In situ Ozone Production is highly sensitive to Volatile Organic Compounds in the Indian Megacity of Delhi
In situ Ozone Production is highly sensitive to Volatile Organic Compounds in the Indian Megacity of Delhi
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DOI：
10.5194/acp-2021-278
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发表时间：
2021-04
影响因子：
6.3
通讯作者：
Beth S. Nelson;G. Stewart;Will S. Drysdale;M. Newland;A. Vaughan;R. Dunmore;Pete M. Edwards;
中科院分区：
文献类型：
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作者：
Beth S. Nelson;G. Stewart;Will S. Drysdale;M. Newland;A. Vaughan;R. Dunmore;Pete M. Edwards;
抽象。印度大城市德里的空气质量是世界上最差的。虽然环境中的NO2和颗粒物（PM）浓度在城市中受到了相当大的关注，但高地面臭氧（O3）浓度往往是污染的一个被忽视的组成部分。O3可导致严重的生态系统破坏，农作物损失，并对人类健康产生不利影响。在2018年10月期间，在旧德里的一个城市站点连续测量了物种非甲烷碳氢化合物挥发性有机化合物（C2 - C13），含氧挥发性有机化合物（o-VOCs），NO，NO2，HONO，CO，SO2，O3和光解率的浓度。这些观察结果用于约束利用主化学机制v3.3.1的详细化学盒模型。VOCs和NOx（NO + NO2）在模型中变化，以测试其对当地的O3生产率，P（O3），这揭示了VOCs有限的化学制度的影响。当只减少NOx浓度时，观察到P（O3）的显着增加，因此在污染减排策略中还必须考虑VOC共同减少方法。在这项工作中检查的VOC中，平均早晨P（O3）速率对单芳香族化合物最敏感，其次是单萜和烯烃，在模型中将其浓度减半，分别导致P（O3）减少15.6%，13.1%和12.9%。P（O3）是不敏感的气溶胶表面积的直接变化，但非常敏感的光解率的变化，这可能会影响未来的PM浓度的变化。根据埃德加v5.0 Global Air Pollutant Emissions和埃德加v4.3.2_VOC_spec清单的描述，VOC和NOx浓度被划分为排放源部门，从而可以研究单个排放源对P（O3）的影响。仅减少道路运输排放，这是全球空气污染减排战略中的一项共同战略，被发现会增加P（O3），即使在完全消除污染源的情况下也是如此。通过减少道路运输沿着以及制造和加工过程中燃烧产生的排放，实现了P（O3）的有效减少。当这些组合源减半时，模拟的P（O3）减少了约20 ppb h−1。这项研究强调了在德里未来的污染减排战略中减少VOCs与NOx和PM的重要性。
Abstract. The Indian megacity of Delhi suffers from some of the poorest air quality in the world. While ambient NO2 and particulate matter (PM) concentrations have received considerable attention in the city, high ground level ozone (O3) concentrations are an often overlooked component of pollution. O3 can lead to significant ecosystem damage, agricultural crop losses, and adversely affect human health. During October 2018, concentrations of speciated non-methane hydrocarbons volatile organic compounds (C2 – C13), oxygenated volatile organic compounds (o-VOCs), NO, NO2, HONO, CO, SO2, O3, and photolysis rates, were continuously measured at an urban site in Old Delhi. These observations were used to constrain a detailed chemical box model utilising the Master Chemical Mechanism v3.3.1. VOCs and NOx (NO + NO2) were varied in the model to test their impact on local O3 production rates, P(O3), which revealed a VOC-limited chemical regime. When only NOx concentrations were reduced, a significant increase in P(O3) was observed, thus VOC co-reduction approaches must also be considered in pollution abatement strategies. Of the VOCs examined in this work, mean morning P(O3) rates were most sensitive to monoaromatic compounds, followed by monoterpenes and alkenes, where halving their concentrations in the model led to a 15.6 %, 13.1 % and 12.9 % reduction in P(O3), respectively. P(O3) was not sensitive to direct changes in aerosol surface area but was very sensitive to changes in photolysis rates, which may be influenced by future changes in PM concentrations. VOC and NOx concentrations were divided into emission source sectors, as described by the EDGAR v5.0 Global Air Pollutant Emissions and EDGAR v4.3.2_VOC_spec inventories, allowing for the impact of individual emission sources on P(O3) to be investigated. Reducing road transport emissions only, a common strategy in air pollution abatement strategies worldwide, was found to increase P(O3), even when the source was removed in its entirety. Effective reduction in P(O3) was achieved by reducing road transport along with emissions from combustion for manufacturing and process emissions. Modelled P(O3) reduced by ~20 ppb h−1 when these combined sources were halved. This study highlights the importance of reducing VOCs in parallel with NOx and PM in future pollution abatement strategies in Delhi.