Assessment and management of air quality for an opencast coal mining area

Abstract

A study for the assessment and management of the air quality was carried out at Lakhanpur area of Ib Valley Coalfield in Orissa state in India. The 24-h average concentrations of total suspended particulate (TSP) matter, respirable particulate matter (PM 10), sulphur dioxide (SO 2) and oxides of nitrogen (NO x ) were monitored during 1 year period. Samplings were done at a regular interval through out the year at 13 monitoring stations in the residential areas and four monitoring stations in the mining/industrial areas. The 24-hr average TSP and PM 10 concentrations ranged from 338.8 to 799.8 μg m −3 and 102.5–425.6 μg m −3 for industrial area, and 72.3–497.1 μg m −3 and 40.8−171.9 μg m −3 for residential area, respectively. During the study period 24-hr and annual average TSP and PM 10 concentrations exceeded the respective standards set in the national ambient air quality standard (NAAQS) protocol at most residential and industrial areas. However, 24-hr and annual average concentrations of SO 2 and NO x were well within the prescribed limit of NAAQS both in the residential and industrial areas. The annual and 24-hr average concentrations varied from 23.3 to 36.8 μg m −3 and 16.0–55.2 μg m −3 for SO 2 and 23.9−41.9 μg m −3 and 19.0–58.1 μg m −3 for NO x , respectively. The temporal variations of TSP and PM 10 fitted polynomial trend with an average correlation coefficient ( R 2) of 0.77 (±0.17) for TSP and 0.85 (±0.10) for PM 10. On average the PM 10 in the ambient air of the mining area constituted 31.94 (±1.76)% of the TSP. The linear regression correlation coefficient ( R 2) between TSP with PM 10 and NO x with SO 2 was 0.86 (±0.12) and 0.57 (±0.20), respectively. Maximal concentrations of TSP and PM 10 occurred within the mining site based on the kriging technique. A management strategy is formulated for effective control of air pollution at source and other mitigative measures recommended including implementation of green belts around the sensitive areas where the concentration of air pollutants exceeded the standard limit.