2020年1~2月管控期对永春县主要空气污染物的影响

Impact of prevention and control period from January to February 2020 on main air pollutants in Yongchun County

本文选取永春县2020年1月1日~2月29日PM_(2.5)、PM_(10)、O_(3)、NO_(2)、SO_(2)、CO以及温度(T)、相对湿度(RH)、风速(WS)和风向(WD)等环境空气质量和气象参数的在线数据,分析在新冠肺炎疫情防控时城市封锁的情形下,叠加春节假期影响后,永春县空气质量及其主要空气污染物的变化特征。结果表明,管控期间AQI平均值在42~46,与管控前AQI值相比下降了6~8,降幅达到了11%~16%。主要空气污染物PM_(10)和CO的减幅比率更大,分别下降17μg·m^(-3)和0.2 mg·m^(-3),地面扬尘和道路机动车出行的本地一次人为排放源是主要原因;PM_(2.5)由于受二次转化的影响更大,可能抵消了一次排放的贡献,因而与本地排放较少的NO_(2)和SO_(2)表现相似;管控期O_(3)-8 h浓度为61.8±19.9μg·m^(-3),比管控前下降10μg·m^(-3),削峰比率达到了24.6%,而生产生活复苏后反弹了18μg·m^(-3),出现“削峰填谷”现象。因此,主要空气污染物之间时空分布规律及其对不同管控情形下的表现特征,揭示了O_(3)和PM_(2.5)的复合污染状况及其协同控制的复杂性。

This paper selects the online data of PM_(2.5)、PM_(10)、O_(3)、NO_(2)、SO_(2)、CO and temperature(T),relative humidity(RH),wind speed(WS)and wind direction(WD),etc.ambient air quality and meteorological parameters from January 1 to February 29,2020,analyze the change characteristics of air quality and its main air pollutants in Yongchun County under the urban blockade during COVID-19 prevention and control,and after superimposing the impact of the Spring Festival Holiday.The results showed that average value of AQI was 42~46 during the control period,which was 6~8 lower than that before the control,with a decrease of 11%~16%.The reduction ratio of pollutants PM_(10) and CO was greater,decreased by 17μg·m^(-3) and 0.2 mg·m^(-3) respectively.Ground dust and local primary anthropogenic emission sources of road motor vehicle travel were the main reasons,PM_(2.5) was more affected by secondary transformation,it may offset the contribution of primary emission.Therefore,it was similar to the performance of NO_(2) and SO_(2) with less background emission.The concentration of O_(3)-8h in the control period was 61.8±19.9μg·m^(-3),which was 10μg·m^(-3) lower than that before control,and the peak shaving ratio reached 24.6%.After the recovery of production and life,it rebounded by 18μg·m^(-3),resulting in the phenomenon of“peak shaving and valley filling”.So the temporal and spatial distribution law of main air pollutants and their performance characteristics under different control conditions reveal O_(3) and PM_(2.5) and the complexity of its collaborative control.