the environmental factors in asthma exacerbation was quantified through a feature importance analysis., Results: We found that LSTM was the best algorithm for modeling patients with asthma. Our results demonstrated that influenza, temperature, PM 10 , NO 2, CO, and pollen had a significant impact on asthma exacerbation. In addition, the week of the year and the number of holidays per week were an important factor to model the seasonality of the number of asthma patients and the effect of holiday clinic closures, respectively., Conclusion: LSTM is an excellent algorithm for modeling complex epidemiological relationships, encompassing nonlinearity, lagged responses, and interactions. Our study findings can guide policymakers in their efforts to understand the environmental factors of asthma exacerbation., (© 2023. The Author(s).)

PM 2.5 (fine particulate matter ≤2.5 μm in diameter) is a key pollutant that can produce acute asthma exacerbations and longer-term deterioration of respiratory health. Individual exposure to PM 2.5 is unique and varies across microenvironments. Low-cost sensors (LCS) can collect data at a spatiotemporal resolution previously unattainable, allowing the study of exposures across microenvironments. The aim of this study is to investigate the acute effects of personal exposure to PM 2.5 on self-reported asthma-related health. Twenty-eight non-smoking adults with asthma living in Scotland collected PM 2.5 personal exposure data using LCS. Measurements were made at a 2-min time resolution for a period of 7 days as participants conducted their typical daily routines. Concurrently, participants were asked to keep a detailed time-activity diary, logging their activities and microenvironments, along with hourly information on their respiratory health and medication use. Health outcomes were modelled as a function of hourly PM 2.5 concentration (plus 1- and 2-h lag) using generalized mixed-effects models adjusted for temperature and relative humidity. Personal exposures to PM 2.5 varied across microenvironments, with the largest average microenvironmental exposure observed in private residences (11.5 ± 48.6 μg/m 3 ) and lowest in the work microenvironment (2.9 ± 11.3 μg/m 3 ). The most frequently reported asthma symptoms, wheezing, chest tightness and cough, were reported on 3.4%, 1.6% and 1.6% of participant-hours, respectively. The odds of reporting asthma symptoms increased per interquartile range (IQR) in PM 2.5 exposure (odds ratio (OR) 1.29, 95% CI 1.07-1.54) for same-hour exposure. Despite this, no association was observed between reliever inhaler use (non-routine, non-exercise related) and PM 2.5 exposure (OR 1.02, 95% CI 0.71-1.48). Current air quality monitoring practices are inadequate to detect acute asthma symptom prevalence resulting from PM 2.5 exposure; to detect these requires high-resolution air quality data and health information collected in situ. Personal exposure monitoring could have significant implications for asthma self-management and clinical practice., Competing Interests: Declaration of competing interest None., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Although 1 billion people live in informal (slum) settlements, the consequences for respiratory health of living in these settlements remain largely unknown. This study investigated whether children living in an informal settlement in Nairobi, Kenya are at increased risk of asthma symptoms., Methods: Children attending schools in Mukuru (an informal settlement in Nairobi) and a more affluent area (Buruburu) were compared. Questionnaires quantified respiratory symptoms and environmental exposures; spirometry was performed; personal exposure to particulate matter (PM 2.5 ) was estimated., Results: 2373 children participated, 1277 in Mukuru (median age, IQR 11, 9-13 years, 53% girls), and 1096 in Buruburu (10, 8-12 years, 52% girls). Mukuru schoolchildren were from less affluent homes, had greater exposure to pollution sources and PM 2.5 . When compared with Buruburu schoolchildren, Mukuru schoolchildren had a greater prevalence of symptoms, 'current wheeze' (9.5% vs 6.4%, p=0.007) and 'trouble breathing' (16.3% vs 12.6%, p=0.01), and these symptoms were more severe and problematic. Diagnosed asthma was more common in Buruburu (2.8% vs 1.2%, p=0.004). Spirometry did not differ between Mukuru and Buruburu. Regardless of community, significant adverse associations were observed with self-reported exposure to 'vapours, dusts, gases, fumes', mosquito coil burning, adult smoker(s) in the home, refuse burning near homes and residential proximity to roads., Conclusion: Children living in informal settlements are more likely to develop wheezing symptoms consistent with asthma that are more severe but less likely to be diagnosed as asthma. Self-reported but not objectively measured air pollution exposure was associated with increased risk of asthma symptoms., Competing Interests: Competing interests: RD has declared employment by the University of Stirling for the duration of the study. ML has declared employment by the Institute of Occupational Medicine and funding for the study from UKRI MRC/Kenya National Research Fund. JKQ has declared personal funding from GlaxoSmithKline, Boehringer Ingelheim, AstraZeneca, Chiesi, Teva, Insmed, Bayer and institutional funding from UKRI MRC, Health Data Research UK, GlaxoSmithKline, Bayer, Boehringer Ingelheim, Chiesi, AstraZeneca and Asthma and Lung UK. All other authors have declared they have nothing to disclose., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

Ultrafine particles (UFP; particulate matter <0.1 μm in diameter) may be more harmful to human health than larger particles, but epidemiological evidence on their health effects is still limited. In this study, we examined the association between short-term exposure to UFP and mortality and hospital admissions in Copenhagen, Denmark. Daily concentrations of UFP (measured as particle number concentration in a size range 11-700 nm) and meteorological variables were monitored at an urban background station in central Copenhagen during 2002-2018. Daily counts of deaths from all non-accidental causes, as well as deaths and hospital admissions from cardiovascular and respiratory diseases were obtained from Danish registers. Mortality and hospital admissions associated with an interquartile range (IQR) increase in UFP exposure on a concurrent day and up to six preceding days prior to the death or admission were examined in a case-crossover study design. Odds ratios (OR) with 95% confidence intervals (CI) per one IQR increase in UFP were estimated after adjusting for temperature and relative humidity. We observed 140,079 deaths in total, 236,003 respiratory and 342,074 cardiovascular hospital admissions between 2002 and 2018. Hospital admissions due to respiratory and cardiovascular diseases were significantly positively associated with one IQR increase in UFP (OR: 1.04 [95% CI: 1.01, 1.07], lag 0-4, and 1.02 [1.00, 1.04], lag 0-1, respectively). Among the specific causes, the strongest associations were found for chronic obstructive pulmonary disease (COPD) mortality and asthma hospital admissions and two-day means (lag 0-1) of UFP (OR: 1.13 [1.01, 1.26] and 1.08 [1.00, 1.16], respectively, per one IQR increase in UFP). Based on 17 years of UFP monitoring data, we present novel findings showing that short-term exposure to UFP can trigger respiratory and cardiovascular diseases mortality and morbidity in Copenhagen, Denmark. The strongest associations with UFP were observed with COPD mortality and asthma hospital admissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)