Missing in total OH reactivity of VOCs from gasoline evaporation

Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds (VOCs). Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparative reactivity method (CRM) using proton transfer reaction mass spectrometer (PTR-MS). Compositions of 56 PAMS (photochemical assessment monitoring station) nonmethane hydrocarbons (NMHCs) were measured for both liquid and headspace of gasoline. We found high abundance of alkenes and aromatics in gasoline. The calculated OH reactivity derived from quantified NMHCs speciation accounted for only 57 4% of total reactivity obtained from CRM method. N-Alkenes, only 6 wt% in liquid gasoline, contributed to 70% of calculated reactivity. We assume that the undetected branched alkenes are the possible reason for the missing reactivity. We suggest that the priority of gasoline quality improvement is to reduce alkenes content in gasoline in term of reactivity-based control. (C) 2015 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.National Natural Science Foundation [41125018, 41330635]SCI(E)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)ARTICLEmshao@pku.edu.cn101246-12482