Annual and seasonal variations in the ambient air quality parameters at Kalpakkam site (2022–2023)

This first-time study aims at the assessment of ambient air quality patterns in Kalpakkam, a coastal rural site of South India. The variations in the ambient concentrations of air pollutants such as particulate matter (PM 10 and PM 2.5 ) and gaseous pollutants (sulfur dioxide [SO 2 ], nitrogen dioxide [NO 2 ], and carbon monoxide [CO]) at the site are analyzed for the period of 2022–2023. This study analyses the changes in concentrations of air pollutants – PM 10 , PM 2.5 , SO 2 , NO 2 , and CO for a period of 2 years (2022–2023). The long-term observations reveal that the particulate matter and gaseous pollutant concentrations have never exceeded the permissible National Ambient Air Quality Standards (Central Pollution Control Board) standards at our site. Nevertheless, pollutants are present in lower levels in summer due to the influence of sea breeze, while the highest levels are seen in the winter months attributed to stable meteorological conditions observed in the site. Particulate matter PM 10 and PM 2.5 had annual averages of 32 μg/m 3 and 21 μg/m 3 in 2022 and 30 μg/m 3 and 18 μg/m 3 in 2023. In 2022, the average SO 2 concentration was 7 μg/m 3 and 3 μg/m 3 in 2023. The average CO concentration was 0.3 mg/m 3 in 2022 and 0.2 mg/m 3 in 2023. Lastly, the average NO 2 concentration was 11 μg/m 3 in 2022 and 8 μg/m 3 in 2023. The Air Quality Index calculated from these observations shows a dominance of good category days throughout the study period here in the site.