Under-Appreciated Anthropogenic Coarse Particulate Matter in China: Quantifying the Emission and Impacts on Climate and Atmospheric Chemistry

While the majority of research has focused on fine particulate matter (PM2.5), it hasbeen observed that coarse PM (particulate matter with a diameter between 2.5 and10μm) also presents a severe environmental challenge in China. Coarse PM has beenfound to have adverse health impacts comparable to those of PM2.5, and it can influencethe formation of other pollutants by modifying atmospheric chemistry. Furthermore,coarse PM can influence the climate by changing earth’s radiation balance and cloudproperties. The Intergovernmental Panel on Climate Change’s sixth assessment report(IPCC AR6) underscores that current climate assessments may overlook a significantportion of climate effect from coarse PM.Historically, the primary focus of coarse PM research has been on natural desert dustand marine sea salt aerosol. However, recent observations suggest that anthropogenicsources, such as road dust, agricultural activities, and combustion processes, are thepredominant components of coarse PM in most regions of China. Due to the lack ofaccurate national emission inventory, current models used for air quality and climateapplications either do not consider anthropogenic coarse PM or substantiallyunderestimate its burden. It thus appears essential to estimate the emissions ofanthropogenic coarse PM and understand its role in atmospheric chemistry and theclimate system.In this project, we aim to quantify the emissions and impacts of anthropogenic coarseparticles in China. This will be achieved by developing an observational-constrainedemission inventory using a Bayesian inverse modeling framework. This emissionestimation will be incorporated into a chemical transport model and a radiative transfermodel. These models will simulate the spatio-temporal variations of anthropogeniccoarse PM, estimate its direct climate effect due to aerosol-radiation interaction, indirectclimate effect via changing cloud albedo, and explore its impacts on atmosphericchemistry and other pollutants. The findings from this study will improve currentunderstanding of coarse aerosols, enabling more precise air quality and climateassessments, and informing the development of strategies to address air pollution andclimate change. It will also provide methodology framework to study anthropogeniccoarse PM at other locations around the world. The gridded data of emission inventorycreated in this project can be used for various applications and input for other models.4/52