Background: Limited evidence is available on the health effects of particulate matter with an aerodynamic diameter of <1 μm (PM 1 ), mainly due to the lack of its ground measurement worldwide. Objectives: To identify and examine the mortality risks and mortality burdens associated with PM 1 , PM 2.5 , and PM 10 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 1 , PM 2.5 , and PM 10 , 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 1 , PM 2.5 , and PM 10 , we calculated the mortality fractions and deaths attributable to these PMs. Results: Daily concentrations of PM 1 , PM 2.5 , and PM 10 ranged between 0–199 μg/m 3 , 0–218 μg/m 3 , and 0–254 μg/m 3 , 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 3 increase in PM 1 , PM 2.5, and PM 10 , 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 1 , 2.53% (95% CI: 1.42, 3.63) attributable to PM 2.5 , and 3.08% (95% CI: 1.95, 4.19) attributable to PM 10 . The ratios of attributable cause-specific deaths for PM 1 /PM 2.5 , PM 1 /PM 10 , and PM 2.5 /PM 10 were higher than the ratios of their respective concentrations. Conclusions: PM 1 , PM 2.5 and PM 10 are risk factors of all-cause, cardiovascular, stroke, respiratory, and COPD mortality. PM 1 accounts for the vast majority of short-term PM 2.5 - and PM 10 -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 1 in China, such as to foster strict regulations for automobile and industrial emissions.
Hu, K., Guo, Y., Hu, D., Du, R., Yang, X., Zhong, J., … Qi, J. (2018). Mortality burden attributable to PM 1 in Zhejiang province, China. Environment International, 121, 515–522. https://doi.org/10.1016/j.envint.2018.09.033