Characteristics of the Exposure-Response Relationship of Particulate Matter and Mortality: A Time Series Analysis of 7 Cities in China.

Abstract

To explore the characteristics of the exposure-response relationship of particulate matter concentration and mortality on the multicity scale in China. Generalized additive models were used to explore the short-term effects of particulate matter with an aerodynamic diameter of less than 10 μm (PM10) on mortality while adjusting for confounding variables, including seasonal periodicity, air temperature, relative humidity, day-of-the-week effect, and holiday effect. Additionally, possible PM10 thresholds for daily mortality were evaluated. In most cities, the relationships of PM10 concentration and daily cause-specific mortalities were all nearly linear when PM10 concentration was below 150 μg/m3. The estimated PM10 thresholds associated with nonaccidental and cardiovascular mortalities were 80 μg/m3 and 45 μg/m3, respectively. Our findings indicated that, at least in China, the PM10 pollutant has threshold effects.