Air quality diagnosis from comprehensive observations of total OH reactivity and reactive trace species in urban central Tokyo
Air quality diagnosis from comprehensive observations of total OH reactivity and reactive trace species in urban central Tokyo
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DOI：
10.1016/j.atmosenv.2011.12.029
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发表时间：
2012-03
影响因子：
5
通讯作者：
A. Yoshino;Yoshihiro Nakashima;K. Miyazaki;Shungo Kato;J. Suthawaree;N. Shimo;S. Matsunaga;S. Chatani
中科院分区：
文献类型：
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作者：
A. Yoshino;Yoshihiro Nakashima;K. Miyazaki;Shungo Kato;J. Suthawaree;N. Shimo;S. Matsunaga;S. Chatani
为了诊断2007年夏冬和2009年秋季东京市中心的空气质量，我们进行了一项全面的观测研究，以确定大气化学物质的混合比例和总OH反应性。在每个季节连续测量70多种活性痕量物质的浓度。用激光诱导泵浦和探针技术直接测量了OH的总反应性。观察到的化学物质种类表现出季节变化。NO与CO在冬季呈良好的相关关系，而在夏季呈不相关关系。这表明，在冬季，机动车尾气是东京市中心NO的主要来源，而在夏季，no2的光解作用占主导地位。在夏季和秋季白天观测到的平均总OH反应性值相似（约30 s−1）。夏季VOCs占OH反应性的比例较大，秋季nox占主导地位。我们发现，在夏季，通过VOCs产生氧化剂的光化学过程主导了OH的去除，而在秋季，通过OH和no2的反应产生硝酸的过程占主导地位，绕过了氧化剂的产生途径，导致氧化剂的形成减少。
We have conducted a comprehensive observational study to determine the mixing ratios of atmospheric chemical species and total OH reactivity in central Tokyo, in order to diagnose the air quality during summer and winter 2007 and autumn 2009. Concentrations of over 70 reactive trace species were continuously measured throughout each season. The total OH reactivity was measured directly using a laser-induced pump and probe technique. The observed chemical species exhibited seasonal variations. There was a good correlation between NO and CO in winter, but not in summer. This indicates that during winter, vehicle exhaust provided a significant source of NO in central Tokyo, while photolysis of NO2was dominant in summer. Similar values (approximately 30 s−1) for the averaged total OH reactivity were observed in both summer and autumn during the daytime. However, VOCs accounted for a larger percentage of the OH reactivity in summer, while NOxwas more dominant in autumn. We find that photochemical processes leading to oxidant production via VOCs dominated OH removal in summer, while the production of nitric acid from the reaction between OH and NO2was dominant in autumn, by-passing the oxidant production pathways and resulting in reduced oxidant formation.