Background Atmospheric particulate matter pollution is a serious threat to human health, and is closely related to the death of residents.

Objective This study aims to evaluate the relationship of PM_2.5 with non-accidental deaths of residents in five representative urban districts of Chongqing.

Methods The daily death, air pollution, and meteorological data of five representative urban districts of Chongqing, including Yuzhong, Shapingba, Nan'an, Jiulongpo, and Jiangbei, from 2014 to 2018 were collected. The total number of daily non-accidental deaths and average concentrations of air pollutants in the five districts were calculated. All data were analyzed using generalized additive models while adjusting selected confounding factors including long-term trend, seasonal effect, meteorological conditions (including mean temperature and relative humidity), and day-of-the-week effect. The acute effects of singular PM_2.5 exposure and its combination with SO₂, NO₂, and CO on the non-accidental death of residents were also evaluated. All the analyses were stratified by gender to compare the differences.

Results Among the five representative urban districts of Chongqing from 2014 to 2018, there were an average of 70 non-accidental deaths per day, including 41 men and 29 women. The daily concentration of PM_2.5 was 51μg·m^-3, and there were a total of 299 days with an unqualified daily concentration of PM_2.5, accounting for 15.35%. The single-pollutant model revealed that the effect of PM_2.5 on non-accidental death was significant between lag0-3 day, and was greatest at lag1 day:a 10 μg·m^-3 increase in PM_2.5 concentration was associated with an increase in non-accidental mortality by 0.62% (95% CI:0.27%-0.97%), the association was higher in females (ER=0.85%, 95% CI:0.39%-1.31%) than in males (ER=0.49%, 95% CI:0.09%-0.89%), and the difference of ER between males and females was 0.35% (95% CI:0.13%-0.57%). The results of two-pollutant model indicated that the effect of PM_2.5 on non-accidental death was reduced to null when SO₂ or NO₂ was included, and increased to 0.69% (95% CI:0.26%-1.13%) when CO was included. In the all-pollutant model, only the effect of PM_2.5 on non-accidental death for females was significant, and a 10 μg·m^-3 increase in PM_2.5 concentration was associated with an increase in nonaccidental mortality for females by 0.77% (95% CI:0.10%-1.44%). In all multiple-pollutant models, the effects were higher in females than in males, and the interval of the differences was 0.35%-0.54%.

Conclusion The increase in PM_2.5 concentration in the five urban districts of Chongqing would lead to an increase in non-accidental death, and its acute effects are more severe in female populations.