Interactions between Air Temperature and Atmospheric Particulate Matter on Mortality of People in Harbin, Heilongjiang Province, China

Objective To assess the interactions between the daily mean air temperature, inhalable particulate matter (PM₁₀), and fine particulate matter (PM_2.5) on mortality of people in Harbin, Heilongjiang province, China.

Methods The daily mortality data, meteorological data, and atmospheric pollutants concentration data, including PM₁₀, PM_2.5, etc. in Harbin from 2014 to 2016 were collected. The distributed lag nonlinear model (DLNM) with quasi-Poisson link, bivariate response surface model, and stratified model were used to detect and measure the potential interactions between atmospheric particulate matter (PM₁₀ and PM_2.5) and air temperature on the daily mortality in Harbin.

Results The bivariate response surface model showed that there were significant interactions between PM₁₀, PM_2.5 and air temperature on mortality (P < 0.05). The stratified analysis showed that at high temperature, the longer the accumulative lag days, the greater the influence of PM₁₀ and PM_2.5 on the total daily mortality. When the accumulative lag was 12 d, the accumulative risks of the total daily mortality were increased to 10.4% (95% CI: 2.7%-18.8%) and 18.2% (95% CI: 1.8%-37.1%), respectively, with the increase of PM₁₀ and PM_2.5 by 10 μg/m³ . At low and moderate temperatures, no significant correlations between PM₁₀/PM_2.5 and total mortality were found. Compared with the moderate temperature layer, PM₁₀ and PM_2.5 had significantly greater influence on the mortality at high temperature (P < 0.05). A subgroup analysis showed that at high temperature, atmospheric particulate matter had a greater influence on the mortality of males and people over 65 years of age.

Conclusion There are interactions between PM₁₀, PM_2.5 and air temperature on mortality of people in Harbin. At high temperature, PM₁₀ and PM_2.5 have greater influence on the risk of mortality.