Characterizations of volatile organic compounds during high ozone episodes in Beijing,China |
| |
Authors: | An Jun-lin Wang Yue-si Wu Fang-kun Zhu Bin |
| |
Institution: | 1.Key Laboratory of Meteorological Disaster of Ministry of Education, School of Atmospheric Physics,Nanjing University of Information Science & Technology,Nanjing,China;2.Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,China |
| |
Abstract: | Air samples were collected in Beijing from June through August 2008, and concentrations of volatile organic compounds (VOCs)
in those samples are here discussed. This sampling was performed to increase understanding of the distributions of their compositions,
illustrate the overall characteristics of different classes of VOCs, assess the ages of air masses, and apportion sources
of VOCs using principal compound analysis/absolute principal component scores (PCA/APCS). During the sampling periods, the
relative abundance of the four classes of VOCs as determined by the concentration-based method was different from that determined
by the reactivity approach. Alkanes were found to be most abundant (44.3–50.1%) by the concentration-based method, but aromatic
compounds were most abundant (38.2–44.5%) by the reactivity approach. Aromatics and alkenes contributed most (73–84%) to the
ozone formation potential. Toluene was the most abundant compound (11.8–12.7%) during every sampling period. When the maximum
incremental reactivity approach was used, propene, toluene, m,p-xylene, 1-butene, and 1,2,4-trimethylbenzene were the five
most abundant compounds during two sampling periods. X/B, T/B, and E/B ratios in this study were lower than those found in
other cities, possibly due to the aging of the air mass at this site. Four components were extracted from application of PCA
to the data. It was found that the contribution of vehicle exhaust to total VOCs accounted for 53% of VOCs, while emissions
due to the solvent use contributed 33% of the total VOCs. Industrial sources contributed 3% and biogenic sources contributed
11%. The results showed that vehicle exhausts (i.e., unburned vehicle emissions + vehicle internal engine combustion) were
dominant in VOC emissions during the experimental period. The solvent use made the second most significant contribution to
ambient VOCs. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|