| 基于双维度校验的珠三角区域臭氧生成机制长期时空演化特征识别 |
| 摘要点击 1410 全文点击 1166 投稿时间：2022-01-23 修订日期：2022-04-06 |
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| 中文关键词 臭氧(O3) 臭氧生成机制 VOC活性 长期 时空演化 |
| 英文关键词 ozone (O3) ozone formation mechanism (OFM) volatile organic compounds activity (VOCR) long-term trend spatial-temporal evolution |
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| 中文摘要 |
| 臭氧（O3）污染已经成为我国主要城市区域大气环境的首要污染物，由于其生成与前体物之间呈现高度非线性的关系，O3生成机制的识别对前体物的减排具有基础性的重要作用.针对常规方法难以较好对机制的长期演化特征进行识别问题，基于常规观测数据（O3、NO2）和温度（T）与挥发性有机物活性（VOCR）之间的关系，从NO2和T两个维度对珠三角区域O3的生成机制进行了识别并做校验，分析了2006~2020年期间O3的趋势变化规律和原因，研究了机制的长期演化特征.结果表明，O3浓度随NO2和T水平的升高呈现升高、稳定、下降和再次升高的趋势变化规律，当ρ（NO2）处于0~35、35~45、>45 μg·m-3和T处于>30、25~30、<25℃时，机制分别处于NOx控制区、过渡区和VOCR控制区.不同时间段，随着T升高VOCR随之升高，推动了O3浓度上升.由于前体物排放趋势变化和O3生成机制状况不同，O3浓度在不同时间段和T条件下的趋势变化规律不同.整体上，珠三角区域西部偏VOCR控制区，东部偏过渡区，两个维度机制的识别结果具有较高一致性.随时间变化，西部区域的过渡区向VOCR控制区转变，东部区域的VOCR控制区向NOx控制区转变.在不同时间段，随着T升高O3生成对NOx的敏感性增强，随时间变化，高温和低温条件下O3生成分别对NOx和VOCR的敏感性增强. |
| 英文摘要 |
| Ozone (O3) pollution has become the primary pollutant in the atmospheric environment of major urban areas in China. Due to the highly nonlinear relationship between O3 and its precursors, the identification of the O3 formation mechanism (OFM) is fundamental to emission restraining. An overview of previous related investigations indicated that it is rather difficult to ideally recognize OFM long-term evolutions with conventional methods. In this study, based on the relationship between ambient temperature and volatile organic compound activity (VOCR) and O3 and NO2 conventional observation data from 2006 to 2020 in the Pearl River Delta (PRD), OFM was identified from the two dimensions of NO2 and temperature. Then, OFM was verified to ensure accuracy. Afterward, O3 concentration and OFM in different periods and temperature levels were analyzed. The results showed that O3 concentration presented a trend of increasing, stabilizing, decreasing, and increasing again with the increase in NO2 and temperature levels. Overall, NOx-limited, transitional, and VOCR-limited corresponded to NO2 in 0-35 μg·m-3, 35-45 μg·m-3, and greater than 45 μg·m-3, and temperature ranged from higher than 30℃, 25-30℃, and lower than 25℃, respectively. VOCR increased with the increase in temperature during different time periods, which promoted O3 to a higher level. O3 concentration in different time periods and temperature levels varied with precursor emission fluctuations in different OFM. On average, during 2006 to 2020, VOCR-limited and transitional were in the west and east of PRD, respectively, and OFM identified from NO2 and temperature dimension were consistent. The transitional tended toward the VOCR-limited in the west, and VOCR-limited in the east of PRD tended toward the NOx-limited with time. O3 formation was more related to NOx as temperature increased, and it became more sensitive to NOx and VOCR at high and low temperatures, correspondingly. |
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