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Objective: To investigate personal exposures to nitrogen oxides (NO X ) and nitrogen di-oxide (NO 2 ) and the influence of baseline personal characteristics, living environment and daily activity patterns of the participants on the exposures among adults over 35 in Tianjin and Shanghai., Methods: In this panel study, 91 healthy nonsmoking adults aged over 35 from Tianjin and Shanghai participated in our study. The study was conducted in summer and winter. The participants were followed for three times with an interval of at least two weeks. Only participants in Shanghai were followed once in winter because of the COVID-19 pandemic. Twenty-seven participants completed follow-up visits in both seasons. We measured their 24 h personal exposures to NO X and NO 2 and collected their baseline and time-activity information through questionnaire/diary. The linear mixed model was used to analyze the associations between potential influencing factors and personal NO X and NO 2 exposure levels., Results: There were 349 follow-up visits with valid 24 h personal NO 2 and NO X exposure measurements in the two cities. The ave-rage 24 h personal exposures to NO 2 and NO X (volume fraction) in Tianjin participants were 18.0×10 -9 and 26.2×10 -9 in summer, and 31.0×10 -9 and 54.9×10 -9 in winter, respectively; and the average 24 h personal exposures to NO 2 and NO X in Shanghai participants were 38.7×10 -9 and 100.0×10 -9 in summer, and 45.5×10 -9 and 139.2×10 -9 in winter, respectively. The results of univariate regression analysis showed that their personal NO X exposure levels were significantly associated with city, season, gender, average daily cooking times, and ambient NO 2 concentrations measured at fixed-site monitoring stations. In addition to the above factors, the personal NO X exposure levels were also significantly associated with educational level and the personal NO 2 exposure levels were also significantly associated with passive smoking, average daily home time, cooking energy type, residential distance from main traffic road, and use of kitchen ventilators. Multivariate regression analysis showed that the personal exposure levels of NO 2 and NO X were significantly lower in Tianjin than that in Shanghai, were significantly lower in summer than that in winter, and were significantly and positively associated with ambient NO 2 concentrations measured at fixed-site monitoring stations. In addition, personal NO X exposure levels were significantly lower in females than in males, and personal NO 2 exposure levels were significantly positively associated with average daily cooking times and significantly inversely associated with average daily home time. For every interquartile range ( IQR ) increase (12.7×10 -9 ) in ambient NO 2 , the personal NO 2 exposure levels increased by 27.5% (95% CI : 17.0%-38.9%), and personal NO X exposure levels increased by 16.1% (95% CI : 7.1%-25.8%)., Conclusion: Season, city and ambient NO 2 concentrations are significant influencing factors of personal exposure levels of NO 2 and NO X. At the same time, the personal exposures levels of NO 2 are also affected by lifestyle factors. Our study provides scientific evidence for making precise air pollution control decisions and reducing the exposure levels of NO X in the population.

Particulate matter with diameters ≤2.5 μm (PM 2.5 ) has been identified as a significant air pollutant contributing to premature mortality. Nevertheless, the specific compositions within PM 2.5 that play the most crucial role remain unclear, especially in areas with high pollution concentrations. This study aims to investigate the individual and joint mortality risks associated with PM 2.5 inorganic chemical compositions and identify primary contributors. In 1998, we conducted a prospective cohort study in four northern Chinese cities (Tianjin, Shenyang, Taiyuan, and Rizhao). Satellite-based machine learning models calculated PM 2.5 inorganic chemical compositions, including sulfate (SO 4 2- ), nitrate (NO 3 - ), ammonium (NH 4 + ), and chloride (Cl - ). A time-varying Cox proportional hazards model was applied to analyze associations between these compositions and cardiorespiratory mortality, encompassing nonaccidental causes, cardiovascular diseases (CVDs), nonmalignant respiratory diseases (RDs), and lung cancer. The quantile-based g-computation model evaluated joint exposure effects and relative contributions of the compositions. Stratified analysis was used to identify vulnerable subpopulations. During 785,807 person-years of follow-up, 5812 (15.5%) deaths occurred from nonaccidental causes, including 2932 (7.8%) from all CVDs, 479 (1.3%) from nonmalignant RDs, and 552 (1.4%) from lung cancer. Every interquartile range (IQR) increase in SO 4 2- was associated with mortality from nonaccidental causes (hazard ratio: 1.860; 95% confidence interval: 1.809, 1.911), CVDs (1.909; 1.836, 1.985), nonmalignant RDs (2.178; 1.975, 2.403), and lung cancer (1.773; 1.624, 1.937). In the joint exposure model, a simultaneous rise of one IQR in all four compositions increased the risk of cardiorespiratory mortality by at least 36.3%, with long-term exposure to SO 4 2- contributing the most to nonaccidental and cardiopulmonary deaths. Individuals with higher incomes and lower education levels were found to be more vulnerable. Long-term exposure to higher levels of PM 2.5 inorganic compositions was associated with significantly increased cardiopulmonary mortality, with SO 4 2- potentially being the primary contributor. These findings offer insights into how PM 2.5 sources impact health, aiding the development of more effective governance measures., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Co-published by Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, and American Chemical Society.)

Previous studies have shown that exposure to black carbon (BC, a tracer of traffic-related air pollution) and psychosocial stress are both associated with adverse cardiac effects, but whether psychosocial stress could modify the cardiac effects of BC is unclear. To investigate the potential modifying effect of psychosocial stress on the associations between acute exposure to BC and typical cardiac health variables, real-time personal 24 h measurements were conducted in a repeated-measure study among adults with elevated blood pressure (high-risk group) and a panel study among normal adults (low-risk group) in China. Measured cardiac health variables included ST-segment depression events, heart rate, and heart rate variability (HRV) variables. Perceived Stress Scale, State Anxiety Inventory and Self-rating Depression Scale were used to assess the recent psychosocial stress status of the participants, and a composite stress index was established based on these scales. Generalized linear mixed-effects model was used to analyze the associations between BC exposure and cardiac health variables and potential effect modification by psychosocial stress. A total of 97 24 h measurements among 97 participants in the repeated-measure study and 202 24 h measurements among 87 participants in the panel study were included in the final analysis. Acute BC exposure was significantly associated with increased ST-segment depression events and heart rate and decreases in HRV in both studies. The marginal effects of acute BC exposure on most cardiac health variables generally tended to be amplified under higher vs low levels of psychosocial stress in both studies, with the composite stress index apparently modifying the associations of BC exposure with most ST-segment depression events and HRV variables. These findings suggest that psychosocial stress may increase the participants' cardiac susceptibility to BC exposure, which could be helpful for the identification of susceptible individuals in the context of traffic-related air pollution., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Co-published by Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, and American Chemical Society.)

Several literatures have examined the risk of chronic respiratory diseases in association with short-term ambient PM 2.5 exposure in China. However, little evidence has examined the chronic impacts of PM 2.5 exposure on morbidity of chronic respiratory diseases in cohorts from high pollution countries. Our study aims to investigate the associations. Based on a retrospective cohort among adults in northern China, a Cox regression model with time-varying PM 2.5 exposure and a concentration-response (C-R) curve model were performed to access the relationships between incidence of chronic respiratory diseases and long-term PM 2.5 exposure during a mean follow-up time of 9.8 years. Individual annual average PM 2.5 estimates were obtained from a satellite-based model with high resolution. The incident date of a chronic respiratory disease was identified according to self-reported physician diagnosis time and/or intake of medication for treatment. Among 38,047 urban subjects analyzed in all-cause chronic respiratory disease cohort, 482 developed new cases. In CB (38,369), asthma (38,783), and COPD (38,921) cohorts, the onsets were 276, 89, and 14, respectively. After multivariable adjustment, hazard ratio and 95% confidence interval for morbidity of all-cause chronic respiratory disease, CB, asthma, and COPD were 1.15 (1.01, 1.31), 1.20 (1.00, 1.42), 0.76 (0.55, 1.04), and 0.66 (0.29, 1.47) with each 10 μg/m 3 increment in PM 2.5 , respectively. Stronger effect estimates were suggested in alcohol drinkers across stratified analyses. Additionally, the shape of C-R curve showed an increasing linear relationship before 75.00 μg/m 3 concentrations of PM 2.5 for new-onset all-cause chronic respiratory disease, and leveled off at higher levels. These findings indicated that long-term exposure to high-level PM 2.5 increased the risks of incident chronic respiratory diseases in China. Further evidence of C-R curves is warranted to clarify the associations of adverse chronic respiratory outcomes involving air pollution., 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 Inc. All rights reserved.)

Evidence is still limited for the role of long-term PM 2.5 exposure in cerebrovascular diseases among residents in high pollution regions. The study is aimed to investigate the long-term effects of PM 2.5 exposure on stroke mortality, and further explore the effect modification of temperature variation on the PM 2.5 -mortality association in northern China. Based on a cohort data with an average follow-up of 9.8 years among 38,435 urban adults, high-resolution estimates of PM 2.5 derived from a satellite-based model were assigned to each participant. A Cox regression model with time-varying exposures and strata of geographic regions was employed to assess the risks of stroke mortality associated with PM 2.5 , after adjusting for individual risk factors. The cross-product term of PM 2.5 exposure and annual temperature range was further added into the regression model to test whether the long-term temperature variation would modify the association of PM 2.5 with stroke mortality. Among the study participants, the annual mean level of PM 2.5 concentration was 66.3 μg/m 3 ranging from 39.0 μg/m 3 to 100.6 μg/m 3 . For each 10 μg/m 3 increment in PM 2.5 , the hazard ratio (HR) was 1.31 (95% CI: 1.04-1.65) for stroke mortality after multivariable adjustment. In addition, the HRs of PM 2.5 decreased gradually as the increase of annual temperature range with the HRs of 1.95 (95% CI: 1.36-2.81), 1.53 (95% CI: 1.06-2.22), and 1.11 (95% CI: 0.75-1.63) in the low, middle, and high group of annual temperature range, respectively. The findings provided further evidence of long-term PM 2.5 exposure on stroke mortality in high-exposure settings such as northern China, and also highlighted the view that assessing the adverse health effects of air pollution might not ignore the role of temperature variations in the context of climate change., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)