Dynamic Assessment Of The Air Pollution-Related Disease Burdens And Its Response To Reductions In China

Long-term exposure to high concentrations of air pollution poses a serious threat to public health in China.Based on this,the State Council implemented the Air Pollution Prevention and Control Action Plan?the Action Plan?in 2013,which aims to significantly reduce PM_2.5 concentrations in key areas of China.However,the health benefits associated with the Action Plan have not been well explained.Also,although PM_2.5 pollution has been significantly improved in China,the problem of air pollution(PM_2.5 and O₃)is still prominent.To further reduce pollutant concentrations and their health risks is one of the urgent problems in China.To solve this problem,it is necessary to evaluate the specific differences in disease burdens,recognize its source contribution,and explore its response to air quality improvement.First,this study simulated the concentration of air pollutants in China from 2008 to2016 using the WRF-Chem model and emission inventory and analyzed the spatiotemporal characteristics of PM_2.5 and O₃.Second,the exposure-response relationship function and the value of a statistical life method were combined to quantify the specific differences in disease burdens of different populations,diseases,and regions.At the same time,the decomposition method was used to evaluate the contribution of driving factors such as pollutant concentrations,baseline mortality,population,age structure,and per capita gross domestic product to disease burdens,to explain the changing trend before and after the implementation of the Action Plan.Third,a set of sensitivity tests were designed using the WRF-Chem model to quantitatively assess the spatiotemporal changes in the contribution of emission sources such as industrial,power,residential,transport,agriculture,natural,and biomass burning to air pollutants(PM_2.5 and O₃)and their disease burdens in China.Finally,the predicted values of population and baseline mortality in 2030 were combined to explore the future trend of disease burdens under different air pollution control scenarios.The research conclusions of this paper are as follows:?1?The concentrations of PM_2.5 and O₃ in China showed obvious spatiotemporal characteristics during the study period.The high-value areas of PM_2.5 were mainly distributed in the Beijing-Tianjin-Hebei and surrounding areas?BTHS?,the Yangtze River Delta?YRD?,the Fenhe and Weihe Plain?FWP?,the Sichuan Basin?SCB?,the Triangle of Central China?TCC?,and the desert areas in the northwest.Except for the desert areas,the annual PM_2.5 concentrations in the above key areas decreased by more than 20?g/m³.Areas with high O₃ were mainly distributed in the Qinghai-Tibet Plateau,Southwest,Central,North,and South China.The annual average daily maximum 8-h O₃ concentrations?ADMA8?in the eastern region showed an overall upward trend with the increase in some locales such as BTHS,YRD,and the Pearl River Delta?PRD?reached 30?g/m³.In 2016,60.0%and 33.7%of the residents nationwide lived in areas where the annual PM_2.5 and ADMA8 exceeded the standard,respectively,which was 15%lower and 19%higher than that of 2008,respectively.?2?In 2016,PM_2.5 and O₃ pollution caused 1.25 million and 108,000 premature deaths,respectively,accounting for 13.9%of the total deaths.There were significant differences in disease burdens among different populations,diseases,and regions.Stroke and chronic obstructive pulmonary disease?COPD?accounted for 46.6%and 30.1%of PM_2.5-related deaths,respectively.Per-capita PM_2.5-related mortality of elderly people aged?75 years?1103.0 deaths per 100,000?was much higher than that of young people aged 25-44 years?10.3 deaths per 100,000?.Additionally,regions with high air pollution and/or densely populated areas such as BTHS,YRD,and PRD had a higher disease burden,while Northwest China had a lower disease burden.?3?Premature deaths caused by air pollution changed significantly before and after the implementation of the Action Plan.PM_2.5-related deaths increased by 43,000?3.6%?from2008 to 2016 due to population growth and aging,even though PM_2.5 and baseline mortality declined.However,PM_2.5-related deaths decreased by 176,000?14.9%?from 2014 to 2016after the implementation of the Action Plan.Unlike PM_2.5,the deterioration of O₃ caused by the Action Plan increased the disease burdens?19,000?.Although the reduction in baseline mortality could offset some O₃-related deaths,there was still an increase of 14,000?14.9%?over the study period.?4?There was obvious spatiotemporal heterogeneity in the contribution of different emission sources to pollutant concentrations and disease burdens.Residential sources were the most important source of PM_2.5 in winter,with a higher than 50%contribution rate in most northern regions,while in other seasons,industrial sources were the most important source of PM_2.5 with a 30%?50%contribution rate in heavily polluted.Except for industrial sources in summer,the contribution rate of anthropogenic sources to O₃ was negative in some parts of BTH and YRD,which means the O₃ concentrations increased after the emission source was closed.Industrial and residential pollution sources accounted for 35.0%and 27.8%of air pollution attributable deaths,respectively,which were the most important emission sources that cause disease burdens.The contribution of various sources to attributable deaths varied greatly in different provinces.The contribution rate of industrial sources was higher in Shanghai and Jiangsu,while that of residential sources was higher in Heilongjiang and Jilin,and that of natural sources was highest in Xinjiang.?5?More efforts would be made to reduce PM_2.5-related deaths in heavily polluted areas.To halve the PM_2.5-related deaths,PM_2.5 concentrations needed to be reduced by more than 70%in heavily polluted areas exceeding 70?g/m³,and only 20%in low concentration locales below 10?g/m³.?6?Factors such as aging in the future have brought great challenges to the prevention and control of health risks.If the annual PM_2.5 concentrations remain at the level of 2016,PM_2.5-related deaths would increase by 304,000 in 2030,driven by factors such as aging.Even if the annual PM_2.5 concentrations reach the standard?35?g/m³?in 2030,PM_2.5-related deaths would still increase by 7.5%compared with 2016.A further reduction of PM_2.5 concentrations to 10?g/m³ can significantly reduce premature mortality?-65.4%?.In summary,although the implementation of the Action Plan has brought substantial benefits to PM_2.5 and its disease burdens,it has a negative impact on O₃ and its disease burdens.Therefore,it is necessary to pay attention to the coordinated control of PM_2.5 and O₃ pollution.Besides,considering the non-linear response relationship between PM_2.5 and premature deaths,as well as future population trends,China still needs to formulate stricter standards than the“Ambient Air Quality Standards?GB 3095-2012?”.At the same time,more stringent measures needed to be taken to reduce emissions from major pollution sources such as residential and industrial sources.Only in this way can the health and wealth of residents be better protected,especially for sensitive groups such as patients with cardio-cerebrovascular diseases,particularly in the areas with high disease burdens.