Analysis of seasonal and spatial distribution of particulate matters and gaseous pollutants around an open cast coal mining area of Odisha, India

Abstract

Open cast mining - a predominant method of coal production in India (94.46% of total coal production) - has been found to be a major factor which is responsible for the emission of dust particles and gaseous pollutants, leading to the deterioration of air quality in the coal mining area. Considering the health concerns and environmental impacts of these pollutants, the inhabited villages of Ib valley coalfield area of Orisha, India, were selected for this study. In this regard, various researchers have performed the analysis of air quality data and modeling for the dispersion of pollutants. However, a long-term study on spatial and seasonal variations of air pollutants and their relationship with meteorological parameters were missing in the literature. Accordingly, the spatial and seasonal variations of air pollutants in the area were assessed for a period of six years (2014 - 2020), and concentrations of PM_2.5, PM₁₀, and SPM were found to be above the annual national ambient air quality standards (NAAQS) for all the three seasons. The overall mean concentrations of NO_x, PM₁₀, PM_2.5, SPM, and SO₂ during this period were found to be 17.2 ± 9.28, 152.5 ± 99.7, 53.27 ± 37.70, 268.5 ± 158.2, and 12.58 ± 7.47 μg/m³, respectively. The analysis of meteorological parameters showed a strong and significant negative correlation of relative humidity with PM_2.5 (r = - 0.30, p-value = 5.659 × 10^-10), PM₁₀ (r = - 0.36, p-value = 1.97 × 10^-13), and SPM (r = - 0.45, p-value = 2.2 × 10^-16). Furthermore, the spatial distribution of pollutants was performed using the geographic information system (GIS) and inverse distance weighting (IDW) method, wherein the seasonal distribution of pollutants was shown through the bivariate polar plots. Therefore, the analyses and recommendations provided in this study can help the policymakers in developing a long-term air quality improvement strategy around a coal mining area, including the spatial and seasonal variations of air pollutants and their relationship with meteorological parameters.

Keywords: Air Quality Index (AQI); Bivariate polar plots; Correlation; Geographic Information System (GIS); Inverse distance weighting (IDW) method; Meteorological parameters; Open cast mining (OCM), Spatial dispersion.