| 南京市南部地区O3污染特征、生成敏感性及传输影响分析 |
| 摘要点击 1778 全文点击 442 投稿时间：2022-07-16 修订日期：2022-10-20 |
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| 中文关键词 O3-VOCs-NOx敏感性 基于观测的模型(OBM) 潜在源区分析 传输影响 南京 |
| 英文关键词 O3-VOCs-NOx sensitivity observation-based model (OBM) potential source analysis transport impact Nanjing |
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| 中文摘要 |
| 作为中国最重要的城市群之一,近年来长江三角洲(YRD)地区大气臭氧(O3)污染问题突出.于2020年7~9月和2021年4~5月在南京市南部地区溧水站点开展了大气O3、氮氧化物(NOx)和挥发性有机物(VOCs)等污染物的在线观测.在此基础上分析了溧水站点O3的污染特征并与城区站点进行比较,发现溧水站点O3污染较城区站点更加严重.在观测期间选择了3次典型的O3污染过程,分别为2020年8月16~27日、2020年9月3~11日和2021年5月17~25日.利用基于观测的模型(OBM)分析了这3次污染过程的O3-VOCs-NOx敏感性.基于OBM所模拟的O3前体物相对增量反应性(RIR)和NOx和VOCs削减情景下O3生成等值线(EKMA曲线)结果显示,3次污染过程中O3-VOCs-NOx敏感性分别处于NOx控制区、协同控制区和VOCs控制区.这一差异可能与传输影响有关,因此进一步利用潜在源贡献函数(PSCF)和浓度权重轨迹(CWT)分析了3次污染过程中NOx、VOCs和O3的潜在源区.结果显示不同污染过程的NOx、VOCs和O3和潜在源区位置存在差异,分别受到了溧水点东部、南京市城区和安徽省东部、南京城区和长三角中部的影响.传输对O3及其前体物的影响也表明了区域联防联控在长三角O3污染防控中的必要性. |
| 英文摘要 |
| As one of the most important city clusters in China, surface ozone (O3) pollution in the Yangtze River Delta (YRD) Region has become a prominent air quality problem in recent years. Online observations of ambient O3, nitrogen oxides (NOx), and volatile organic compounds (VOCs) were conducted in southern Nanjing from July-September 2020 and April-May 2021. On this basis, the pollution characteristics of O3 were analyzed. The O3-VOCs-NOx sensitivity and the transport influence of its precursors were further discussed using models. The frequency statistics of the daily maximum 8-hour moving average (DMA-8h O3) and hourly concentration (O3-1h) showed that O3 pollution in southern Nanjing was more serious than that in urban areas. Three typical O3 pollution episodes were selected during the whole observation period, which included August 16th-27th, 2020; September 3rd-11th, 2020; and May 17th-25th, 2021. The O3-VOCs-NOx sensitivities in these three pollution episodes were analyzed using the observation-based model (OBM). The results of the relative incremental reactivity (RIR) and empirical kinetics modeling approach (EKMA) showed that the sensitivities of O3 formation in the three pollution episodes were in the NOx-limited regime, the transition regime, and the VOCs-limited regime, respectively. This difference in O3-VOCs-NOx sensitivity reflects that the site may have been influenced by transport. Therefore, the potential source contribution function (PSCF) and the concentration weighted trajectory (CWT) method were further used to analyze the potential source areas of NOx, VOCs, and O3 in these three pollution episodes. The results showed that there were obvious regional transport effects of NOx, VOCs, and O3 in these three pollution episodes. The location of potential sources differed in these three pollution episodes, which were affected by the eastern cities of the Lishui site; the urban area of Nanjing and eastern area of Anhui Province; and the urban area of Nanjing and the middle of the YRD Region, respectively. The impact of transport on O3 and its precursors also indicated the necessity of regional joint prevention and control of O3 pollution in the YRD Region. |
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