Search

The impact of early life exposure to residential greenness on childhood rhinitis and its interaction with particulate matter (PM) of different size fractions remain inconsistent. Herein, we recruited 40,486 preschool children from randomly selected daycare centers in 7 cities in China from 2019 to 2020, and estimated exposure to residential greenness by the normalized difference vegetation index (NDVI) with a 500 m buffer. Exposure to ambient PM (PM 1 , PM 2.5, and PM 10 ) was evaluated using a satellite-based prediction model (daily, at a resolution of 1 km × 1 km). By mixed-effect logistic regression, NDVI values during pregnancy, in the first (0-1 year old) and the second (1-2 years old) year of life were negatively associated with lifetime rhinitis (LR) and current rhinitis (CR) (P < 0.001). PM in the same time windows was associated with increased risks of LR and CR in children, with smaller size fraction of PM showing greater associations. The negative associations between prenatal and postnatal NDVI and LR and CR in preschool children remained robust after adjusting for concomitant exposure to PM, whereas the associations of postnatal NDVI and rhinitis showed significant interactions with PM. At lower levels of PM, postnatal NDVI remained negatively associated with rhinitis and was partly mediated by PM (10.0-40.9 %), while at higher levels of PM, the negative associations disappeared or even turned positive. The cut-off levels of PM were identified for each size fraction of PM. In conclusion, prenatal exposure to greenness had robust impacts in lowering the risk of childhood rhinitis, while postnatal exposure to greenness depended on the co-exposure levels to PM. This study revealed the complex interplay of greenness and PM on rhinitis in children. The exposure time window in prenatal or postnatal period and postnatal concomitant PM levels played important roles in influencing the associations between greenness, PM and rhinitis., Competing Interests: Declaration of competing interest None of the authors declares any conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Mounting evidence has linked long- and short-term exposure to particulate air pollution with the incidence and exacerbation of asthma in children, but the biological pathogenesis is unclear. We examined the deposition of particles in the airways of asthmatic children. A planar and symmetric model of airways for 4-year-old asthmatic children was considered. Airflow and particle deposition in the upper (G3-G6) and lower (G9-G12) conducting airways were numerically investigated using computation fluid dynamics (CFD) method. We considered the manifestation of moderate (30% reduction in airway diameter) and severe (60% reduction) asthma. Micron particles (1-10 µm) were considered. We found that particle deposition in the asthmatic children was significantly higher than that in healthy children. The deposition efficiency increased slowly with particle size for healthy children, but increased rapidly for asthmatic children, such that smaller particles could be deposited in the conducting airways of asthmatics. For healthy children, particles were deposited by inertial impaction and gravitational sedimentation respectively in the upper and lower airways, but deposited by inertial impaction in asthmatic children. The severity of the asthma increased the particle deposition in the airways. Our study indicated that asthmatic children were more susceptible to the effect of particulate air pollution. The constricted airways increased the particle deposition by inertial impaction, which may be the biological pathogenesis that causes the hospitalization of asthma in children. Avoiding exposure during air pollution events will be an effective measure to reduce the asthma attack., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019. Published by Elsevier Ltd.)

We studied indoor sources of indoor particulate matter (PM), outdoor air pollution and antibiotic use in relation to asthma, rhinitis and eczema among pre-school children and investigated synergistic effects between PM and antibiotics use. Children (3-6y) from randomly selected day care centres in seven cities across China were included (n = 39,782). Data on ambient temperature and air pollution were collected from local monitoring stations. Data on indoor PM sources (ETS, burning of incense or mosquito coils and biomass for cooking), antibiotics use and health (doctor diagnosed asthma and rhinitis, lifetime eczema, current wheeze and current rhinitis) were assessed by a parental questionnaire. Associations were calculated by multilevel logistic regression. Asthma diagnosis was associated with outdoor temperature, NO 2 and burning mosquito coils. Rhinitis diagnosis was associated with NO 2 , ETS, gas cooking and burning biomass for cooking. Lifetime eczema was associated with temperature, PM 10, NO 2 , ETS, biomass cooking and burning mosquito coils. Burning incense was associated with current wheeze and current rhinitis. Children using antibiotics had more asthma, wheeze, rhinitis, and eczema. Excluding children with respiratory infections did not change associations with antibiotics use. Antibiotics use enhanced the effects of ETS and PM 10 (a synergistic effect). In conclusion, a warmer climate, outdoor NO 2 and PM 10, ETS, gas cooking and burning biomass, incense and mosquito coils can increase the risk of asthma, wheeze, rhinitis and eczema among pre-school children in China. Antibiotics use is a risk factor for childhood asthma, wheeze, rhinitis and eczema and ETS and outdoor PM 10 can enhance the effect., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Few longitudinal studies exist on childhood exposure to indoor and outdoor air pollution and respiratory illness in China. We studied associations between indoor and outdoor environment and prevalence, onset and remission of wheeze and rhinitis among children across China., Methods: Children (3-6 y) were recruited from randomized day care centres in six cities. The main data analysis was restricted to children not moving since birth (N = 17,679). Data on wheeze, rhinitis and the home environment were assessed by a parental questionnaire. Prevalence in the first two years of life (baseline) and the last year (follow-up) was used to calculate onset and remission. Outdoor PM 2.5 , PM 10 , and NO 2 at the day care centre were modelled from monitoring station data. Associations were calculated by multilevel logistic regression., Results: Prenatal NO 2 was associated with decreased remission of wheeze and increased prevalence and increased onset of rhinitis. Prenatal PM 2.5 was associated with increased prevalence of wheeze. Postnatal NO 2 and postnatal PM 10 were associated with increased prevalence and lower remission of wheeze and rhinitis. Mould, window pane condensation, renovation and cockroaches at home were associated with increased prevalence and increased onset of wheeze and rhinitis. Gas cooking was associated with increased onset of rhinitis. Children of mothers with industrial work had more wheeze., Conclusions: Outdoor PM 2.5 , PM 10 and NO 2 can increase childhood wheeze and rhinitis. Dampness and mould can increase onset and decrease remission. Crowdedness, cockroaches at home and emissions from new building materials and gas cooking can be risk factors for wheeze and rhinitis., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The urbanization and industrialization in China is accompanied by bad air quality, and the prevalence of asthma in Chinese children has been increasing in recent years. To investigate the associations between ambient PM 2.5 levels and asthmatic and allergic diseases or symptoms in preschool children in China, we assigned PM 2.5 exposure data from the Global Burden of Disease (GBD) project to 205 kindergartens at a spatial resolution of 0.1° × 0.1° in six cities in China (Shanghai, Nanjing, Chongqing, Changsha, Urumqi, and Taiyuan). A hierarchical multiple logistical regression model was applied to analyze the associations between kindergarten-level PM 2.5 exposure and individual-level outcomes of asthmatic and allergic symptoms. The individual-level variables, including gender, age, family history of asthma and allergic diseases, breastfeeding, parental smoking, indoor dampness, interior decoration pollution, household annual income, and city-level variable-annual temperature were adjusted. A total of 30,759 children (average age 4.6 years, 51.7% boys) were enrolled in this study. Apart from family history, indoor dampness, and decoration as predominant risk factors, we found that an increase of 10 μg/m 3 of the annual PM 2.5 was positively associated with the prevalence of allergic rhinitis by an odds ratio (OR) of 1.20 (95% confidence interval [CI] 1.11, 1.29) and diagnosed asthma by OR of 1.10 (95% CI 1.03, 1.18). Those who lived in non-urban (vs. urban) areas were exposed to more severe indoor air pollution arising from biomass combustion and had significantly higher ORs between PM 2.5 and allergic rhinitis and current rhinitis. Our study suggested that long-term exposure to PM 2.5 might increase the risks of asthmatic and allergic diseases or symptoms in preschool children in China. Compared to those living in urban areas, children living in suburban or rural areas had a higher risk of PM 2.5 exposure., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Otitis media (OM) is a common infection in early childhood with repeated attacks that lead to long-term complications and sequelae, but its risk factors still remain unclear., Objective: To examine the risk of childhood OM for different indoor and outdoor air pollutants during different timing windows, with a purpose to identify critical windows of exposure and key components of air pollution in the development of OM., Methods: We conducted a retrospective cohort study of 1617 children aged 3-4 years in Changsha, China (2011-2012). Children's life-time prevalence of OM and exposure to indoor air pollution related to home renovation activities were surveyed by a questionnaire administered by the parents. Children's exposure to outdoor air pollution, including nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and particulate matter with an aerodynamic diameter ≤ 10 μm (PM 10 ), was estimated using the measured concentrations at municipal monitoring stations. The odds ratio (OR) and 95% confidence interval (CI) of childhood OM for prenatal and postnatal exposure to indoor and outdoor air pollution were examined by using logistic regression model., Results: Life-time prevalence of OM in preschool children (7.3%) was associated not only with prenatal exposure to industrial air pollutant with adjusted OR (95% CI) = 1.44 (1.09-1.88) for a 27 μg/m 3 increase in SO 2 but also with postnatal exposure to indoor renovations with OR (95% CI) = 1.62 (1.05-2.49) for new furniture and 1.81 (1.12-2.91) for redecoration, particularly in girls. Combined exposure to outdoor SO 2 and indoor renovation significantly increased OM risk. Furthermore, we found that exposure to outdoor SO 2 and indoor renovation were significantly associated with the onset but not repeated attacks of OM., Conclusion: Prenatal exposure to outdoor industrial air pollution and postnatal exposure to indoor renovation are independently associated with early childhood OM in China and may cause the OM onset., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Early life is suggested to be a critical time in determining subsequent asthma development, but the extent to which the effect of early-life exposure to ambient air pollution on childhood asthma is unclear., Objectives: We investigated doctor-diagnosed asthma in preschool children due to exposure to ambient air pollution in utero and during the first year of life., Methods: In total 2490 children aged 3-6 years participated in a questionnaire study regarding doctor-diagnosed asthma between September 2011 and January 2012 in China. Children's exposure to critical air pollutants, sulfur dioxide (SO2) as proxy of industrial air pollution, nitrogen dioxide (NO2) as proxy of traffic pollution, and particulate matter≤10µm in diameter (PM10) as a mixture, was estimated from the concentrations measured at the ambient air quality monitoring stations by using an inverse distance weighted (IDW) method. Logistic regression analysis was employed to determine the relationship between early-life exposure and childhood asthma in terms of odds ratio (OR) and 95% confidence interval (CI)., Results: Association between early-life exposure to air pollutants and childhood asthma was observed. SO2 and NO2 had significant associations with adjusted OR (95% CI) of 1.45 (1.02-2.07) and 1.74 (1.15-2.62) in utero and 1.62 (1.01-2.60) and 1.90 (1.20-3.00) during the first year for per 50 µg/m(3) and 15 µg/m(3) increase respectively. Exposure to the combined high level of SO2 and NO2 in China significantly elevated the asthmatic risk with adjusted OR (95% CI) of 1.76 (1.18-2.64) in utero and 1.85 (1.22-2.79) during the first year compared to the low level exposure. The associations were higher for males and the younger children aged 3-4 than females and the older children aged 5-6., Conclusions: Early-life exposure to ambient air pollution is associated with childhood asthma during which the level and source of air pollution play important roles. The high level and nature of combined industrial and traffic air pollution in China may contribute to the recent rapid increase of childhood asthma., (Copyright © 2015 Elsevier Inc. All rights reserved.)

[Display omitted] [ABSTRACT FROM AUTHOR]

Despite mounting evidence linked pneumonia with air pollution, it is unclear what main pollutant(s) exposure in which critical window(s) play a key role in pneumonia. To examine effects of intrauterine and post-natal exposure to air pollution on children's doctor-diagnosed pneumonia (DDP). A combination of cross-sectional and retrospective cohort study was conducted at Changsha, China during 2019–2020. Personal exposure to outdoor air pollutants at each child's home address was estimated using inverse distance weighted (IDW) method based on data from 10 air quality monitoring stations. Associations between personal air pollution exposure and DDP were evaluated. Children's DDP was associated with intrauterine and post-natal exposure to PM 2.5 , PM 2.5–10 , and PM 10 , adjusted ORs (95% CI) of 1.17 (1.04–1.30), 1.09 (1.01–1.17), and 1.07 (1.00–1.14) for IQR increase in intrauterine exposure and 1.12 (1.02–1.22), 1.13 (1.06–1.21), and 1.28 (1.16–1.41) for post-natal exposure. Intrauterine PM 2.5 exposure and post-natal PM 10 exposure were associated with a higher risk of pneumonia. We identified the 2nd trimester, 3rd trimester, and first year as critical windows respectively for PM 2.5 , PM 2.5–10 , and PM 10 exposure. Daytime exposure to traffic-related air pollution especially during early life increased DDP. Intrauterine and post-natal exposure to particulate matters played a dominant role in children's DDP. [Display omitted] • Childhood pneumonia was dominantly affected by particulate matters (PMs) exposure. • Intrauterine exposure to PM 2.5 especially in 2nd trimester enhanced pneumonia risk. • Postnatal exposure PM 10 particularly in first year elevated pneumonia risk. • Daytime was identified as key time for traffic pollution in relation to pneumonia. • Our study supports and develops the hypothesis of 'fetal origin of infection. [ABSTRACT FROM AUTHOR]

Background Pneumonia is a common early-childhood respiratory infection that leads to long-term health impacts, but its risk factors remain unclear. Objective To examine the association between early life exposure to both outdoor and indoor air pollution and childhood pneumonia. Methods We conducted a retrospective cohort study of 2598 children aged 3–6 years in Changsha, China (2011-2012). Children's life-time prevalence of pneumonia and exposure to indoor air pollution related to home renovation were surveyed by a questionnaire answered by the parents. Children's exposure to outdoor air pollution, including nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and particulate matter with an aerodynamic diameter ≤ 10 μm (PM 10 ), was estimated using the measured concentrations at monitoring stations. Association between childhood pneumonia and exposure to indoor and outdoor air pollution during both prenatal and postnatal periods were examined by using logistic regression model in terms of odds ratio (OR) and 95% confidence interval (CI). Results Life-time prevalence of pneumonia in preschool children in Changsha is high, up to 38.6%.We found that childhood pneumonia was associated with postnatal exposure to outdoor particulate air pollutant PM 10 , adjusted OR (95% CI) = 1.26 (1.00–1.57) for per 6 μg/m 3 increase in the concentration. Pneumonia was also associated with postnatal exposure to indoor renovation, adjusted OR (95% CI) = 1.30 (1.02–1.64) for new furniture and 1.30 (1.00–1.69) for redecoration. Combined exposure to outdoor high PM 10 and indoor renovation significantly increased the pneumonia risk. Sensitivity analysis indicated that the association was heterogeneous in different subgroups, but stronger in male and younger children. Conclusion High prevalence of childhood pneumonia in China may be associated with postnatal exposure to ambient particulate air pollution and house renovation. [ABSTRACT FROM AUTHOR]

The urbanization and industrialization in China is accompanied by bad air quality, and the prevalence of asthma in Chinese children has been increasing in recent years. To investigate the associations between ambient PM 2.5 levels and asthmatic and allergic diseases or symptoms in preschool children in China, we assigned PM 2.5 exposure data from the Global Burden of Disease (GBD) project to 205 kindergartens at a spatial resolution of 0.1° × 0.1° in six cities in China (Shanghai, Nanjing, Chongqing, Changsha, Urumqi, and Taiyuan). A hierarchical multiple logistical regression model was applied to analyze the associations between kindergarten-level PM 2.5 exposure and individual-level outcomes of asthmatic and allergic symptoms. The individual-level variables, including gender, age, family history of asthma and allergic diseases, breastfeeding, parental smoking, indoor dampness, interior decoration pollution, household annual income, and city-level variable-annual temperature were adjusted. A total of 30,759 children (average age 4.6 years, 51.7% boys) were enrolled in this study. Apart from family history, indoor dampness, and decoration as predominant risk factors, we found that an increase of 10 μg/m 3 of the annual PM 2.5 was positively associated with the prevalence of allergic rhinitis by an odds ratio (OR) of 1.20 (95% confidence interval [CI] 1.11, 1.29) and diagnosed asthma by OR of 1.10 (95% CI 1.03, 1.18). Those who lived in non-urban (vs. urban) areas were exposed to more severe indoor air pollution arising from biomass combustion and had significantly higher ORs between PM 2.5 and allergic rhinitis and current rhinitis. Our study suggested that long-term exposure to PM 2.5 might increase the risks of asthmatic and allergic diseases or symptoms in preschool children in China. Compared to those living in urban areas, children living in suburban or rural areas had a higher risk of PM 2.5 exposure. [ABSTRACT FROM AUTHOR]

Indoor environment is associated with the sick building syndrome (SBS), but little is known about the contribution of outdoor air pollution and meteorological conditions to SBS. We studied associations between outdoor air pollution, meteorological parameters and selected indoor exposure and building characteristics at home and weekly SBS symptoms in a standardized questionnaire study among 3485 randomly selected adults in China. Outdoor factors included particulate matters with diameter < 10 μm (PM 10 ), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), outdoor temperature (T), relative air humidity (RH), and wind speed (WS) during last three months. Multiple logistic regression was applied calculating odds ratios (OR) with 95% confidence interval (95% CI). Asthma or allergic rhinitis (atopy) was associated with all types of SBS symptoms except fatigue. Indoor factors played a major role in SBS symptoms. Mold/dampness on the floor/ceiling was associated with fatigue OR = 1.60 (1.11–2.30) and headache OR = 1.80 (1.07–3.04). Moldy odor was associated with fatigue OR = 1.59 (1.07–2.37) and dermal symptoms OR = 1.91 (1.21–3.02). Window pane condensation in winter was associated with fatigue OR = 1.73 (1.30–2.31) and throat symptoms OR = 1.53 (1.01–2.31). Damp bed clothing was related with throat symptom OR = 1.62 (1.09–2.40). Home redecoration was associated with fatigue OR = 1.49 (1.07–2.06). Frequent window opening was associated with less nose symptoms OR = 0.54 (0.36–0.82) and mechanical ventilation in the bathroom reduced dermal symptoms OR = 0.66 (0.44–0.99). Females were more susceptible to redecoration and window pane condensation than men. No associations with SBS were observed for outdoor air pollutants or meteorological parameters in the final models combining indoor and outdoor factors, although SO 2 , T, and RH were associated with some SBS symptoms (fatigue, eyes and nose symptoms) in the separate outdoor models. In conclusion, indoor mold/dampness, air pollution from redecoration and poorer ventilation conditions in dwellings can be risk factors for SBS symptoms in an adult Chinese population, especially among females. [ABSTRACT FROM AUTHOR]

Recent rapid increase of childhood asthma in China should be associated with exposure to the high air pollution, but it is unclear to which exposure window, to which kind of air pollution, and to what extent the effect. We investigated the effect of early life exposure to both outdoor and indoor air pollution on childhood asthma. Questionnaire survey was administered to 2490 children aged 3–6 years in Changsha. Early life exposure of each child in utero and during the first year of life was evaluated based on three outdoor air pollutants, i.e. particulate matters (PM 10 ), industry-related SO 2 and traffic-related NO 2 , and two kinds of indoor air pollution represented by new furniture and redecoration. Multivariate logistic regression method was used to estimate the effect of exposure on asthma. Results indicated that exposure to both industry- and traffic-related air pollutants (SO 2 and NO 2 ) significantly increased childhood asthma with odds ratio = 1.07 (95% CI: 1.03–1.12) and 1.16 (1.00–1.35) in utero and 1.09 (1.04–1.15) and 1.26 (1.06–1.50) during the first year for 10 μg/m 3 increase in concentration. Exposure to new furniture and home redecoration during pregnancy significantly increased childhood asthma with odds ratio 2.34 (1.16–4.74) and 2.21 (1.29–3.81) respectively. The effects of outdoor and indoor exposures were independent to each other. We conclude that early life exposures to both outdoor air pollution and indoor renovation contributes to the rapid development of childhood asthma in China, the former stronger after birth but the latter stronger before birth. [ABSTRACT FROM AUTHOR]

Low birth weight (LBW), as a major concern in public health, is now increasing worldwide, but its main indoor environmental factors remain unclear. We examined whether LBW including term-LBW (T-LBW) and preterm-LBW (P-LBW) was associated with maternal exposure to indoor environmental factors, with a purpose to identify the key indoor environmental factor(s) contributing to LBW. A nationwide retrospective cohort study of 30,735 pre-schoolers in six Chinese cities was performed from 2010 to 2012. One questionnaire survey was conducted to collect information on the pre-schoolers' birth outcomes and their maternal exposure of indoor environmental factors including new furniture, house redecoration, cooking fuels, mould/damp stains, and mouldy odour during pregnancy. Maternal exposure of traffic-related air pollutant (NO 2), industrial pollutant (SO 2), and inhalable particulate matter (PM 10), as well as meteorological parameters, was estimated in pregnancy. Associations of LBW, T-LBW and P-LBW with indoor environmental factors were evaluated by two-level (city-child) logistic regression models with an odds ratio (OR) and 95% confidence interval (CI). We found that P-LBW (1.0%) and T-LBW (1.4%) prevalence were respectively associated with persistent mould/damp stains and mouldy odour exposure in utero, ORs = 1.81 (95% CI: 1.01–3.24) and 1.49 (95% CI: 1.01–2.21). Exposure to high temperature and PM 2.5 in pregnancy significantly enhanced the effect of persistent mould/damp stains and/or mouldy odour on P-LBW and LBW, ORs (95% CI) = 2.92 (1.40–6.07) and 1.78 (1.00–3.15) with significant interaction p values of 0.067 and 0.094 respectively. Sensitivity analysis suggested that raising cats and dogs significantly increased LBW risk of persistent mould/damp stains and mouldy odour exposure. Our findings indicate that long-term exposure to indoor mould/damp stains and mouldy odour in utero plays a key role in LBW, and this association can be significantly modified by some specific personal, indoor, and outdoor factors. [Display omitted] • Mould/damp stains exposure was significantly associated with term-low birth weight (LBW). • Maternal exposure to residential mouldy odour significantly increased the risk of preterm-LBW. • High temperature and PM 2.5 enhanced LBW risk of mould/damp stains and mouldy odour. • Families with pets were more susceptible to LBW risk of mould/damp stains and mouldy odour. • Our study has a new implication for the effective reduction and early prevention of LBW. [ABSTRACT FROM AUTHOR]

Few studies focus on the associations of green space composition and configuration with children's allergic rhinitis (AR). A multi-center population-based cross-sectional study was performed in 7 cities in mainland of China between 2019 and 2020, recruiting 36,867 preschool children. Information on the current AR symptoms and demographics were collected by questionnaire. Exposure to residential greenness was estimated by Normalized Difference Vegetation Index (NDVI, 1000 m buffer) around the residences. Greenness composition was estimated in 3 main categories: forest, grassland, shrubland. Configuration of each category and total greenness (a spatial resolution of 10 m × 10 m) was estimated by 6 landscape pattern metrics to quantify their area, shape complexity, aggregation, connectivity, and patch density. Exposure to daily ambient particulate matter (PM 1 , PM 2.5 and PM 10 , a spatial resolution of 1 km × 1 km) was estimated. Multilevel logistic regression models were applied to analyze the associations of greenness and its composition and configuration with AR, and mediation effects by PMs were examined by mediation analysis models. The prevalence of self-reported current AR in preschool children was 33.1%. Two indicators of forest, Aggregation Index of forest patches (AIforest) (odds ratio (OR):0.92, 95% Confidential Interval (CI): 0.88–0.97), and Patch Cohesion of forest (COHESIONforest) (OR: 0.93, 95% CI:0.89–0.98) showed significantly negative associations with AR symptoms. Mediation analyses found the associations were partially mediated by PMs. Age, exclusive breastfeed duration and season were the potential effect modifiers. The associations varied across seven cities. Our findings suggest the inverse associations of the aggregation and connectivity of forest patches surrounding residence addresses with AR symptoms. Since the cross-sectional study only provides associations rather than causation, further studies are needed to confirm our results as well as the underlying mechanisms. • Forest aggregation and connectivity were negatively associated with AR symptoms. • Particulate matters mediated the inverse association of forest configuration with AR. • Age, exclusive breastfeed duration and season were the effect modifiers. [ABSTRACT FROM AUTHOR]

Airborne particulate matter pollution has been linked to occurrence of childhood allergic rhinitis (AR). However, the relationships between exposure to particulate matter with an aerodynamic diameter ≤1 μm (PM 1) during early life (in utero and first year of life) and the onset of childhood AR remain largely unknown. This study aims to investigate potential associations of in utero and first-year exposures to size-segregated PMs, including PM 1 , PM 1–2.5 , PM 2.5 , PM 2.5–10 , and PM 10 , with childhood AR. We investigated 29286 preschool children aged 3–6 years in 7 Chinese major cities during 2019–2020 as the Phase II of the China Children, Families, Health Study. Machine learning-based space-time models were utilized to estimate early-life residential exposure to PM 1 , PM 2.5 , and PM 10 at 1 × 1-km resolutions. The concentrations of PM 1–2.5 and PM 2.5–10 were calculated by subtracting PM 1 from PM 2.5 and PM 2.5 from PM 10 , respectively. Multiple mixed-effects logistic models were used to assess the odds ratios (ORs) and 95% confidence intervals (CIs) of childhood AR associated with per 10-μg/m3 increase in exposure to particulate air pollution during in utero period and the first year of life. Among the 29286 children surveyed (mean ± standard deviation, 4.9 ± 0.9 years), 3652 (12.5%) were reported to be diagnosed with AR. Average PM 1 concentrations during in utero period and the first year since birth were 36.3 ± 8.6 μg/m3 and 33.1 ± 6.9 μg/m3, respectively. Exposure to PM 1 and PM 2.5 during pregnancy and the first year of life was associated with an increased risk of AR in children, and the OR estimates were higher for each 10-μg/m3 increase in PM 1 than for PM 2.5 (e.g., 1.132 [95% CI: 1.022–1.254] vs. 1.079 [95% CI: 1.014–1.149] in pregnancy; 1.151 [95% CI: 1.014–1.306] vs. 1.095 [95% CI: 1.008–1.189] in the first year of life). No associations were observed between AR and both pre- and post-natal exposure to PM 1–2.5 , indicating that PM 1 rather than PM 1–2.5 contributed to the association between PM 2.5 and childhood AR. In trimester-stratified analysis, childhood AR was only found to be associated with exposure to PM 1 (OR = 1.077, 95% CI: 1.027–1.128), PM 2.5 (OR = 1.048, 95% CI: 1.018–1.078), and PM 10 (OR = 1.032, 95% CI: 1.007–1.058) during the third trimester of pregnancy. Subgroup analysis suggested stronger PM-AR associations among younger (<5 years old) and winter-born children. Prenatal and postnatal exposures to ambient PM 1 and PM 2.5 were associated with an increased risk of childhood AR, and PM 2.5 -related hazards could be predominantly attributed to PM 1. These findings highlighted public health significance of formulating air quality guideline for ambient PM 1 in mitigating children's AR burden caused by particulate air pollution. • The first study evaluated early-life exposure to ambient PM 1 and childhood AR. • Increased childhood AR risk associated with prenatal and postnatal exposures to ambient PM 1 and PM 2.5. • Later trimesters of gestation might be the sensitive window for early-life PM exposure and childhood AR. • Enhanced effect of early-life PM exposure on childhood AR was observed among younger and winter-born children. [ABSTRACT FROM AUTHOR]