Deposited Biomass Burning Aerosol as a Possible Source of Reactive Species to Air-Exposed Surface Films

DOUGLAS COLLINS, April Hurlock, Naomi Douek, Bucknell University

     Abstract Number: 410
     Working Group: Biomass Combustion: Outdoor/Indoor Transport and Indoor Air Quality

Abstract
Multiphase chemical reactions can lead to the production/emission of trace gases and alterations to the chemical composition of the condensed phase. In consideration of the long-term aging of air-exposed surface films, one must consider the range of possible reactive species, and studies have focused heavily on gaseous oxidants. Aerosol particles from combustion sources have the potential to harbor reactive oxygen species, as evidenced by measurements of their oxidative potential. Recognizing the chemical role of reactive oxygen species from aerosol particles when deposited in or on biological subjects, we sought to establish the potential for deposited aerosol particles to deliver oxidants to environmental surfaces, such as those inside buildings. Using a non-volatile antioxidant, tris(carboxyethyl) phosphine (TCEP), to make a thin film on a horizontal surface, it was found that the deposition of side-stream tobacco smoke particles caused oxidation reactions to occur in a small laboratory chamber. Similar experiments were conducted in which the TCEP film was replaced with other organic chemicals, each having different functional groups, including oleic acid, bis(ethylhexyl) sebacate, bisphenol A, and squalene. From these initial tobacco smoke studies, investigations were extended to the oxidation of organic surface films upon the deposition of biomass burning particles. Our studies suggest that the delivery of reactive oxygen species to surfaces by deposited particles should be considered in environments that are impacted by significant particulate matter pollution. These studies set the stage for a more comprehensive consideration of the chemical aging of environmental surface films both indoors and outdoors.