Reactivity of ambient volatile organic compounds (VOCs) in summer of 2004 in Beijing

Ambient volatile organic compounds (VOCs) were sampled at six sites in Beijing in the summer of 2004 and analyzed by GCMS. The chemical reactivities of 73 quantified VOCs species were evaluated by OH loss rates (L-OH) and ozone formation potentials (OFPs). Top 15 reactive species, mainly alkenes and aromatics, were identified by these two methods, and accounted for more than 70% of total reactivity of VOCs. In urban areas, isoprene was the most reactive species in term of 011 loss rate, contributing 11.4% to the L-OH Of VOCs. While toluene, accounting for 9.4% of OFPs, appeared to have a long-time role in the photochemical processes. Tongzhou site is obviously influenced by local chemical industry, but the other five sites showed typical urban features influenced mainly by vehicular emissions. (C) 2008 Min Shao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.