太原市城区夏季VOCs来源及其对O3生成的贡献

采集太原市城区夏季VOCs样品并分析其浓度特征，使用参数修正法得到VOCs初始浓度，分析其来源及对O₃生成的贡献.结果显示：太原市城区总VOCs平均浓度为48.13 μg/m³，烷烃（25.52 μg/m³）为主要组分.VOCs浓度呈明显日变化特征，在日间（10：00~14：00）光化学产生O₃的关键时段浓度最低.油品挥发、机动车排放、燃煤、植物排放与液化石油气/天燃气（LPG/NG）使用源对修正后环境VOCs的贡献分别为26.89%、25.55%、21.14%、14.99%、11.44%，对O₃生成的贡献分别为21.44%、33.10%、24.07%、13.77%、7.62%.机动车为新鲜排放气团VOCs的重要来源，而油品挥发、燃煤的输送与本地积累是其他（混合、夜间与反应）气团VOCs的重要来源.机动车排放、油品挥发与燃煤为VOCs与O₃生成的重要贡献源，控制此类源排放可减少太原市城区环境VOCs浓度并有效降低O₃生成.

Source apportionment of VOCs and its contribution to O3 production during summertime in urban area of Taiyuan

Air samples were collected to obtain the observed concentration of VOCs during summertime in the urban area of Taiyuan. A photochemical age-based parameterization method was applied to obtain the initial concentration of VOCs. Then the sources of VOCs were identified and the potential sources of O₃ were analyzed. The average concentration of total VOCs was 48.13μg/m³ with the most abundant group of alkanes (25.52μg/m³). VOCs concentration shows a distinct diurnal variation with the lowest value in the critical time for photochemical reaction during daytime (10:00~14:00). Oil evaporation, vehicle emissions, coal combustion, biogenic emission and liquefied petroleum gas/natural gas (LPG/NG) usage were the major sources of summertime VOCs in urban area of Taiyuan, with the relative contribution of 26.89%, 25.55%, 21.14%, 14.99%, and 11.44% for VOCs sources, while their contributed to the O₃ productionwere 21.44%, 33.10%, 24.07%, 13.77%, and 7.62% respectively. Local vehicle exhaust was the main contributor of VOCs in airmass with fresh emission characteristics, while oil evaporation and coal combustion mainly contributed to VOCs in airmasses characterized by mixed, nocturnal, and aged after oxidation reaction through transport and local accumulation. To sum up, vehicle emissions, coal combustion and oil evaporation were the major contributors of ambient VOCs and O₃ production, while reduction the emissions of these sources can reduce the concentration level of ambient VOCs and effectively alleviate O₃ production.