Investigating the background and local contribution of the oxidants in London and Bangkok.
Investigating the background and local contribution of the oxidants in London and Bangkok.
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DOI：
10.1039/d0fd00086h
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发表时间：
2020-11
影响因子：
3.4
通讯作者：
M. Khan;Rayne Holland;A. Foulds;J. Matthews;Sanjeevani Panditharatne;Michael E. Jenkin;D. Lowe;P. Navasumrit;C. Percival;D. Shallcross
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文献类型：
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作者：
M. Khan;Rayne Holland;A. Foulds;J. Matthews;Sanjeevani Panditharatne;Michael E. Jenkin;D. Lowe;P. Navasumrit;C. Percival;D. Shallcross
NOx排放和背景O3的来源和分区的氧化剂[OX（= O3 + NO2）]在马里波恩路网站在伦敦在2000年代和2010年代的贡献进行了调查，看看符合伦敦市长的空气质量战略的控制措施或技术变化的影响。污染物排放的减少对本地和背景氧化剂[OX]L和[OX]B的趋势产生了影响，从2000年到2019年，每年分别下降1.4%和0.4%。我们还将我们的研究扩展到另一个大城市曼谷的三个路边站点（Din Daeng，Thonburi和Chokchai），以比较[OX]L和[OX]B及其在Marylebone路站点的行为变化。[OX]L和[NOx]B（0.21[NOx]和32 ppbv）与泰国路边站点（0.12[NOx]至0.26[NOx]和29至32 ppbv）相当。[OX]B水平的季节变化显示春季最大值为伦敦，这是由于较高的北方半球臭氧基线，但在旱季最大值为曼谷，这可能是由于区域规模的长距离传输从亚洲大陆。伦敦和曼谷路边站点的[OX]L的日变化证实了道路运输排放的氧化剂的主导地位，这被认为是整个白天更高。WRF-Chem-CRI模型对[OX]分布的模拟表明，与实测[OX]水平相比，该模型在预测[OX]水平时对伦敦背景站点表现良好，表明该模型正确处理了氧化剂的化学性质。然而，在交通站点的模型测量[OX]水平存在很大的差异，因为在特大城市的大型道路网络中对正在发生的复杂的子网格尺度动态进行[OX]建模存在困难，无论是在大气过程还是在时变源（如交通量）方面。对于路边站点在曼谷，[OX]的变化趋势预测模型正确，但高估了绝对幅度。我们认为，这种大的偏差可能是由于埃德加排放清单（排放高估）超出了模型的分辨率的差异。
The contribution of NOx emissions and background O3 to the sources and partitioning of the oxidants [OX (= O3 + NO2)] at the Marylebone Road site in London during the 2000s and 2010s has been investigated to see the impact of the control measures or technology changes inline with the London Mayor's Air Quality Strategy. The abatement of the pollution emissions has an impact on the trends of local and background oxidants, [OX]L and [OX]B, decreasing by 1.4% per year and 0.4% per year, respectively from 2000 to 2019. We also extend our study to three roadside sites (Din Daeng, Thonburi and Chokchai) in another megacity, Bangkok, to compare [OX]L and [OX]B and their behavioural changes with respect to the Marylebone Road site. [OX]L and [OX]B at the Marylebone Road site (0.21[NOx] and 32 ppbv) are comparable with the roadside sites of Thailand (0.12[NOx] to 0.26[NOx] and 29 to 32 ppbv). The seasonal variation of [OX]B levels displays a spring maximum for London, which is due to the higher northern hemispheric ozone baseline, but a maximum during the dry season is found for Bangkok which is likely due to regional-scale long-range transport from the Asian continent. The diurnal variations of [OX]L for both London and Bangkok roadside sites confirm the dominance of the oxidants from road transport emissions, which are found to be higher throughout the daytime. WRF-Chem-CRI model simulations of the distribution of [OX] showed that the model performed well for London background sites when predicting [OX] levels compared with the measured [OX] levels suggesting that the model is treating the chemistry of the oxidants correctly. However, there are large discrepancies for the model-measurement [OX] levels at the traffic site because of the difficulties in the modelling of [OX] at large road networks in megacities for the complex sub grid-scale dynamics that are taking place, both in terms of atmospheric processes and time-varying sources, such as traffic volumes. For roadside sites in Bangkok, the trend in changes of [OX] is predicted by the model correctly but overestimated in absolute magnitude. We suggest that this large deviation is likely to be due to discrepancies in the EDGAR emission inventory (emission overestimates) beyond the resolution of the model.