Mortality burden attributable to PM in Zhejiang province, China.

BACKGROUND

Limited evidence is available on the health effects of particulate matter with an aerodynamic diameter of <1 μm (PM), mainly due to the lack of its ground measurement worldwide.

OBJECTIVES

To identify and examine the mortality risks and mortality burdens associated with PM, PM, and PM in Zhejiang province, China.

METHODS

We collected daily data regarding all-cause (stratified by age and gender), cardiovascular, stroke, respiratory, and chronic obstructive pulmonary disease (COPD) mortality, and PM, PM, and PM, from 11 cities in Zhejiang province, China during 2013 and 2017. We used a quasi-Poisson regression model to estimate city-specific associations between mortality and PM concentrations. Then we used a random-effect meta-analysis to pool the provincial estimates. To show the mortality burdens of PM, PM, and PM, we calculated the mortality fractions and deaths attributable to these PMs.

RESULTS

Daily concentrations of PM, PM, and PM ranged between 0-199 μg/m, 0-218 μg/m, and 0-254 μg/m, respectively; Mortality effects were significant in lag 0-2 days. The relative risks for all-cause mortality were 1.0064 (95% CI: 1.0034, 1.0094), 1.0061 (95% CI: 1.0034, 1.0089), and 1.0060 (95% CI: 1.0038, 1.0083) associated with a 10 μg/m increase in PM, PM and PM, respectively. Age- and gender-stratified analysis shows that elderly people (aged 65+) and females are more sensitive to PMs. The mortality fractions of all-cause mortality were estimated to be 2.39% (95% CI: 1.28, 3.48) attributable to PM, 2.53% (95% CI: 1.42, 3.63) attributable to PM, and 3.08% (95% CI: 1.95, 4.19) attributable to PM. The ratios of attributable cause-specific deaths for PM/PM, PM/PM, and PM/PM were higher than the ratios of their respective concentrations.

CONCLUSIONS

PM, PM and PM are risk factors of all-cause, cardiovascular, stroke, respiratory, and COPD mortality. PM accounts for the vast majority of short-term PM- and PM-induced mortality. Our analyses support the notion that smaller size fractions of PM have a more toxic mortality impacts, which suggests to develop strategies to prevent and control PM in China, such as to foster strict regulations for automobile and industrial emissions.