This session highlights the influence of human activity and emissions on air quality, human exposure, and the resulting health impacts. This includes studies of anthropogenic and biogenic emission sources and their transformations in urban areas, emerging energy sources and their impacts on air quality, urban scale air quality studies (including megacities), indoor air quality and modeling, exposure and health effects studies, and studies that address the interaction of urban air pollution with surrounding rural and regional areas, including tropical and sub-tropical regions.

This session highlights fundamental experimental and theoretical research that underpins our understanding of atmospheric chemistry. This includes studies of gas-phase kinetics, photochemistry, heterogeneous chemistry, spectroscopic and thermodynamic properties of gases and particles, chemical mechanism development, and process-level or mechanistic understanding of emissions and deposition processes.

This session highlights the influence of atmospheric chemistry on ecosystems and interactions between atmospheric chemistry and biogeochemical cycles, including carbon, nitrogen, and others. This incorporates studies on surface-atmosphere exchange including biomass burning and dust, and transformations in the background atmosphere such as the remote marine boundary layer, as well as land-use activities such as deforestation, agriculture and food production. The session will also address the influence of these activities on air quality and the role of atmospheric chemistry and air pollution on agriculture and natural systems (e.g. marine, natural vegetation) as well as feedbacks between the atmosphere and ecosystems.

This session highlights the future of atmospheric chemistry. This includes the development of new approaches, new tools, and new solutions to advancing research in our field and at the intersection with other communities. Key questions posed by this session are: what observations (laboratory, in situ field, and satellite based remote sensing) are needed over what time scales (campaign to long term) to advance our understanding of atmospheric chemistry? How can new measurements best be used by models? What new modeling and analysis techniques will help advance our science? How can we expand the evidence base needed for policy-making?