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Background: Prelabor rupture of the fetal membranes (PROM) is a major contributor to adverse perinatal outcomes. Some epidemiologic studies explored the association between maternal PM 2.5 exposure and PROM but failed to treat the labor induction and prelabor cesarean section as censored observations., Objective: We aimed to evaluated whether acute and chronic maternal ambient PM 2.5 exposure may increase the risk of PROM in China., Methods: This study was based on the China Labor and Delivery Survey, a nationwide multicenter investigation. Included in the current analysis were 45,879 singleton spontaneous births in 96 hospitals in mainland China from 2015 to 2017. Outcomes were PROM, preterm PROM (<37 weeks' gestation) and term PROM (≥37 weeks' gestation). Daily concentration of PM 2.5 at 1 km spatial resolution was estimated by gap-filling model. Generalized linear mixed model and mixed effects Cox model were applied to assess the associations of acute (from 0 to 4 days before delivery) and chronic (average gestational and trimester-specific) ambient PM 2.5 exposure with outcomes, respectively., Results: Significant associations were found between acute PM 2.5 exposures (per interquartile range increase) and the risk of preterm PROM (OR = 1.11; 95 % CI: 1.03, 1.19 for PM 2.5 on delivery day; OR = 1.10; 95 % CI: 1.02, 1.18 for PM 2.5 1 day before delivery) but not for term PROM. An interquartile range increase in PM 2.5 during the second trimester was associated with elevated risks of PROM (HR = 1.14; 95 % CI: 1.07, 1.22), preterm PROM (HR = 1.22; 95 % CI: 1.02, 1.45) and term PROM (HR = 1.13; 95 % CI: 1.06, 1.22), respectively. Women who were less educated, obese, or gave birth in a cold season appeared to be more sensitive to ambient PM 2.5 exposure., Conclusion: Our findings suggest that both acute and chronic maternal exposures to ambient PM 2.5 during pregnancy are risk factors for PROM., 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 © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Fine particulate matter (PM 2.5 ) exposure has been reported to adversely affect birth outcomes, but the evidence is limited, particularly in low- and middle-income countries (LMICs). We assessed the associations between maternal PM 2.5 exposure and low birth weight (LBW) and preterm birth (PTB) in Africa., Methods: We used standard Demographic and Health Surveys (DHS) data (2005-2015) from 15 countries in Africa to conduct a cross-sectional study. The study population was composed of 131,594 births with detailed information on maternal and household variables. LBW was defined as a birth weight of < 2500 g after 37 weeks, and PTB was defined as live birth occurring before 37 weeks of gestation. Average exposure to PM 2.5 during pregnancy was estimated using satellite-based models. Multivariable logistic regression models were constructed, and analyses of data by region (Western, Eastern, Central, and Southern Africa) and data stratified by potential effect modifiers were conducted., Results: A total of 13,214 (10%) LBW and 4,377 (3.3%) PTB cases were identified. An interquartile range (IQR) (33.9 μg/m 3 ) increase in PM 2.5 during pregnancy was associated with increased odds of LBW and PTB, with odds ratios (ORs) of 1.28 (95% CI: 1.23, 1.34) and 1.08 (95% CI: 1.01, 1.16), respectively. Region-specific analyses revealed significant associations between PM 2.5 and LBW in all regions, and significant associations between PM 2.5 and PTB in Western and Southern Africa. Subgroup analyses revealed that the association between PM 2.5 and LBW was present in all subgroups, and stronger associations were observed in female infants, while the association between PM 2.5 and PTB was larger in subgroups of older individuals living in urban areas., Conclusion: This multicountry study in Africa demonstrated significant associations between maternal exposure to PM 2.5 and higher odds of LBW and PTB. Our findings may facilitate air quality control strategies that address adverse birth outcomes in LMICs., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Non-invasive bio-samples, such as saliva and urine, are promising tools for assessment of inflammation and oxidative stress biomarkers. Few studies have investigated potential responses of those biomarkers towards short-term PM 2.5 exposure. We conducted a longitudinal study with 4 repeated examinations among 40 healthy, nonsmoking adults in Shanghai, China. Personal samplings were performed for PM 2.5 exposure assessment. Then, five biomarkers, including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), alpha-1 antitrypsin (A1AT) in saliva and 8-Iso-Prostaglanding F 2α (8-iso-PGF 2α ), total antioxidant capacity (TAC) in urine, were measured. We fitted linear mixed-effect models to evaluate short-term effect of personal PM 2.5 exposure on salivary and urinary biomarkers, adjusting for potential confounders of meteorology, sociodemographic characteristics and biomarker detection. We also explored sensitive time windows of exposure for different biomarkers. We found robust associations of salivary CRP, TNF-α, and urinary 8-iso-PGF 2α with PM 2.5 exposure, and responses of salivary inflammatory markers occurred more acutely than urinary oxidative stress markers. For instance, a 10 μg/m 3 increase in PM 2.5 was associated with an elevation of 5.49% (95% CI: 1.17%, 9.99%) in CRP and 7.05% (95% CI: 1.29%, 13.13%) in TNF-α both at lag 12 h, and 6.97% (95% CI: 1.33%, 12.92%) in 8-iso-PGF 2α at lag 01 d. Based on non-invasive samples, this study provided evidence on effect of PM 2.5 exposure on responses of systematic inflammation and oxidative stress. Sub-daily (6-12 h) and daily (≥24 h) period after PM 2.5 exposure might be sensitive time window to detect the responses of salivary (i.e. CRP, TNF) and urinary biomarkers (i.e. 8-iso-PGF 2α ), respectively., 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 © 2021 Elsevier Ltd. All rights reserved.)

This study aims to explore the relationship between ambient NO 2 levels and the transmission ability (basic reproductive number, R 0 ) of COVID-19 in 63 Chinese cities. After adjustment for temperature and relative humidity, R 0 was positively associated with NO 2 concentration at city level. The temporal analysis within Hubei province indicated that all the 11 Hubei cities (except Xianning City) had significant positive correlations between NO 2 concentration (with 12-day time lag) and R 0 (r > 0.51, p < 0.005). Since the association between ambient NO 2 and R 0 indicated NO 2 may increase underlying risk of infection in the transmission process of COVID-19. In addition, NO 2 is also an indicator of traffic-related air pollution, the association between NO 2 and COVID-19's spreadability suggest that reduced population movement may have reduced the spread of the SARS-CoV-2., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Limited evidence is available for the associations between fine particulate matter (PM 2.5 ) constituents and daily cardiovascular disease (CVD) mortality in China. In present study, a time-series analysis was conducted to evaluate the associations of PM 2.5 constituents (two carbonaceous fractions, eight water-soluble inorganic ions and fifteen elements) with daily CVD mortality in Pudong New Area of Shanghai, China, from 2014 to 2016. Results showed that the effect estimates for the associations of PM 2.5 and its constituents with CVD mortality were generally strongest when using the exposures of the previous two day concentrations. The associations of organic carbon, sulfate, ammonia, potassium, copper, arsenic, and lead with daily CVD mortality were robust to the adjustment of PM 2.5 total mass, their collinearity with PM 2.5 total mass, and criteria gaseous air pollutants. An interquartile range increase in the previous two day concentrations of PM 2.5 , organic carbon, sulfate, ammonia, potassium, copper, arsenic, and lead were associated with significant increments of 2.21% (95% confidence interval [95%CI]: 0.54%, 3.88%), 2.83% (95% CIs: 1.16%, 4.50%), 1.90% (95% CIs: 0.35%, 3.45%), 2.29% (95% CIs: 0.80%, 3.77%), 0.94% (95% CIs: 0.13%, 1.75%), 1.53% (95% CIs: 0.37%, 2.69%), 2.08% (95% CIs: 0.49%, 3.68%) and 1.98% (95% CIs: 0.49%, 3.47%) in daily CVD mortality, respectively, in single-pollutant models. In conclusion, this study suggested that organic carbon, sulfate, ammonia, potassium, copper, arsenic, and lead might be mainly responsible for the associations between short-term PM 2.5 exposures and increased CVD mortality in Shanghai, China., Competing Interests: Declaration of competing interest The authors declared no conflicts of interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Systemic inflammation is considered one of the key mechanisms in the development of cardiovascular diseases induced by fine particulate matter (PM 2.5 ) air pollution. However, evidence concerning the effects of various PM 2.5 constituents on circulating inflammatory biomarkers were limited and inconsistent., Objectives: To evaluate the associations of short-term exposure to a variety of PM 2.5 constituents with circulating inflammatory biomarkers., Methods: We conducted a panel study from May to October 2016 among 40 healthy adults in Shanghai, China. We monitored the concentrations of 27 constituents of PM 2.5 . We applied linear mixed-effect models to analyze the associations of PM 2.5 and its constituents with 7 inflammatory biomarkers, and further assessed the robustness of the associations by fitting models adjusting for PM 2.5 mass and/or their collinearity. Benjamini-Hochberg false discovery rate was used to correct for multiple comparisons., Results: The associations of PM 2.5 were strongest at lag 0 d with tumor necrosis factor-α (TNF-α), at lag 1 d with interleukin-6, interleukin-8, and interleukin-17A, at lag 02 d with monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). After correcting for multiple comparisons in all models, Cl - , K + , Si, K, As, and Pb were significantly associated with interleukin-8; SO 4 2 - and Se were marginally significantly associated with interleukin-8; SO 4 2 - , As, and Se were marginally significantly associated with TNF-α; and Si, K, Zn, As, Se, and Pb were marginally significantly associated with MCP-1., Conclusions: Our results suggested that some constituents (SO 4 2 - , Cl - , K + , and some elements) might be mainly responsible for systemic inflammation triggered by short-term PM 2.5 exposure., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Prenatal exposure to ambient levels of air pollution has been reported to adversely affect birth outcomes, yet few studies have investigated refined susceptible windows for adverse birth outcomes., Objectives: The study aimed at estimating associations between maternal exposure to ambient fine particulate matter (PM 2.5; particles with an aerodynamic diameter ≤ 2.5 μm) and birth outcomes, including birth weight, low birth weight (LBW) and preterm birth (PTB), and identify specific susceptible windows., Methods: A total of 3692 singleton live births were enrolled between 2013 and 2016 in Shanghai Birth Cohort, China. Based on mothers' residential addresses, weekly mean concentrations of PM 2.5 over gestation were estimated based on an incorporated evaluating approach combining satellite-based estimates and ground-level measurements. Distributed lag non-liner models (DLNMs) were fitted by incorporating with multiple liner models and Cox proportional hazard models to evaluate weekly-as well as trimester-exposure-lag-response associations between average PM 2.5 level and birth weight, LBW and PTB, and to identify critical windows., Results: In this study, gestational exposure to PM 2.5 was associated with adverse birth outcomes in infants, and critical windows were identified as 31st-34th gestational weeks for reduced birth weight, 38th-42 nd weeks for LBW and 27th-30th weeks for PTB, respectively. Trimester-specific associations were found for all birth outcomes during the third trimester., Conclusions: Ambient PM 2.5 exposure exhibited adverse impacts on multiple outcomes including reduced birth weight, LBW and PTB in the late pregnancy. The study provides further evidence supporting harmful effects of maternal PM 2.5 exposure on birth outcomes and identifying critical windows., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: The identification of constituents of fine particulate matter (PM 2.5 ) air pollution that had key impacts of ischemic stroke (the predominant subtype of stroke) is important to understand the underlying biological mechanisms and develop air pollution control policies., Objectives: To explore the associations between PM 2.5 constituents and hospitalization for ischemic stroke in Shanghai, China., Methods: We conducted a time-series study to explore the associations between 27 constituents of PM 2.5 and hospitalization for ischemic stroke in Shanghai, China from 2014 to 2016. The over-dispersed generalized additive models with adjustment for time, day of week, holidays, and weather conditions were used to estimate the associations. We also evaluated the robustness of the effect estimates for each constituent after adjusting for the confounding effects of PM 2.5 total mass and gaseous pollutants and the collinearity (the residual) between this constituent and PM 2.5 total mass. We also compared the associations between seasons., Results: In total, we identified 4186 ischemic stroke hospitalizations during the study period. The associations of ischemic stroke were consistently significant with elemental carbon and several elemental constituents (Chromium, Iron, Copper, Zinc, Arsenic, Selenium, and Lead) at lag 1 day in single-constituent models, models adjusting for PM 2.5 total mass or gaseous pollutants and models adjusting for collinearity. The associations were much stronger in cool season than in warm season., Conclusions: The current study provides suggestive evidence that elemental carbon and some metallic elements may be mainly responsible for the risks of ischemic stroke hospitalization induced by short-term PM 2.5 exposure., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Fine particulate matter (PM 2.5 ) has been widely associated with airway inflammation represented by increased fractional concentration of exhaled nitric oxide (FeNO). However, it remains unclear whether various PM 2.5 constituents have different impacts on FeNO and its production process from the arginase (ARG)-nitric oxide synthase (NOS) pathway., Objectives: To investigate the acute effects of PM 2.5 constituents on FeNO and DNA methylation of genes involved., Methods: We conducted a longitudinal panel study among 43 young adults in Shanghai, China from May to October in 2016. We monitored the concentrations of 25 constituents of PM 2.5 . We applied the linear mixed-effect model to evaluate the associations of PM 2.5 constituents with FeNO and DNA methylation of the ARG2 and NOS2A genes., Results: Following PM 2.5 exposure, NOS2A methylation decreased and ARG2 methylation increased only on the concurrent day, whereas FeNO increased most prominently on the second day. Nine constituents (OC, EC, K, Fe, Zn, Ba, Cr, Se, and Pb) showed consistent associations with elevated FeNO and decreased NOS2A methylation or increased ARG2 methylation in single-constituent models and models adjusting for PM 2.5 total mass and collinearity. An interquartile range increase of these constituents was associated with respective decrements of 0.27-1.20 in NOS2A methylation (%5mC); increments of 0.48-1.56 in ARG2 methylation (%5mC); and increments of 7.12%-17.54% in FeNO., Conclusions: Our results suggested that OC, EC, and some metallic elements may be mainly responsible for the development and epigenetic regulation of airway inflammatory response induced by short-term PM 2.5 exposure., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Maternal exposure to ambient fine particulate matter (PM 2.5) during pregnancy has been associated with impaired neurobehavioral development in children. However, the specific mechanism remains unclear. Brain derived neurotrophic factor (BDNF) is an important growth factor in the nervous system. We evaluated the associations of maternal PM 2.5 exposures with fetal BDNF in the umbilical cord blood in a prospective cohort study. A total of 711 eligible mother-infant pairs from the Shanghai Birth Cohort were included in the current study. Daily maternal exposures to ambient PM 2.5 were assessed with a gap-filling approach at 1 * 1 km2 resolution based on self-reported home addresses. The concentrations of BDNF in the cord blood were measured by ELISA. A linear regression model was applied to evaluate the association of maternal ambient PM 2.5 exposure with fetal BDNF level at birth. The median concentration of BDNF was 13,403 pg/ml. Vaginal deliveries and female infants had higher BDNF levels than cesarean deliveries and male infants. One natural log (ln) unit increase in maternal PM 2.5 exposure during the second trimester was significantly associated with − 0.20 (95% CI: −0.36, −0.05) ln-unit decrease in BDNF level in all births. These effects were stronger and more significant in vaginal deliveries and in male infants. Our study suggests that BDNF in the cord blood may serve as a potential biomarker in assessing the neurodevelopmental effects of maternal PM 2.5 exposure. • Limited evidence is available on maternal PM 2.5 exposures and fetal BDNF levels. • Maternal PM 2.5 exposure was negatively associated with fetal BDNF level at birth. • Delivery modes and infant sex may modify the association. [ABSTRACT FROM AUTHOR]

Exposure to fine particulate matter (PM 2.5) during pregnancy has been linked to the risk of gestational diabetes mellitus (GDM), while conclusions are inconsistent. In this study we aimed to estimate the effects of prenatal PM 2.5 exposure with blood glucose in early pregnancy and the GDM risk. Participants were recruited from the SH-IPMCH-BTH cohort (n = 41,929), a study of air pollution and birth outcome. All participants provided serum samples for analyses of fasting blood glucose (FBG) and HbA1c during early pregnancy. GDM was diagnosed using an oral glucose tolerance test (OGTT) with the time interval of 1 h. Prenatal exposure to PM 2.5 was estimated using gap-filled satellite exposure assessments in Shanghai, China. Both FBG and HbA1c levels were significantly and positively associated with PM 2.5 exposure during early pregnancy. A 10 μg/m3 increase of PM 2.5 exposure from early to middle pregnancy was associated with the risk of GDM (first trimester OR=1.09, 95% CI: 1.02, 1.16; second trimester OR=1.09, 95% CI: 1.03, 1.16; first two trimester OR=1.15, 95%CI: 1.04, 1.28). The combined effects were greater among elevated FBG and HbA1c women with higher PM 2.5 exposure in middle trimester (P for interaction=0.037 and 0.001, respectively). This study found that exposure to PM 2.5 exposure in the 1st and 2nd trimesters was related to GDM. FBG and HbA1c played roles in the relationship between PM 2.5 exposure in the 2nd trimester and GDM. [Display omitted] • PM 2.5 exposure in early trimester is associated with blood glucose impairment. • Higher early- and middle- pregnancy PM 2.5 exposure is associated with GDM. • FBG and HbA1c are effect modifiers of PM 2.5 exposure in the second trimester and GDM. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) is the most important air pollution problem that leads to substantial health effects. However, very few studies focused on the effects of ultrafine particles (UFPs, particles< 0.1 μm) on children respiratory health. We performed a panel study with 3 rounds of follow-up among 65 pupils at the Elementary School Affiliated to Shanghai Normal University in China from November 2018 to June 2019. Real-time concentrations of UFPs were measured in the campus. In each visit, we detected biomarkers in saliva and microflora in buccal mucosa, fractional exhaled nitric oxide (FeNO) and lung function. We applied a linear mixed-effect (LME) model to examine the associations of UFPs and each health outcome. We found increased levels of FeNO and tumor necrosis factor-α (TNF-α) and reduced lung function in association with higher UFP exposure. For each interquartile range increase of UFPs, the largest changes were found in lag 0–72 h for forced vital capacity [-69.02 ml (95% CI: −114.20, −23.84)], TNF-α [13.41 pg/ml (95% CI: 7.08, 19.73)], and FeNO [26.85% (95% CI: 11.84%, 43.88%)]. UFP exposure was associated with reduced diversity in buccal microflora with largest reduction in lag 0–72 h [12.24 (95% CI: 7.76, 16.71) for Ace index; 8.78 (95% CI: 2.96, 14.60) for Chao1 index]. UFP exposure was also associated with increased Streptococcus, Gemella, and decreased Actinomyces. Short-term UFP exposures may impair the respiratory system by inducing inflammation, decreasing lung function and attenuating buccal microbe diversity in children. Image 1 • Few epidemiological studies explored the respiratory effects of UFPs in children. • Short-term UFP exposure may reduce lung function and induce airway inflammation. • UFPs may increase oral inflammation and attenuate buccal microflora diversity. [ABSTRACT FROM AUTHOR]

Accurate individual exposure assessment is crucial for evaluating the health effects of particulate matter (PM). Various portable monitors built upon low-cost optical sensors have emerged. However, the main challenge for their application is to guarantee accuracy of measurements. To assess the performance of a newly developed PM sensor, and to develop methods for post-hoc data calibration to optimize its data quality. We conducted a series of laboratory experiments and field evaluations to quantify the reproducibility within Plantower PM sensors 7003 (PMS 7003) and the consistency between sensors and two established PM 2.5 measurement methods [tapered element oscillating microbalances (TEOM) and gravimetric method (GM)]. Post-hoc data calibration methods for sensors were based on a multiple linear regression model (MLRM) and a random forest model (RFM). Ratios of raw and calibrated readings over the data of reference methods were calculated to examine the improvement after calibration. Strong correlations (≥0.82) and relatively small relative standard deviations (16–21%) between sensors were found during the laboratory and the field sampling. Compared with the reference methods, moderate to strong coefficients of determination (0.56–0.83) were observed; however, significant deviations were presented. After calibration, the ratios of PMS measurements over that of two reference methods both became convergent. Our study validated low-cost optical PM sensors under a wide range of PM 2.5 concentrations (8–167 μg/m3). Our findings indicated potential applicability of PM sensors in PM 2.5 exposure assessment, and confirmed a need of calibration. Linear calibration methods may be sufficient for ambient monitoring using TEOM as a reference, while nonlinear calibration methods may be more appropriate for indoor monitoring using GM as a reference. • We evaluated the performance of a low-cost optical particle matter sensor. • Sensitivity to potential source and high reproducibility within sensors were found. • Multiple linear regression and random forest models were developed for calibration. • Careful calibration ensures confident use of PMS 7003 in exposure assessment. [ABSTRACT FROM AUTHOR]

• Satellite-based and chemical transport modelling products were applied in this study. • It's the first to establish the mediation model of PM 2.5 , PROM and gestational age. • PROM mediated the relationship between PM 2.5 exposure and gestational age. • Preconception exposure to PM 2.5 and components were considered in this research. The associations between maternal exposure to fine particles with aerodynamic diameter ≤ 2.5 μm (PM 2.5) and gestational age as well as premature rupture of membranes (PROM) remain unclear. Few studies have focused on preconception exposure and components of fine particles in China. A total of 1715 pregnant women were enrolled at hospitals affiliated with Nanjing Medical University from 2014 to 2015. Personal exposure to PM 2.5 was estimated from preconception to the first trimester. Gestational age and PROM were investigated to explore their associations with PM 2.5 and its components. From 12 weeks before conception to the end of the first trimester, the gestational age was reduced by 0.89 days (95% CI: −1.37, −0.40) per 10 μg/m3 increment in PM 2.5 exposure. After the exposure period was separated into two groups, PM 2.5 exposure reduced the gestational age by 0.35 days (95% CI: −0.59, −0.11) in the 12 weeks before pregnancy. With maternal exposure to PM 2.5 early in the first trimester, gestational age was reduced by 0.62 days (95% CI: −1.09, −0.14). After mediation analysis, we found that PROM mediated the association between PM 2.5 and gestational age from preconception to the first trimester. Components analysis indicated that exposure to black carbon, organic matter, and nitrate increased the risk of PROM and decreased gestational age. Exposure to PM 2.5 as well as some components of PM 2.5 before and during early pregnancy was associated with PROM and gestational age. PROM might be a potential mediator in associations between PM 2.5 as well as various components and gestational age. [ABSTRACT FROM AUTHOR]

• Entrained-flow gasification coal fine slag can be upgraded by ultrasonic flotation. • Ultrasonic flotation perfect index (η) is 12.60% higher than conventional flotation. • The ash content of ultrasonic flotation concentrates is as low as 27.11%. • Ultrasonic emulsification improved the stability of bubbles in flotation. Entrained-flow gasification coal fine slag is a low value and difficult-to-separate solid waste. In this work, ultrasonic flotation experiments are adopted to enrich the residual carbon and are compared to conventional flotation. The concentrate yield and concentrate ash content decrease by 9.94% and 16.54%, respectively, with the flotation perfect index 12.60% higher. Scanning electron microscopy/energy-dispersive X-ray spectroscopy and thermogravimetric analysis show that the ultrasonic flotation has a positive effect on the residual carbon enrichment. Furthermore, the wet screening results prove that the ultrasonic flotation has a more significant crushing effect on the entrained-flow gasification coal fine slag particles than conventional flotation, mainly benefitting the flotation of small particles (i.e. 0.15–0 mm size fractions). Moreover, after ultrasonic emulsification, the collector can be dispersed more evenly and the surface tension of the collector-deionized water system is decreased, which is beneficial to improving the selectivity of the collector. In addition, with ultrasonic pretreatment at 180 W for 4 min in pulp and emulsification at 180 W for 20 s in the collector-deionized water system, the bubbles in the froth layer are the smallest and most stable, and the merging of the bubbles becomes less obvious. [ABSTRACT FROM AUTHOR]

Background: Short-term exposure to ambient air pollution has been linked with daily hospitalization and mortality from acute coronary syndrome (ACS); however, the associations of subdaily (hourly) levels of criteria air pollutants with the onset of ACS and its subtypes have rarely been evaluated.Methods: We conducted a time-stratified case-crossover study among 1 292 880 patients with ACS from 2239 hospitals in 318 Chinese cities between January 1, 2015, and September 30, 2020. Hourly concentrations of fine particulate matter (PM2.5), coarse particulate matter (PM2.5-10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3) were collected. Hourly onset data of ACS and its subtypes, including ST-segment-elevation myocardial infarction, non-ST-segment-elevation myocardial infarction, and unstable angina, were also obtained. Conditional logistic regressions combined with polynomial distributed lag models were applied.Results: Acute exposures to PM2.5, NO2, SO2, and CO were each associated with the onset of ACS and its subtypes. These associations were strongest in the concurrent hour of exposure and were attenuated thereafter, with the weakest effects observed after 15 to 29 hours. There were no apparent thresholds in the concentration-response curves. An interquartile range increase in concentrations of PM2.5 (36.0 μg/m3), NO2 (29.0 µg/m3), SO2 (9.0 µg/m3), and CO (0.6 mg/m3) over the 0 to 24 hours before onset was significantly associated with 1.32%, 3.89%, 0.67%, and 1.55% higher risks of ACS onset, respectively. For a given pollutant, the associations were comparable in magnitude across different subtypes of ACS. NO2 showed the strongest associations with all 3 subtypes, followed by PM2.5, CO, and SO2. Greater magnitude of associations was observed among patients older than 65 years and in the cold season. Null associations of exposure to either PM2.5-10 or O3 with ACS onset were observed.Conclusions: The results suggest that transient exposure to the air pollutants PM2.5, NO2, SO2, or CO, but not PM2.5-10 or O3, may trigger the onset of ACS, even at concentrations below the World Health Organization air quality guidelines. [ABSTRACT FROM AUTHOR]

Background: Few studies have evaluated the health benefits of omega-3 fatty acid supplementation against fine particulate matter (aerodynamic diameter <2.5 μm [PM2.5]) exposure in highly polluted areas.Objectives: The authors sought to evaluate whether dietary fish-oil supplementation protects cardiovascular health against PM2.5 exposure in China.Methods: This is a randomized, double-blinded, and placebo-controlled trial among 65 healthy college students in Shanghai, China. Participants were randomly assigned to either the placebo group or the intervention group with dietary fish-oil supplementation of 2.5 g/day from September 2017 to January 2018, and received 4 rounds of health examinations in the last 2 months of treatments. Fixed-site PM2.5 concentrations on campus were measured in real time. The authors measured blood pressure and 18 biomarkers of systematic inflammation, coagulation, endothelial function, oxidative stress, antioxidant activity, cardiometabolism, and neuroendocrine stress response. Acute effects of PM2.5 on these outcomes were evaluated within each group using linear mixed-effect models.Results: The average PM2.5 level was 38 μg/m3 during the study period. Compared with the placebo group, the fish-oil group showed relatively stable levels of most biomarkers in response to changes in PM2.5 exposure. Between-group differences associated with PM2.5 exposure varied by biomarkers and by lags of exposure. The authors observed beneficial effects of fish-oil supplementation on 5 biomarkers of blood inflammation, coagulation, endothelial function, oxidative stress, and neuroendocrine stress response in the fish-oil group at a false discovery rate of <0.05.Conclusions: This trial shows that omega-3 fatty acid supplementation is associated with short-term subclinical cardiovascular benefits against PM2.5 exposure among healthy young adults in China. (Effect of Dietary Supplemental Fish Oil in Alleviating Health Hazards Associated With Air Pollution; NCT03255187). [ABSTRACT FROM AUTHOR]

[Display omitted] • 19 clinical or subclinical cardiovascular indicators were evaluated in 15 cities. • PM 2.5 may induce diverse early cardiovascular injuries within a week. • Injuries include inflammation, endothelial function and hemodynamic changes. Although previous studies have linked short-term exposure to fine particulate matter (PM 2.5) air pollution with various molecular biomarkers of cardiovascular system, limited evidence is available for indicators at clinical or subclinical levels. We examined the associations between short-term PM 2.5 exposure and a range of clinical or subclinical indicators of cardiovascular health in general population. A longitudinal repeated-measure study was conducted among 247,640 participants who repeatedly visited health examination centers in 15 typical cities across China from 2013 to 2020. A total of 19 well-established indicators of cardiovascular risk or injury were evaluated and air quality data at nearest fixed-site monitors were collected. Linear mixed-effects models with distributed lag models were used to analyze the potentially lagged effects of PM 2.5. The average daily PM 2.5 concentration was 48 μg/m3 during the study period. PM 2.5 exposure was associated with significant changes of 16 indicators with the effects generally peaked on lag 0 to 3 day. For an interquartile range (IQR) elevation (37 μg/m3) in PM 2.5 concentrations over lag 0–7 day, the cumulative percentage changes were 0.50% to 1.27% in heart rates and blood pressure, 0.10% to 5.04% in inflammatory markers, −0.29% to 1.39% in blood viscosity parameters, −0.67% to 3.45% in blood lipids, 0.89% in blood homocysteine, 0.13% to 0.78% in myocardial enzymes, and 3.03% in pulse wave velocity. These associations were not substantially changed after adjusting concomitant exposures to gaseous pollutants. Short-term exposure to PM 2.5 may induce early cardiovascular effects in general population, including acute inflammation, myocardial injury, increased blood viscosity, vascular stiffness and hyperlipidemia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Exposure to PM 2.5 increased CVD mortality in a nationally representative cohort. • We provided one of the very few evidence on long-term CVD effects of PM 2.5 constituents. • BC, OM, NO 3 –, NH 4 + and SO 4 2− showed appreciably larger risks than PM 2.5 total mass. • Soil dust showed no cardiovascular risks. Few studies have evaluated long-term cardiovascular effects of fine particulate matter (PM 2.5) and its constituents in countries with high air pollution levels. We aimed to investigate the associations of long-term exposure to PM 2.5 and constituents with cardiovascular mortality in China. We conducted a prospective cohort study of 90,672 adults ≥ 18 years from 2010 to 2017 in 161 districts/counties across China. The residential annual-average exposure to PM 2.5 and 6 main components from 2011 to 2017 were estimated by satellite-based and chemical transport models. Associations of PM 2.5 and constituents with cardiovascular mortality were analyzed by competing-risk Cox proportional hazards regression. The average PM 2.5 exposure throughout the whole period was 46 ± 22 μg/m3. The hazard ratios of mortality (95% confidence intervals) per 10 μg/m3 increase in PM 2.5 concentrations were 1.02 (1.00, 1.05) for overall cardiovascular disease, 1.05 (1.01, 1.09) for ischemic heart disease, 1.03 (1.00, 1.06) for overall stroke, 0.99 (0.94, 1.04) for hemorrhagic stroke, and 1.11 (1.04, 1.19) for ischemic stroke. PM 2.5 constituents from fossil fuel combustion (i.e., black carbon, organic matter, nitrate, ammonium, and sulfate) showed larger hazard ratios than PM 2.5 total mass, while soil dust showed no risks. This nationwide cohort study demonstrated associations of long-term exposure to PM 2.5 and its constituents with increased risks of cardiovascular mortality in the general population of China. Our study highlighted the importance of PM 2.5 constituents from fossil fuel combustion in the long-term cardiovascular effects of PM 2.5 in China. [ABSTRACT FROM AUTHOR]

Potential hazards of fine particulate matter (PM 2.5) constituents on preterm birth (PTB) have rarely been explored in China. To quantify the associations of PM 2.5 constituents with PTB. This study was based on a nationwide cohort of 3,723,169 live singleton births delivered between January 2010 and December 2015 in China. We applied satellite-based estimates of 5 PM 2.5 constituents (organic carbon; black carbon; sulfate; ammonium; and nitrate). We used Cox proportional hazards regression models adjusted for individual covariates, temperature, humidity, and seasonality to evaluate the associations. During the entire pregnancy, each interquartile range (29 μg/m3) increase in PM 2.5 concentrations was associated with a 7% increase in PTB risk [hazard ratio (HR): 1.07; 95% confidence interval (CI): 1.07–1.08). We observed the largest effect estimates on carbonaceous components (HR: 1.09; 95% CI: 1.08–1.10 for organic carbon and black carbon). Early pregnancy appeared to be the critical exposure window for most constituents. Women who were older, exposed to second-hand smoke, overweight or obese before pregnancy, conceived during winter, and living in northern China or rural areas were more susceptible. Carbonaceous components of PM 2.5 were associated with higher PTB risk. Findings on characteristics of vulnerability underlined targeted protections on susceptible subgroups. [Display omitted] • The largest study to evaluate the hazards of PM 2.5 chemical constituents on PTB. • Carbonaceous components of PM 2.5 may play crucial roles in the PM 2.5 -associated PTB. • Early pregnancy is a critical exposure time window for preterm birth prevention. • Women aged ≥30 yrs, exposed to second-hand smoke, with higher BMI were more susceptible. [ABSTRACT FROM AUTHOR]

• A 10 wt% SiC-reinforced AlSi10Mg-based composites with higher density is prepared by selective laser melting. • Al4SiC4 phase forms because the in situ reaction between SiC and Al melt occurs. • The SLM-fabricated AlSi10Mg-10SiC composite (90.64 J/mm3) displays the high yield strength (408 Mpa) and modulus (90 Gpa). In this study, a 10 wt% SiC-reinforced AlSi10Mg-based composites is prepared by selective laser melting (SLM) process. The effect of laser linear energy density on phase morphology, microstructure, and mechanical properties of AlSi10Mg-10SiC composite is investigated. There is relatively higher density, no obvious pores and cracks in the SLM-fabricated AlSi10Mg-10SiC composites with laser linear energy densities ranging from 90.64 J/mm3 to 104.16 J/mm3. The high laser linear energy density promotes the in-situ reaction between SiC particle and Al melt in the melt pool, the Al4SiC4 phase forms during SLM fabrication process. Driven by Marangoni convection, the fine SiC particles and Al4SiC4 phase distributes uniformly. When the laser linear energy density is 104.16 J/mm3, the composite exhibits the highest average microhardness of 208.5 HV 0.1. When the laser linear energy density is 90.64 J/mm3, the composite displays the highest yield strength and modulus with values of 408 MPa and 90 Gpa, respectively. During the deformation process of tensile test, the higher modulus SiC particles could withstand greater load transfer, which improves the modulus and yield strength of the composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Limited evidence on short-term exposure to PM 2.5 and under-5 mortality in China. • A national case-crossover study and use of satellite-based exposure model. • PM 2.5 was associated a 1.15% (95%CI: 0.65%, 1.65%) increase in under-5 mortality. • Cause-specific mortality from diarrhea, pneumonia, digestive diseases, and preterm birth. • Supra-linear concentration-response curve with steeper slope in lower concentrations. Under-5 mortality rate is an important indicator in Millennium Development Goals and Sustainable Development Goals. To date, no nationally representative studies have examined the effects of fine particulate matter (PM 2.5) air pollution on under-5 mortality. To investigate the association of short-term exposure to PM 2.5 with under-5 mortality from total and specific causes in China. We used the national Maternal and Child Health Surveillance System to identify under-5 mortality cases during the study period of 2009 to 2019. We adopted a time-stratified case-crossover study design at the individual level to capture the effect of short-term exposure to daily PM 2.5 on under-5 mortality, using conditional logistic regression models. A total of 61,464 under-5 mortality cases were included. A 10 μg/m3 increase in concentrations of PM 2.5 on lag 0–1 d was significantly associated with a 1.15% (95%confidence interval: 0.65%, 1.65%) increase in under-5 mortality. Mortality from diarrhea, pneumonia, digestive diseases, and preterm birth were significantly associated with exposure to PM 2.5. The effect estimates were larger for neonatal mortality (<28 days), female children, and in warm seasons. We observed steeper slopes in lower ranges (<50 μg/m3) of the concentration-response curve between PM 2.5 and under-5 mortality, and positive associations remained below the 24-h PM 2.5 concentration limit recommended by WHO Air Quality Guidelines and China Air Quality Standards. This nationwide case-crossover study in China demonstrated that acute exposure to PM 2.5 may significantly increase the risk of under-5 mortality, with larger effects for neonates, female children, and during warm seasons. Relevant control strategies are needed to remove this roadblock to achieving under-5 mortality targets in developing countries. [ABSTRACT FROM AUTHOR]

[Display omitted] • The largest multi-city database with dynamic pulmonary function monitoring in adult asthmatic patients. • We found robust associations of decreased pulmonary function with PM 2.5 and PM 2.5-10. • PM 2.5-10 may be more hazardous than PM 2.5 in reducing pulmonary function. • The associations of PM 2.5 and PM 2.5-10 occurred at lag day 1 and vanished a week later. The short-term associations of fine particulate matter (PM 2.5) and coarse particulate matter (PM 2.5-10) with pulmonary function were inconsistent and rarely evaluated by dynamic measurements. Our study aimed to investigate the associations of PM 2.5 and PM 2.5–10 with real-time pulmonary function. We conducted a longitudinal study based on dynamic pulmonary function measurements among adult asthmatic patients in 25 cities of 19 provincial regions of China from 2017 to 2020. Linear mixed-effects models combined with polynomial distributed lag models were used for statistical analysis. A total of 298,396 records among 4,992 asthmatic patients were evaluated. We found generally inverse associations of PM 2.5 and PM 2.5–10 with 16 pulmonary function indicators that were independent of gaseous pollutants. The associations occurred at lag 1 d, became the strongest at lag 4 d, and vanished a week later. PM 2.5-10 had stronger associations than PM 2.5, especially in southern China. Nationally, an interquartile increase in PM 2.5-10 (28.0 μg/m3) was significantly associated with decreases in forced expiratory volume in 1 s (FEV 1, 41.6 mL), the ratio of FEV 1 in forced vital capacity (1.1%), peak expiratory flow (136.9 mL/s), and forced expiratory flow at 25–75% of forced vital capacity (54.3 mL/s). We observed stronger associations in patients of male, BMI ≥ 25 kg/m2, age ≥ 45 years old, and during warm seasons. In conclusion, this study provided robust evidence for impaired pulmonary function by short-term exposure to PM 2.5 and PM 2.5-10 in asthmatic patients using the largest dataset of dynamic monitoring. The associations can last for one week and PM 2.5-10 may be more hazardous. [ABSTRACT FROM AUTHOR]

[Display omitted] • This is the largest and multicenter study of particulate matter and ABPM. • Transient exposure to PM 2.5 elevated blood pressure within the first 12 h. • Exposure-response curves were almost linear without thresholds. • PM 2.5–10 did not show significant association with blood pressure. Epidemiological evidence from ambulatory blood pressure monitoring is needed to clarify the associations of particulate air pollution with blood pressure and potential lag patterns. We examined the associations of fine and coarse particulate matter (PM 2.5 , PM 2.5–10) with ambulatory blood pressure among 7108 non-hypertensive participants from 7 Chinese cities between April 2016 and November 2020. Hourly concentrations of PM 2.5 and PM 2.5–10 were obtained from the nearest monitoring stations. We measured four blood pressure indicators, including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and pulse pressure (PP). Linear mixed-effect models combined with distributed lag models were applied to analyze the data. Generally, very short-term exposure to PM 2.5 was significantly associated with elevated blood pressure. These effects occurred on the same hour of blood pressure measurement, attenuated gradually, and became insignificant approximately at lag 12 h. An interquartile range (IQR, 33 μg/m3) increase of PM 2.5 was significantly associated with cumulative increments of 0.58 mmHg for SBP, 0.31 mmHg for DBP, 0.38 mmHg for MAP, and 0.33 mmHg for PP over lag 0 to 12 h. The exposure–response relationship curves were almost linear without thresholds, but tended to be flat at very high concentrations. No significant associations were observed for PM 2.5–10. Our study provides independent and robust associations between transient PM 2.5 exposure and elevated blood pressure within the first 12 h, and reinforces the evidence for a linear and non-threshold exposure–response relationship, which may have implications for blood pressure management and hypertension prevention in susceptible population. [ABSTRACT FROM AUTHOR]

It remains unclear whether carbon content in airway macrophages (AM) can predict personal short-term exposure to fine particulate matter (PM 2.5) air pollution and its respiratory health effects. We aimed to evaluate the pathway from personal PM 2.5 exposure to adverse respiratory outcomes through AM carbon content. We designed a longitudinal panel study with 3 scheduled follow-ups among 113 non-smoking patients of chronic obstructive pulmonary disease in Shanghai, China, from April 2017 to January 2019. We quantified AM carbon content from induced sputum by image analysis, tested lung function and measured sputum levels of 4 pro-inflammatory cytokines and 2 anti-inflammatory cytokines. We applied the "meet in the middle" approach incorporating linear mixed-effect models to evaluate the associations from external PM 2.5 exposure to respiratory outcomes through AM carbon content. Our results indicated that personal exposure to PM 2.5 within 24 h was significantly associated with decreased forced expiratory volume in 1s and anti-inflammatory cytokines, as well as increased macrophages and pro-inflammatory cytokines. These changes were accompanied by increased areas of AM carbon and higher percentage of AM area occupied by carbon, both of which were associated with increased levels of pro-inflammatory cytokines and decreased levels of anti-inflammatory cytokines. Exposure to ambient black carbon and organic carbon in PM 2.5 within 2 days was significantly associated with increased AM carbon area and percentage of AM area occupied by carbon. Our findings reinforced the causality in respiratory health effects of PM 2.5 in which increased AM carbon content might serve as a valid exposure biomarker. • Acute PM 2.5 exposure increases AM carbon content and leads to respiratory effects. • The percentage of carbon area in AM may be a better exposure biomarker of PM 2.5. • This study reinforces the causality for the acute respiratory effects of PM 2.5. [ABSTRACT FROM AUTHOR]

• Limited evidence on the PM 2.5 constituents - infant mortality association in developing countries. • A multi-country cross-sectional study based on the Demographic and Health Surveys in Africa. • PM 2.5 was associated with increased infant mortality across 15 countries in Africa. • PM 2.5 carbonaceous fractions and sulfate play a major important role in infant mortality. Few studies have investigated the association between exposure to fine particulate matter (PM 2.5) and infant mortality in developing countries, especially for the health effects of specific PM 2.5 constituents. We aimed to examine the association of long-term exposure to specific PM 2.5 constituents with infant mortality in 15 African countries from 2005 to 2015. Based on the Demographic and Health Surveys (DHS) dataset, we included birth history records from 15 countries in Africa and conducted a multicountry cross-sectional study to examine the associations between specific PM 2.5 constituents and infant mortality. We estimated annual residential exposure using satellite-derived PM 2.5 for mass and a chemical transport model (GEOS-Chem) for its six constituents, including organic matter (OM), black carbon (BC), sulfate (SO 4 2−), nitrate (NO 3 −), ammonium (NH 4 +), and soil dust (DUST). Multivariable logistic regression analysis was employed by fitting single-constituent models, the constituent-PM 2.5 models, and the constituent-residual models. We also conducted stratified analyses by potential effect modifiers and examined the specific associations for each country. We found positive and significant associations between PM 2.5 total mass and most of its constituents with infant mortality. In the single-constituent model, for an IQR increase in pollutant concentrations, the odds ratio (OR) of infant mortality was 1.03 (95 %CI; 1.01, 1.06) for PM 2.5 total mass, and was 1.04 (95 %CI: 1.02, 1.06), 1.04 (95 %CI: 1.02, 1.05), 1.02 (95 %CI: 1.00, 1.03), 1.04 (1.01, 1.06) for BC, OM, SO 4 2−, and DUST, respectively. The associations of BC, OM, and SO 4 2− remained significant in the other two models. We observed larger estimates in subgroups with older maternal age, living in urban areas, using unclean cooking energy, and with access to piped water. The associations varied among countries, and by different constituents. The carbonaceous fractions and sulfate play a major important role among PM 2.5 constituents on infant mortality. Our findings have certain policy implications for implementing effective measures for targeted reduction in specific sources (fossil fuel combustion and biomass burning) of PM 2.5 constituents against the risk of infant mortality. [ABSTRACT FROM AUTHOR]

Predicting long-term spatiotemporal characteristics of fine particulate matter (PM 2.5) is important in China to understand historical levels of PM 2.5 , to support health effects research of both long-term and short-term exposures to PM 2.5 , and to evaluate the efficacy of air pollution control policies. Satellite-retrieved aerosol optical depth (AOD) provides a unique opportunity to characterize the long-term trends of ground-level PM 2.5 at high spatial resolution. However, the missing rate of AOD in Northeastern China (NEC) is very high, especially in winter, and challenges the accuracy of long-term predictions of PM 2.5 if left unresolved. Using random forest algorithms, this study developed a gap-filling approach combing satellite AOD, meteorological data, land use parameters, population and visibility in the NEC during 2005–2016. The model, including all predictors, combined with a model without AOD was able to fill the gap of PM 2.5 predictions caused by missing AOD at 1-km resolution. The R2 (RMSE) of the full-coverage predictions was 0.81 (18.5 μg/m3) at the daily level. Gap-filled PM 2.5 predictions on days with missing AOD reduced the relative prediction error from 28% to 2.5% in winter. The leave-one-year-out-cross-validation R2 (RMSE) of the full-coverage predictions was 0.65 (16.3 μg/m3) at the monthly level, indicating relatively high accuracy of predicted historical PM 2.5 concentrations. Our results suggested that AOD helped increase the reliability of historical PM 2.5 prediction when ground PM 2.5 measurements were unavailable, even though predictions from the AOD model only accounted for approximate 37% of the whole dataset. Predicted PM 2.5 level in NEC have increased since 2005, reached its peak during 2013–2015, then saw a major decline in 2016. Our high-resolution predictions also showed a south to north gradient and many pollution hot spots in the city clusters surrounding provincial capitals, as well as within large cities. Overall, by combining predictions from the AOD model with higher accuracy and predictions from the non-AOD model to achieve full coverage, our modeling approach could produce long-term, full-coverage historical PM 2.5 levels in high-latitude areas in China, despite the widespread and persistent AOD missingness. Unlabelled Image • AOD increased the accuracy of models for predicting historical PM 2.5 levels. • Predictions of PM 2.5 from gap-filling models achieved 100% coverage in NEC. • Full-coverage estimates corrected the prediction bias of PM 2.5 in winter of NEC. [ABSTRACT FROM AUTHOR]

• We established AQHIs for various subgroups using data from 272 Chinese cities. • Various AQHIs showed very similar magnitude for the associations with mortality. • The associations of AQHI with mortality were one-half to -fold stronger than AQI. • The curves for AQHI and mortality were consistently increasing but not for AQI. A new Air Quality Health Index (AQHI) was developed in Canada or several single cities as a promising health risk communication tool. To construct a national AQHI in China and compare its validity in predicting daily mortality risk with the existing Air Quality Index (AQI). We established the AQHI as the sum of excess total mortality risks associated with multiple air pollutants in 272 representative Chinese cities from 2013 to 2015 (termed as "total AQHI"). The mortality risks per unit change of air pollutant concentrations were determined according to a time-series analysis in each city. Separate AQHIs were established for subgroups classified by age and sex and for main cardiopulmonary diseases (termed as "specific AQHIs"). For validation, AQHIs and AQI were established using the data of 2015 (N = 272) and compared their associations with daily mortality using the data of 2013–2014 (N = 144). The concentration-response coefficients of fine particulate matter, nitrogen dioxide and ozone were adopted in constructing AQHI. There were almost linear exposure-response relationships between AQHIs and daily mortality. The total AQHI and specific AQHIs had very similar associations with daily mortality. AQHI and AQI showed similar associations with daily cause-specific mortality in terms of average magnitude, numbers of cities of positive associations and model fit statistics. AQHI may have comparable performance with AQI in communicating acute health risks of air pollution in China. There seems no need to establish specific AQHIs for different age groups, gender and causes of deaths. [ABSTRACT FROM AUTHOR]

Understanding spatial variation of air pollution is critical for public health assessments. Land Use Regression (LUR) models have been used increasingly for modeling small-scale spatial variation in air pollution concentrations. However, they have limited application in China due to the lack of spatially resolved data. Based on purpose-designed monitoring networks, this study developed LUR models to predict fine particulate matter (PM 2.5), black carbon (BC) and nitrogen dioxide (NO 2) exposure and to identify their potential outdoor-origin sources within an urban/rural region, using Taizhou, China as a case study. Two one-week integrated samples were collected at 30 PM 2.5 (BC) sites and 45 NO 2 sites in each two distinct seasons. Samples of 1/3 of the sites were collected simultaneously. Annual adjusted average was calculated and regressed against pre-selected GIS-derived predictor variables in a multivariate regression model. LUR explained 65% of the spatial variability in PM 2.5 , 78% in BC and 73% in NO 2. Mean (±Standard Deviation) of predicted PM 2.5 , BC and NO 2 exposure levels were 48.3 (±6.3) μg/m3, 7.5 (±1.4) μg/m3 and 27.3 (±8.2) μg/m3, respectively. Weak spatial corrections (Pearson r = 0.05–0.25) among three pollutants were observed, indicating the presence of different sources. Regression results showed that PM 2.5 , BC and NO 2 levels were positively associated with traffic variables. The former two also increased with farm land use; and higher NO 2 levels were associated with larger industrial land use. The three pollutants were correlated with sources at a scale of ≤5 km and even smaller scales (100–700m) were found for BC and NO 2. We concluded that based on a purpose-designed monitoring network, LUR model can be applied to predict PM 2.5 , NO 2 and BC concentrations in urban/rural settings of China. Our findings highlighted important contributors to within-city heterogeneity in outdoor-generated exposure, and indicated traffic, industry and agriculture may significantly contribute to PM 2.5 , NO 2 and BC concentrations. Image 1 • Lack of spatially resolved air pollution data limits LUR model application in China. • We are one of the few building LUR models upon specific-monitoring network in China. • PM 2.5 , BC and NO 2 models explain a large fraction of concentration variability. • We add experience on air pollution exposure assessment for population-based studies. [ABSTRACT FROM AUTHOR]

Few studies have investigated respiratory effects of particulate matter air pollution using a full range of particle size distribution. To explore the short-term associations between size-fractionated particle number concentration (PNC) and chronic obstructive pulmonary disease (COPD) mortality. We conducted a time-series study to explore the associations between size-fractionated PNC and daily COPD mortality in the Pudong New Area of Shanghai, China, from 2014 to 2016. We evaluated particle size distribution from 0.01 μm to 10 μm, which was segregated into 7 ranges to better explore the size-dependent associations. We used over-dispersed generalized additive models to estimate the associations after controlling for time trends, temperature, humidity, day of the week and holidays. A total of 5430 deaths due to COPD were identified during the study period. For size ranges from 2.5 – 10 μm, 1–2.5 μm to 0.3–1 μm, there were stronger associations between PNC and COPD mortality, but the associations were statistically insignificant. However, for the smaller size ranges from 0.3 to 0.01 μm, the associations became statistically significant and the magnitude of association remained stable. An interquartile range increase in PNC at lag 0–1 day for size ranges 0.01–0.03 μm, 0.03–0.05 μm, 0.05–0.1 μm and 0.1–0.3 μm was associated with increments of 4.44% (95% CI: 1.16%, 7.73%), 4.31% (95% CI: 1.16%, 7.47%), 4.22% (95% CI: 1.05%, 7.40%), and 4.28% (95% CI: 0.48%, 8.09%) in COPD mortality, respectively. This study suggested that particles below 0.3 μm in diameter might be mainly responsible for the adverse effect of particulate air pollution on CDPD mortality in Shanghai, China. • A study linking a full range of particle size distribution and COPD mortality. • The associations generally increased with smaller particle size. • Particles below 0.3 μm in diameter may be mainly responsible for the associations. • Particles above 0.3 μm in diameter showed no significant associations. [ABSTRACT FROM AUTHOR]