New Science in Air Quality and Climate from Charney to AR6

In the 40 years since the Charney Report to the National Academy of Sciences, Atmospheric Chemistry has progressed from isolated and largely disconnected research communities to an interconnected whole. During that time, advances in instrumentation have repeatedly led to revolutionary advances in our understanding. Forty years ago, there were separate disciplines of global atmospheric chemistry (exemplified by the ground-breaking publication of Logan et al 3 years after the Charney Report); local air pollution and air-quality engineering focused on photochemical smog; and climate science. Now we understand the connections between all of these, with the global role of air pollution, especially fine particles, driven by progressive oxidation chemistry associated with global atmospheric chemistry leading directly to the leading climate uncertainties of forcing associated with light scattering by particles and clouds.

In both computational and observational atmospheric science, resolution is a critical but still poorly understood parameter. Human exposure to air pollution varies over scales of 100 m or less, and key length scales in clouds are equally small, yet transport and chemistry occurs on a global scale as well. Our ability to observe and simulate dynamics, composition and chemistry over this wide range of scales is growing rapidly. Likewise, we are gaining a progressively more refined view of the relationships between gas- and condensed-phase atmospheric constituents, and how that cocktail may influence human health, particle formation, and climate. The connections between those areas, recent advances in each, and remaining key unknowns form the core of this meeting.