ABSTRACT
Objective @#To examine the association between acute exposure to traffic-related air pollutants (TRAP) NOX and NO2 and outpatient visits of pediatric respiratory diseases. @*Methods @#Data regarding outpatient visits to Department of Respiratory Diseases of Beijing Children's Hospital from 2015 to 2020 were collected, and the concentrations of nitrogen oxides (NOX), nitrogen dioxide (NO2) and other TRAP were collected from the surveillance sites assigned by the Peking University Health Science Center. A time-stratified case-crossover design was employed, and a conditional logistic regression model was created to examine the association between NOX and NO2 acute exposure and outpatient visits of pediatric respiratory diseases. @*Results @#The daily mean outpatient visits of pediatric respiratory diseases were 571 (interquartile range, 554) person-times among children at ages of 0 to 14 years in Beijing Children's Hospital from 2015 to 2020, and the daily mean outpatient visits for upper respiratory tract infections (URI), bronchitis, and pneumonia were 265 (interquartile range, 282), 143 (interquartile range, 178) and 128 (interquartile range, 120) person-times, respectively. The daily mean concentrations of atmospheric NOX and NO2 were 67.8 (interquartile range, 50.7) and 49.3 (interquartile range, 30.7) μg/m3, respectively. Conditional logistic regression analysis showed the largest lagged effect of NOX and NO2 on pediatric respiratory diseases at cumulative lags of 0 to 7 days. An increase in NOX concentrations by an interquartile range resulted in the excess risks of URI, bronchitis and pneumonia by 6.87% (95%CI: 6.37%-7.38%), 7.25% (95%CI: 6.51%-7.99%), and 5.51% (95%CI: 4.69%-6.33%), and an increase in NO2 concentrations by an interquartile range resulted in excess risks of URI, bronchitis and pneumonia by 5.71% (95%CI: 5.12%-6.31%), 5.32% (95%CI: 4.51%-6.14%), and 4.83% (95%CI: 3.91%-5.75%), respectively. NOX and NO2 presented a more remarkable effect on outpatient visits of pediatric respiratory diseases among children at ages of over 5 years. @*Conclusion @#NOx and NO2 acute exposure may increase the outpatient visits of pediatric respiratory diseases.
ABSTRACT
Background The increasing threats of air pollution and extreme weather have been widely recognized in recent years in China, but their individual and joint effects on cardio-cerebrovascular mortality are unclear. Objective This study aims to investigate the individual effects of and potential interactions between oxidant pollutants and ambient temperature on cardio-cerebrovascular mortality risks. Methods We collected daily data on death counts of cardio-cerebrovascular diseases, concentrations of ambient air pollutants, and meteorological parameters in Guangzhou, Chinabetween 1 January 2006 and 31 December 2016. A generalized additive model with a Poisson distribution was conducted to assess the associations of oxidant pollutants and ambient temperature with cardio-cerebrovascular mortality risks. Bivariate response surface models and stratified analyses were further adopted to qualitatively and quantitatively examine the potential interactions between oxidant pollutants and ambient temperature on cardio-cerebrovascular mortality risks. Results During the study period, the daily averages were 60.3 μg·m−3 for ozone (O3), 50.9 μg·m−3 for combined atmospheric oxidant capacity (Ox), 32.5 μg·m−3 for nitrogen dioxide (NO2), and 22.3℃ for ambient temperature. The average daily death counts of coronary and stroke diseases were 20 and 15, respectively. Per 10 μg·m−3 increment in O3, Ox, and NO2 were associated with increased coronary mortality risks (excess risk, ER) of 1.26% (95%CI: 0.79%-1.74%), 1.61% (95%CI: 0.99%-2.23%), and 1.33% (95%CI: 0.59%-2.07%), and with increased stroke mortality risks of 1.56% (95%CI: 1.04%-2.09%), 2.30% (95%CI: 1.60%-3.01%), and 2.93% (95%CI: 2.07%-3.79%) over cumulative lags of 2-5 days, respectively. The exposure-response relationships between ambient temperature and coronary and stroke mortality risks exhibited an inverse "J" shape, with the minimum mortality at temperatures of 25.7℃ for coronary disease and 27.3℃ for stroke. Our results further showed potentially synergic effects of higher temperatures and higher levels of O3 and Ox exposures on coronary mortality risks, and the relative ER due to interactions was 0.103 (95%CI: 0.028-0.178) for O3 and 0.079 (95%CI: 0.004-0.154) for Ox. We didn't find evidence of an interaction between oxidant pollutants and low temperature. Conclusion Short-term exposures to oxidant pollutants are associated with increased cardio-cerebrovascular mortality risks, and the interactive effects of high temperature and oxidant pollutants are synergistic in relation to cardio-cerebrovascular mortality risks.