Abstract 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 O3) 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 μg/m3; 35–75 μg/m3; 75–115 μg/m3; 115–150 μg/m3. There was no significant relationship between PM2.5 exposure and all-cause deaths in individuals aged