Atmospheric Chemistry of Small Molecules and Aerosols in the Anthropocene

In the Anthropocene humans have a global impact on the atmosphere and ecosystems. This became first visible with the discovery that man-made chlorine emissions modify stratospheric ozone (O₃) over South Pole. More recent evidence suggests that atmospheric chemistry of bromine and iodine radicals dominates the relevance of halogens in the troposphere, and may be more active today than 100 years ago. Also, today’s wildfire season is starting earlier, lasts ~3 times longer, and is affecting a larger area than only 20 years ago, yet little is known about the mass of smoke emitted from wildfires. I will discuss examples of analytical advances to measure small molecules (using instruments developed by the Volkamer group in Boulder) that explore innovative ways to better quantify sources, and improve the molecular understanding of atmospheric processes in a changing atmosphere. The presence of small water soluble oxygenated volatile organic compounds (OVOC, e.g., formaldehyde, glyoxal) over oceans has been puzzling researchers for 25+ years. We investigate the source mechanism of marine OVOC at the ocean surface, and their chemical coupling with halogens (i.e., bromine) by combining laboratory experiments, field observations and numerical modeling. Also, the CU Solar Occultation Flux (CU SOF) prototype instrument is designed for use from mobile platforms (e.g., van, aircraft). CU SOF enables us to quantify emissions from wildfires (CO, NH₃, NO_x, HONO, other trace gases), agriculture, and to evaluate atmospheric models used to predict the photochemical O3 and aerosol formation downwind. CU SOF also is useful to quantify and attribute CH₄ emissions from oil & gas production, and agriculture.