The concentration of PM2.5, PM10, NO2, NH3, SO2, and CO at site 3 significantly dropped steeply from 242, 205, 85, 10, 9, and 49 μg/m3 as on January 1, 2020 to 20, 28, 9, 1, 7, and 22 μg/m3 during COVID-19 pandemic confinement on May 31, 2020, respectively.