SEASONAL VARIATIONS OF AMBIENT AIR QUALITY PARAMETERS OF SOME SELECTED SITES OF ASANSOL SUBDIVISION UNDER ASANSOL DURGAPUR DEVELOPMENT AUTHORITY (ADDA), WEST BENGAL, INDIA

摘要

Present study has been made to measure the status of ambient air quality and impacts of air pollutants on the surrounding regions of Asansol sub-division of Asansol Durgapur Development Authority (ADDA), West Bengal, India. Ambient air quality status was evaluated to monitor with respect to Respirable suspended Particulate Matter (RSPM<10μ), Suspended Particulate Matter (SPM), SO_2, NO_2, and Carbon monoxide (CO) during two consecutive years (2014 and 2015). Six selected sites, two in each of three referring sites, namely control or non-industrial, semi-industrial, and industrial were considered for monitoring in three seasons (i.e., winter, summer, and monsoon). Sampling was done for 24 hr for RSPM (<10μ), SPM, SO_2, NO_2, and 1 hr for carbon monoxide (CO). Meteorological parameters such as air temperature, relative humidity, barometric pressure, smell or odour and weather conditions were also taken into consideration. RSPM in 2014 was higher in winter concentration (155.3±78.6 μg/m~3) in comparison to summer (138.1±75.1 μg/m~3) and rainy (120.3±62.9 μg/m~3); and in 2015, the average values of RSPM were 130.5±60.8 μg/m~3 in winter, 115.0±56 μg/m~3 in summer and 95.6±50.2 μg/m~3 in rainy season. In 2014, SPM values were 702.4 μg/m~3, 687.6 μg/m~3 and 610.8 μg/m~3 as maximum concentration in winter, summer and rainy season respectively; and maximum concentration of SPM was recorded in winter, summer and rainy seasons (605.1 μg/m~3, 578.3 μg/m~3, 452.1 μg/m~3 respectively) in 2015. During winter, summer, and rainy, the value of SO_2 were 9.79±1.341 μg/m~3, 9.112±1.475 μg/m~3, and 8.772±1.31 μg/m~3 respectively in 2014; and 10.215±2.313 μg/m~3, 9.257+1.883 μg/m~3, and 8.965±1.426 μg/m~3 respectively in 2015. The average concentration of NO_2 in the study area for winter, summer and rainy were 42.06±6.93 μg/m~3, 37.77±3.84 μg/m~3 and 33.98±6.24 μg/m~3 respectively in 2014; whereas, in 2015, there were 40.06±2.78 μg/m~3, 37.96±3.74 μg/m~3 and 36.96±3.7 μg/m~3 respectively. During winter season, the mean concentrations of carbon monoxide in 2014 and 2015 were recorded as 1.043±0.511 mg/m~3, and 0.976±0.571 mg/m~3 respectively. From these results it can be concluded that there were a sharp seasonal variations among the air pollutants and the impacts were more significant, due to high concentration in winter compared to other seasons of study.