Acute Effects Of Fine Particulate Matter,nitrogen Dioxide And Ozone On Mortality And Their Interactions In The 96 Districts/counties Of China

Objective:This study aims to explore the acute effects of fine particulate matter(PM2.5),nitrogen dioxide(NO2)and ozone(O3)on mortality and their interactions,and to provide scientific basis for the formulation of air pollution prevention and control strategies.Methods:We collected daily data on mortality,air pollution and meteorological conditions from 96 Chinese districts/counties from 2015 to 2018.District/county-specific effects of PM2.5,NO2 and O3 were estimated using the generalized additive model with quasi-Poisson distribution after adjusting for time trends,temperature,relative humidity and day of week.Then,we applied a meta-analysis to pool the district/county-specific estimates,and obtained national and regional estimates of PM2.5,NO2 and O3.We also plotted the exposure-response curves.Meanwhile,several stratification analyses by season,sex and age were conducted to assess their potential effect.modification.In addition,we used two approaches to evaluate the interactions of PM2.5,NO2 and O3 on mortality.A stratification model and a joint effect model were conducted to estimate the effect modification and additive interaction,respectively.All analyses were conducted using R version 4.0.2,and size of the test was 0.05.Results:1.At the national-average level,each 10?g/m3 increase in PM2.5(lag02)was associated with a 0.35%(95%CI:0.24%,0.47%)?0.38%(95%CI:0.25%,0.50%)and 0.36%(95%CI:0.09%,0.63%)increase in total nonaccidental mortality,cardiovascular mortality and respiratory mortality,respectively;Each 10?g/m3 increase in NO2(lag02)was associated with a 0.89%(95%CI:0.66%,1.12%)?0.88%(95%CI:0.55%,1.21%)and 0.75%(95%CI:0.14%,1.37%)increase in total nonaccidental mortality,cardiovascular mortality and respiratory mortality,Vespectively;Each 10?g/m3 increase in O3(lag02)was associated with a 0.59%(95%CI:0.46%,0.72%)?0.62%(95%CI:0.44%,0.80%)and 0.76%(95%CI:0.49%,1.02%)increase in total nonaccidental mortality,cardiovascular mortality and respiratory mortality,respectively.Meanwhile,the exposure-response curves of PM2.5 and NO2 were roughly linear,consistent with the absence of a threshold.The exposure-response curves of O3 were linear at concentrations above 50?g/m3.2.There were significant differences in acute effects of PM2.5,NO2 and O3 on mortality according to region.The effects of PM2.5 and NO2 on mortality in the south are significantly stronger than those in the north,while the effects of O3 in the north are stronger than those in the south.The acute effects of NO2 and O3 on mortality had seasonal patterns.There were stronger associations between NO2 and mortality in the cold period while the associations between O3 and mortality were stronger in the warm period.In addition,the associations between air pollutants(PM2.5,NO2,O3)and mortality were higher in older people than in younger people,but only the differences by age of O3 effects were statistically significant.The acute effects of PM2.5 and NO2 on total nonaccidental mortality and respiratory mortality were stronger in females,but the acute effects of PM2.5 and NO2 on cardiovascular mortality were stronger in males,and the differences were no statistically significant.3.We found the additive interaction of PM2.5,NO2 and O3 on total nonaccidental mortality.At the national level,there was synergistic effect between PM2.5 and NO2 on mortality,the corresponding relative excess risk due to intevaction(RERI)was 0.015(95%CI:0.005,0.024).In warm period,we also found synergistic effect between O3 and NO2 on mortality,the RERI was 0.014(95%CI:0.001,0.027).In the north,there was antagonistic effect between PM2.5 and NO2 on mortality,the corresponding RERI was-0.013(95%CI:-0.026,-0.001).Conclusion:The PM2.5,NO2 and O3 were associated with the increases of total nonaccidental mortality,cardiovascular mortality and respiratory mortality.There are differences in the effects according to region,season and population.Additionally,our results suggested interactions of PM2.5,NO2 and O3 on total nonaccidental mortality.Targeted multi-pollutant prevention and control measures should be taken to reduce the impact of air pollution on human health.