Atmospheric evolution of emissions from a boreal forest fire: the formation of highly functionalized oxygen-, nitrogen-, and sulfur-containing organic compounds

Abstract. Forest fires are major contributors of reactive gas- and particle-phase organic compounds to the atmosphere. We used offline high-resolution tandem mass spectrometry perform a molecular-level speciation sampled via aircraft from an evolving boreal forest fire smoke plume in Saskatchewan, Canada. observed diverse multifunctional containing oxygen, nitrogen, sulfur (CHONS), whose structures, formation, impacts understudied. The dilution-corrected absolute ion abundance CHONS increased with age by factor 6.4 over first 4 h downwind transport, their relative contribution functionalized aerosol (OA) mixture 19 % 40 %. sulfide functional groups 13 age, OA Sulfides were present up 75 increases sulfides accompanied ring-bound nitrogen; both together prevalence. A complex intermediate- semi-volatile gas-phase species was emissions depleted downwind, representing potential precursors compounds. These results demonstrate formation nitrogen- oxygen-containing biomass burning presence reduced species. In addition, they highlight chemical pathways that may also be relevant situations elevated sulfur-containing residential fossil fuel use (e.g., coal), respectively.