In situ ozone production is highly sensitive to volatile organic compounds in Delhi, India
In situ ozone production is highly sensitive to volatile organic compounds in Delhi, India
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DOI：
10.5194/acp-21-13609-2021
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发表时间：
2021-09-13
影响因子：
6.3
通讯作者：
Lee, James D.
中科院分区：
文献类型：
--
作者：
Nelson, Beth S.;Stewart, Gareth J.;Lee, James D.
印度大城市德里的空气质量是世界上最差的。虽然环境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（O-3）浓度是一个经常被忽视的污染成分。O-3可导致严重的生态系统破坏和农作物损失，并对人类健康产生不利影响。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烃挥发性有机化合物（C-2-C-13）、含氧挥发性有机化合物（o-VOCs）、NO、NO2、HONO、CO、SO2、O-3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。挥发性有机化合物和氮氧化物（NO C NO2）在模型中变化，以测试其对当地的O-3生产率，P（O-3），这揭示了挥发性有机化合物有限的化学制度的影响。当只有氮氧化物浓度降低，P（O-3）的显着增加，观察到，因此，挥发性有机化合物的共同减少的方法也必须考虑在污染减排战略。在这项工作中检查的挥发性有机化合物，平均上午P（O-3）率是最敏感的单芳香族化合物，其次是单萜和烯烃，其中在模型中的浓度减半导致15.6%，13.1%，和12.9%的减少P（O-3），分别。P（O-3）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，这可能是未来的PM浓度的变化的影响。根据全球大气研究排放数据库（埃德加）v5.0全球空气污染物排放和埃德加v4.3.2_VOC_spec清单的描述，将VOC和NOx浓度划分为排放源部门，以研究单个排放源对P（O-3）的影响。仅减少道路运输排放，这是全世界空气污染减排战略中的一项共同战略，被发现会增加P（O-3），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业燃烧和加工排放，实现了P（O-3）的有效减少。当这些组合源减半时，模拟的P（O-3）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。
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 (O-3) concentrations are an often overlooked component of pollution. O-3 can lead to significant ecosystem damage and agricultural crop losses, and adversely affect human health. During October 2018, concentrations of speciated non-methane hydrocarbon volatile organic compounds (C-2-C-13), oxygenated volatile organic compounds (o-VOCs), NO, NO2, HONO, CO, SO2, O-3, and photolysis rates, were continuously mea- sured 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 C NO2) were varied in the model to test their impact on local O-3 production rates, P(O-3), which revealed a VOC-limited chemical regime. When only NO x concentrations were reduced, a significant increase in P(O-3) 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(O-3) 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(O-3), respectively. P(O-3) 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 Emissions Database for Global Atmospheric Research (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(O-3) to be investigated. Reducing road transport emissions only, a common strategy in air pollution abatement strategies worldwide, was found to increase P(O-3), even when the source was removed in its entirety. Effective reduction in P(O-3) was achieved by reducing road transport along with emissions from combustion for manufacturing and process emissions. Modelled P(O-3) reduced by similar to 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.