Background:Air pollutants and their pathogenic effects differ among regions and seasons.We aimed to explore the relationship between fine particulate matter (PM2.5),sulfur dioxide (SO2),and ozone-8 hours (O3-8h) concentrations in heating and non-heating seasons and the associated death risk due to cardiovascular diseases (CDs),respiratory diseases (RDs),and malignant tumors.Methods:Data were collected in Shenyang,China,from April 2013 to March 2016.We analyzed the correlation or lagged effect of atmospheric pollutant concentration,meteorological conditions,and death risk due to disorders of the circulatory system,respiratory system,and malignant tumor in heating and non-heating seasons.We also used multivariate models to analyze the association of air pollutants during holidays with the death risk due to the evaluated diseases while considering the presence or absence of meteorological factors.Results:An increase in the daily average SO2 concentration by 10 μg/m3 increased the death risk by CDs,which reached a maximum of 2.0％ (95％ confidence interval [CI]:1.3％-2.7％) on lagging day 4 during the non-heating season and 0.2％ (95％ CI:0.1％-0.4％) on lagging day 3 during the heating season.The risk of death caused by RDs peaked on lagging day 1 by 0.8％ (95％ CI:0.4％-1.2％) during the heating season.An increase in O3-8h concentration by 10 μ g/m3 increased the risk of RD-related death on lagging day 2 by 1.0％ (95％ CI:0.4％-1.7％) during the non-heating season,which was significantly higher than the 0.1％ (95％ CI:0-0.9％) increase during the heating season.Further,an increase in the daily average PM2.5 concentration by 10 μg/m3 increased the risk of death caused by RDs by 0.3 ％ and 0.8 ％ during heating and non-heating seasons,respectively,which peaked on lagging day 0.However,air pollution was not significantly associated with the risk of death caused by malignant tumors.Conclusion:Short-term exposure to PM2.5,SO2,and O3 during the non-heating season resulted in higher risks of CD-related death,followed by RD-related death.