广州市大气污染物对新冠疫情管控的响应

The Response of Atmospheric Pollutants to COVID-19 Lockdown in Guangzhou

  • 摘要: 为评估极端污染减排情境下广州市大气污染物的响应特征,结合气象要素和出行指数,分析了2020年新冠疫情停工前后大气污染物时空变化特征。2020年疫情停工期(1月24日—2月9日)气象条件与2017—2019年同期相比,大气水平扩散条件未见显著性差异,湿清除条件较好,生成O3的光化学反应条件较差,NO2、PM10、PM2.5、SO2和CO浓度达2017年以来同期最低值,O3浓度则处于2017年以来的次低值。相似气象条件下,全市6项大气污染物在停工期的浓度均比停工前和复工期低。其中,NO2、PM10和PM2.5对疫情管控的响应较灵敏,SO2和CO的响应较弱;由于受气象条件和气态前体物的共同作用,O3浓度在停工前后的变化显得较为复杂,变化幅度较小。城区大气污染物对管控的响应比郊区大,而在大气污染排放较为集中的工业园区,响应比城郊区更加灵敏。对严控措施响应较敏感的污染物NO2和PM10,其浓度均与出行强度/风速的相关系数分别为0.87和0.74,呈现较强的正相关关系。

     

    Abstract: In order to evaluate the effect of air pollution emission reduction in Guangzhou,the temporal and spatial variation characteristics of air pollutants before and after the COVID-19 lockdown period were analyzed combined with meteorological elements and travel intensity.Compared with the same period of 2017 to 2019,the meteorological conditions of the lockdown period (January 24 to February 9) showed no significant difference in atmospheric horizontal diffusion conditions,better wet removal conditions and worse ozone generation meteorological conditions.The concentrations of NO2,PM10,PM2.5,SO2 and CO reached the lowest value,and the concentration of O3 was at the second lowest value since 2017 for the same period.Under similar meteorological conditions,the concentrations of six air pollutants during the lockdown period were all lower than those before the lockdown period and during the resumption period.Among them,NO2,PM10 and PM2.5 were more sensitive to the epidemic control,while SO2 and CO were relatively weak.Due to the combined action of meteorological conditions and gaseous precursors,the change of O3 concentration before and after shutdown appeared to be more complicated,and showed lower range of change.The response of air pollutants to epidemic control varied in different regions.The response of air pollutants to epidemic in urban areas control was greater than that in suburban areas,while in industrial parks with concentrated air pollution emissions,the response became more sensitive than that in both urban and suburban areas.NO2 and PM10 were more sensitive to strict control measures,the correlation coefficients between their concentrations and travel intensity/wind speed were 0.87 and 0.74,respectively,showing a strong positive correlation.

     

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