There has been a long history of debate regarding whether ambient nitrogen dioxide (NO2) directly affects human health.
We conducted a nationwide time-series analysis in 272 major Chinese cities (2013–2015) to evaluate the associations between short-term exposure to NO2 and cause-specific mortality. We used the overdispersed generalized linear model together with the Bayesian hierarchical model to estimate the associations between NO2 and mortality at the national and regional levels. We examined two-pollutant models with adjustment of fine particles, sulfur dioxide, carbon monoxide, and ozone to evaluate robustness for the effects of NO2.
At the national-average level, we observed linear and positive associations between NO2 and mortality from all causes and main cardiorespiratory diseases. A 10 μg/m3 increase in 2-day average concentrations of NO2 would lead to increments of 0.9% (95% posterial interval [PI], 0.7%, 1.1%) in mortality from total nonaccidental causes, 0.9% (95% PI, 0.7%, 1.2%) from total cardiovascular disease, 1.4% (95% PI, 0.8%, 2.0%) from hypertension, 0.9% (95% PI, 0.6%, 1.2%) from coronary heart disease, 0.9% (95% PI, 0.5%, 1.2%) from stroke, 1.2% (95% PI, 0.9%, 1.5%) from total respiratory diseases, and 1.6% (95% PI, 1.1%, 2.0%) from chronic obstructive pulmonary disease. There were no appreciable differences in estimates from single-pollutant and two-pollutant models. The associations were stronger in the south of China, in the elderly, and in females.
The present study provided robust epidemiologic evidence of associations between day-to-day NO2 and mortality from total natural causes and main cardiorespiratory diseases that might be independent of other criteria air pollutants.
From the aSchool of Public Health, Key Lab of Public Health Safety of the Ministry of Education and Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China
bShanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Fudan University, Shanghai, China
cNational Center for Chronic Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
dDepartment of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA.
Submitted August 23, 2017; accepted March 28, 2018.
Supported by the National Natural Science Foundation of China (91643205), National Environmental Public Welfare Research Program of Ministry of Environmental Protection of China (201509062), Public Welfare Research Program of National Health and Family Planning Commission of China (201502003), and China Medical Board Collaborating Program (16–250).
The authors report no conflicts of interest.
R.C. and P.Y. contributed equally to this work.
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Correspondence: Maigeng Zhou, National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing 100050 China. E-mail: email@example.com and Haidong Kan, PhD, Department of Environmental Health, School of Public Health, Fudan University, P.O. Box 249, 130 Dong-An Road, Shanghai 200032, China. E-mail: firstname.lastname@example.org.