Temporal Analysis of Atmospheric Pollutant Concentrations with Specific Regard to NAAQS Compliance in an Industrial Cluster of New Delhi, India

The present study focuses on determining the post COVID 19 status of air pollution and temporal variability of pollutants over the Okhla industrial area, New Delhi. The 24 hourly concentration datasets of PM₁₀, PM_2.5, NO₂ and SO₂, for the period of November 2021 to November 2022 were collected from continuous ambient air quality monitoring station of study area. During the study period, the concentration of PM₁₀ and PM_2.5 was observed to be varying from 9.73 to 640.14 µg/m³ and 6.18 to 448.06 µg/m³, respectively. The average values of PM₁₀ and PM_2.5 were recorded as 236.57 and 107.33 µg/m³, respectively; which were much higher than the standard values of Central Pollution Control Board. In case of gaseous pollutants, the mean value of SO₂ was recorded as 9.31 µg/m³ which was much lesser as compared to the set standards. Contrary, the values for NO₂ varied from 14.75 to 219.36 µg/m³ and these values were on the higher side when compared with standards. The Bivariate plots were also drawn to examine the role of wind speed and wind direction in the study area. The results revealed that at low wind speed, high concentrations were prevailing and potential sources of pollutant are in south east direction. Overall, the results of this study highlighted that situation is alarming after COVID 19, and need immediate intervention for the abatement of air pollution in studied region.