Organic aerosols make up a significant fraction of the atmospheric particulate matter. They affect urban air quality, visibility, and global climate. What makes the representation of organic aerosols in air pollution models especially challenging is their highly-dynamic nature. They continuously change their chemical composition and physical properties as a result of various 'aging' processes, including reactions of aerosol compounds with reactive oxygen species, direct photolysis, oligomerization reactions, hydrolysis, etc. This presentation will discuss the effects of particle-phase and aqueous-phase aging processes on the molecular level chemical composition of secondary organic aerosols (SOA) investigated with state-of-the-art methods of high resolution mass spectrometry. Photochemical aging of SOA will be contrasted with 'dark' aging processes, which occur without involvement of solar radiation and free radicals. The presentation will emphasize the formation of previously-unrecognized types of organic compounds in aged SOA with unusual properties, such light-absorbing nitrogen-containing organic compounds. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/240nm/uploads/31824_untitled.jpg' alt='' />

Photochemical and dark aging of secondary organic aerosols

247th National Meeting (2014)

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