Building upon the introductory understanding of atmospheric chemistry provided in CHM210H1, this course develops a quantitative description of chemical processes in the atmosphere. Modern research topics in the field are discussed, such as aerosol chemistry and formation mechanisms, tropospheric organic chemistry, the chemistry of climate including cloud formation and geoengineering, biosphere-atmosphere interactions, and the chemistry of remote environments. Mathematical models of atmospheric chemistry are developed; reading is from the scientific literature; class discussion is emphasized.