Short-term effects of different PM2.5 ranges on daily all-cause mortality in Jinan, China

To examine the effects of different PM2.5 concentration ranges on daily all-cause mortality, 8768 all-cause deaths were recorded in the database of the Shandong Provincial Hospital Affiliated to Shandong First Medical University. Data of air pollutants (PM2.5 and O-3) concentration were provided by the Jinan Environment Monitoring Center. The relative risk of all-cause mortality was assessed using a quasi-Poisson regression model after adjusting for confounding factors. The concentrations of PM2.5 were divided into four ranges 0-35 mu g/m(3); 35-75 mu g/m(3); 75-115 mu g/m(3); 115-150 mu g/m(3). There was no significant relationship between PM2.5 exposure and all-cause deaths in individuals aged < 60 years. However, for individuals aged >= 60 years, there was a significant positive association between exposure concentrations and all-cause deaths within the ranges 0-35 mu g/m(3), 35-75 mu g/m(3), and 115-150 mu g/m(3) with a mortality increase of 1.07 (1.01, 1.13), 1.03 (1.00, 1.05), and 1.05 (1.01, 1.08), respectively. When the population aged >= 60 years was stratified into gender groups, exposure to PM2.5 in the range 0-35 mu g/m(3) increased the mortality risk in men but not women. All-cause mortality in women, but not men, increased significantly with exposure to PM2.5 in the ranges of 35-75, 75-115, and 115-150 mu g/m(3).