PolEASIA

Air pollution in East Asia and especially in China is an outstanding issue. The rapid economic development and urbanization during the last decades resulted in rising pollutant emissions leading to the largest pollutant concentrations in the world, largely exceeding the recommended outdoor air pollutant thresholds from the World Health Organization (WHO) for the major pollutants (ozone, PM2.5, and PM10). This pollution causes severe health problems increasing cardiovascular and respiratory diseases and premature mortality, and reduces population welfare (e.g. closure of transportation infrastructure due to lack of visibility). Robust monitoring and forecasting systems associated with downstream services providing comprehensive risk indicators are highly needed for public authorities to establish efficient pollution mitigation strategies and for populations to take preventive actions to preserve their health and welfare. In addition, a precise evaluation of the present and future impacts of Chinese pollutant emissions is of importance to quantify: first, the consequences of pollutants export on atmospheric composition and air quality all over the globe; second, the additional radiative forcing induced by the emitted and produced short-lived climate forcers (ozone and aerosols); third, the long-term health consequences of pollution exposure. To achieve this, a detailed understanding of sources of East Asian pollution is necessary. Building on a ambitious synergistic approach combining observations and modeling to bridge the scales from local to global, the PolEASIA project aims at a better documentation and quantification of the sources and the distribution of the major pollutants (such as ozone and aerosols), and of their past, present and future evolution. Inverse modeling coupling satellite observations and regional modeling will be applied to derive highly resolved (monthly, ¼ of degree) optimized inventories of NOx and NMHC (non methane hydrocarbons) emissions over China for a decade. A multi-scale approach coupling innovative satellite observations, in situ measurements and chemical transport model simulations will be developed to characterize the spatial distribution, the interannual to daily variability and the long-term trends of the major pollutants (ozone and aerosols) over East Asia. Specific studies will be conducted to quantify the role of the different processes (emissions, transport, chemical transformation) explaining the observed pollutant distributions. A particular attention will be paid to assess the natural and anthropogenic contributions to Eastern Asian pollution. The major impacts of Chinese pollution will be assessed. The consequences of the long-range transport of pollutants on regional and global atmospheric composition will be determined using both satellite observations and model simulations. Health Impact Assessment (HIA) methods coupled with model simulations will be used to estimate the long-term impacts of exposure to pollutants (PM2.5 and ozone) on cardiovascular and respiratory mortality. In addition, the radiative forcing of short-lived species (such as ozone and aerosols) will be derived from present-day simulations and simulations under future emission scenarios. Progress made with the understanding of pollutant sources, especially in terms of modeling of pollution over East Asia and advanced numerical approaches such as inverse modeling will serve the development of an efficient and marketable forecasting system for regional outdoor air pollution. Additional modules will be coupled with the forecasting system including end-user friendly applications to provide comprehensive indices for health and visibility risks to public authorities and populations. The performances of this upgraded forecasting system will be evaluated and promoted to ensure a good visibility of the French technology.