Characterizing the level, photochemical reactivity, emission, and source contribution of the volatile organic compounds based on PTR-TOF-MS during winter haze period in Beijing, China
Characterizing the level, photochemical reactivity, emission, and source contribution of the volatile organic compounds based on PTR-TOF-MS during winter haze period in Beijing, China
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DOI：
10.1016/j.atmosres.2018.05.005
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发表时间：
2018-11
影响因子：
5.5
通讯作者：
Jiu-jiang Sheng;Delong Zhao;D. Ding;Xia Li;Mengyu Huang;Yang Gao;J. Quan;Qiang Zhang
中科院分区：
文献类型：
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作者：
Jiu-jiang Sheng;Delong Zhao;D. Ding;Xia Li;Mengyu Huang;Yang Gao;J. Quan;Qiang Zhang
大气中挥发性有机物（VOCs）是二次有机气溶胶形成及其它大气光化学过程的主要参与者。然而，目前对北方大气中VOCs的研究还远未达到一个清晰的认识。在这项研究中，使用质子转移反应飞行时间质谱仪（PTR-TOF-MS）在2016年12月的冬季雾霾期间在北京市中心地区测量了VOCs。雾霾天VOC的平均混合比为（ppb）：甲醇（51.75）、甲醛（41.65），乙醛（15.81），丙酮（7.92），C8-芳烃（7.35）、甲苯（6.11）、苯（4.30）、MEK（2.53）、乙腈（2.05）、C9-芳族化合物（1.54）、苯甲醛（1.12）、异戊二烯（1.00）、苯乙烯（0.62）。这些集中代表了世界各地城市中最大的价值。挥发性有机物浓度变化剧烈，最大值主要出现在扩散条件最弱的日子。由于这一时期太阳辐射的不同，VOCs的光化学反应性分别在霾日和晴天出现最小值和最大值。主要人为排放贡献了大多数VOCs混合比的一半以上。而甲醛则有56.6%的贡献来自于次生或生物源，并且这种贡献主要在中午阳光较强时增加。
The atmospheric volatile organic compounds (VOCs) are the key participators in the formation of secondary organic aerosol and other atmospheric photochemical processes. However, it is still far from clear understanding of the VOCs in Northern China. In this study, VOCs were measured using a proton transfer reaction-time of flight-mass spectrometer (PTR-TOF-MS) in the downtown area of Beijing during a winter haze period in December 2016. The average mixing ratios of VOCs on the haze days were (ppb): methanol (51.75), formaldehyde (41.65), acetaldehyde (15.81), acetone (7.92), C8-aromatics (7.35), toluene (6.11), benzene (4.30), MEK (2.53), acetonitrile (2.05), C9-aromatics (1.54), benzaldehyde (1.12), isoprene (1.00), styrene (0.62). These concentrations represented the largest values among the cities around the world. VOC concentrations varied dramatically, with the largest value mainly appeared on days having the weakest diffusion condition. Due to the different solar radiation in this period, the photochemical reactivity of the VOCs showed the minimum and maximum values on haze and clear days, respectively. The primary anthropogenic emissions contributed more than half of the mixing ratios of most VOCs. However, formaldehyde received 56.6% contribution from the secondary or biogenic sources, and this contribution mainly increased at the noon hours when sunlight was stronger.