2020年珠三角O3污染特征及主要成因

采用珠三角常规空气污染物与成分监测数据,通过分析对比2020年不同阶段的污染物浓度与气象等数据,研究了2020年珠三角臭氧污染特征与其主要成因。结果表明,2020年各月珠三角超标天首要污染物是O₃,珠三角2020年O₃评价浓度为148μg/m³,同比下降16%,AQI达标率同比上升9.5%。2020年O₃污染相对严重的月份是4、8~11月,对应的月度O₃评价浓度分别达到175,164,166,171,162μg/m³,均超过国家二级标准;其它月份均达标,6~12月O₃污染情况同比改善明显,O₃污染减轻使AQI达标率同比上升明显。2020年一季度受春节假期和疫情因素等共同影响,大气污染物排放量明显减少,但O₃浓度下降不明显,主要由于日照时数同比上升约19%;4月全面复工复产,以及辐射相对较强的气象条件,使O₃评价浓度同比上升约58%;5~8月“百日服务”与9~12月“百日行动”采取的污染防治措施有效降低O₃前体物排放量,NO₂浓度同比下降了22%~23%,VOCs浓度下降了18%~26%,使2个阶段的O₃评价浓度均同比下降了20%左右。

Characteristics and main causes of ozone pollution in the Pearl River Delta in 2020

Based on the regulatory monitoring of atmospheric pollutants and components and meteorological data, the characteristics and main causes of ozone pollution in the Pearl River Delta (PRD) in 2020 were studied and analyzed. The results showed that ozone was the primary air pollutant in each month in the PRD in 2020. The annual concentration of ozone was 148mg/m³, decreased by 16% on a year-on-year basis, and the AQI compliance rate increased by 9.5%. The months with relatively serious ozone pollution in 2020 were April, August to November. The corresponding monthly ozone concentrations reached 175, 164, 166, 171 and 162mg/m³, respectively, all exceeding the national air quality standard of the secondary level of 160mg/m³. In other months, the ozone concentrations met the standard. From June to December, the ozone pollution conditions improved significantly compared in 2019, and thus increased the AQI compliance rate significantly year-on-year. In the first quarter of 2020, the emission of air pollutants decreased significantly due to the Spring Festival holiday and epidemic factors. However, the decrease in ozone concentration was not obvious, mainly because of a yearly increase in sunshine hours by about 19%. The comprehensive resumption of work and production in the PRD in April and the meteorological conditions with relatively strong radiation increased the ozone concentration by about 58% year-on-year. The pollution control measures taken in the “100-day service” from May to August and the “100-day action”from September to December effectively reduced the emission of ozone precursors. The concentration of NO₂ decreased by 22%~23% and the concentration of VOCs decreased by 18%~26%, resulting in the concentration of ozone in these two stages decreasing by about 20% year-on-year.