Impact of lockdown due to COVID 19 outbreak on O3 and its precursor gases, PM and BC over North-East India

Abstract:

The air quality over the Eastern Himalayan region during the lockdown period (24 March -3 May 2020) because of COVID 19 outbreak in India with reference to the same period in previous years 2015-2019, is investigated. For that, Copernicus Atmosphere Monitoring Service (CAMS) retrieved concentrations of surface level O₃, NOx, CO, SO₂, PM and BC are being used. Measurements made at Dibrugarh complements the CAMS observations. The positive impact of the lockdown is to considerably reduce the level of O₃ precursor gases and PM and BC. Similar decrement is observed in Dibrugarh in 2020 over their reference levels. The variations are ascribed to the near total absence of anthropogenic activities only, specially the vehicular movement. However, the positivity is somewhat diluted by the simultaneous increase in O₃, a major pollutant. The air quality over the region improved from moderate to satisfactory levels due to the lockdown. The fact that forced reduction in anthropogenic activity can mitigate the negative effect of pollution on climate a great deal is to be taken in right perspective by policy planners and governments.