Associations between coarse particulate matter air pollution and cause-specific mortality: A nationwide analysis in 272 Chinese cities

Abstract

BACKGROUND: Coarse particulate matter with aerodynamic diameter between 2.5 and 10 lm (PM2:5-10) air pollution is a severe environmental problem in developing countries, but its challenges to public health were rarely evaluated. OBJECTIVE: We aimed to investigate the associations between day-to-day changes in PM2:5-10 and cause-specific mortality in China. METHODS: We conducted a nationwide daily time-series analysis in 272 main Chinese cities from 2013 to 2015. The associations between PM2:5-10 concentrations and mortality were analyzed in each city using overdispersed generalized additive models. Two-stage Bayesian hierarchical models were used to estimate national and regional average associations, and random-effect models were used to pool city-specific concentration-response curves. Two-pollutant models were adjusted for fine particles with aerodynamic diameter =2:5 lm (PM2:5) or gaseous pollutants. RESULTS: Overall, we observed positive and approximately linear concentration-response associations between PM2:5-10 and daily mortality. A 10-lg=m3 increase in PM2:5-10 was associated with higher mortality due to nonaccidental causes [0.23%; 95% posterior interval (PI): 0.13, 0.33], cardiovascular diseases (CVDs; 0.25%; 95% PI: 0.13, 0.37), coronary heart disease (CHD; 0.21%; 95% PI: 0.05, 0.36), stroke (0.21%; 95% PI: 0.08, 0.35), respiratory diseases (0.26%; 95% PI: 0.07, 0.46), and chronic obstructive pulmonary disease (COPD; 0.34%; 95% PI: 0.12, 0.57). Associations were stronger for cities in southern vs. northern China, with significant differences for total and cardiovascular mortality. Associations with PM2:5-10 were of similar magnitude to those for PM2:5 in both single- and two-pollutant models with mutual adjustment. Associations were robust to adjustment for gaseous pollutants other than nitrogen dioxide and sulfur dioxide. Meta-regression indicated that a larger positive correlation between PM2:5-10 and PM2:5 predicted stronger city-specific associations between PM2:5-10 and total mortality. CONCLUSIONS: This analysis showed significant associations between short-term PM2:5-10 exposure and daily nonaccidental and cardiopulmonary mortality based on data from 272 cities located throughout China. Associations appeared to be independent of exposure to PM2:5, carbon monoxide, and ozone.