Spatio-seasonal variation in ambient air pollutants and influence of meteorological factors in Coimbatore, Southern India

Air quality is used worldwide to confirm the current status of air pollution level and associated health risks to the public. Several air pollutants reach very high concentrations in many regions across India. In this study, air pollutants were measured in an urban city of Coimbatore, Tamil Nadu, Southern India, during 2013 to 2014 based on season and location, and the influence of meteorological factors. Air pollutants (PM10, PM2.5, SO2, NO2, CO, and O3) across eight locations including industrial, residential, traffic, and commercial areas were assessed. The results showed that PM10, PM2.5, and CO were the most serious pollutants and their average concentrations ranged from 65.5 to 98.6 μg/m3, 27.6 to 56.9 μg/m3, and 1.58 to 8.21 mg/m3, respectively, among various locations. Significantly higher concentration of air pollutants was recorded in industrial areas followed by traffic and commercial areas. Comparatively higher mean concentration of O3 (2.22 ± 0.75 μg/m3) and CO (7.73 ± 1.86 mg/m3) was recorded during the summer season, whereas the concentration of PM10 (80.3 ± 24.4 μg/m3), PM2.5 (45.1 ± 17.7 μg/m3), SO2 (7.86 ± 1.55 μg/m3), and NO2 (13 ± 1.81 μg/m3) was higher in southwest monsoon. Ozone (O3) and CO positively correlated with temperature and negatively correlated with relative humidity. The level of PM10, PM2.5, and CO concentrations exceeded the National Ambient Air Quality Standards (NAAQS) guidelines. The present study’s results emphasize the need of effective air pollution control in Coimbatore. Precautionary measures to be taken to avoid exposure of air pollutants to the public and minimize pollutants. This study further suggests an investigation on the adverse impact on human health and environment using appropriate risk analysis techniques.