Variation of ambient air pollutants and their impacts on Kanpur city, India, during 2016–2020

The present study evaluates the annual and seasonal trends of PM₁₀, NO₂, and SO₂ for eight monitoring stations namely Kidwai Nagar (S1), Jareeb Chowki (S2), Panki Site 1 (S3), Shastri Nagar (S4), Awas Vikas Kalyanpur (S5), Dada Nagar (S6), IIT Campus (S7) and Rama Devi (S8) in Kanpur city, India for the period 2016–2020. It was observed that the annual average concentrations of RSPM, NO₂, and SO₂ varied from 100.40 to 307.50, 9.69–60.74, and 2.00–12.04 µg/m³, respectively, for the study period, indicating that the pollutants exceeded the prescribed standards except SO₂ at all the study locations. Seasonal analysis shows that the minimum and maximum concentrations of RSPM existed for monsoon and winter, varying between 56.14 and 372.64 µg/m³, respectively. Seasonal analysis for gaseous pollutants (SO₂ and NO₂) showed minimal variations with concentration ranges between 2.00–10.97 and 12.56–57.66 µg/m³, respectively. This could be attributed to constant emission sources and year-round industrial operations prevalent within the city. Exceedance factors based on RSPM and NO₂ indicated that PM₁₀ was the most critical pollutant for Kanpur city. Results obtained from the HYSPLIT model depicted poor measures of air quality in the city, with winds blowing from a northerly direction, leading to increased concentration of pollution that exceeded the NAAQS standards. A critical discussion of the results obtained has been presented.