Secondary Organic Aerosol Formation Potential of D5-Siloxane, a Major Compound Found in Personal Care Products

Abstract:

Decamethylcyclopentasiloxane (D5-siloxane) is one of the most abundant compounds measured in urban indoor and outdoor air in developed countries. Used in many personal care products, its concentration measured outdoors is correlated with population density. Additionally, particulate matter from urban areas is richer in silicon than less populated areas. The vast majority of the D5-siloxane used escapes into the atmosphere and, once there, its major loss source is to the hydroxyl radical. Experimental and computationally simulated environmental data from chamber experiments of D5-siloxane and OH provide an understanding of aerosol yield and chemistry under relevant urban conditions and give insight into the effect of volatile chemical products on the production of secondary organic aerosol (SOA). Aerosol yields and composition as a function of NO_x concentration are shown.