Particulate Matter Assessment Using In Situ Observations from 2009 to 2014 over an Industrial Region of Eastern India

Abstract

The present study discusses the ambient air quality of an East Indian industrial region. The 8 hourly average concentrations of suspended particulate matter (SPM) and respirable suspended particulate matter (RSPM) for the period January 2009–December 2014 was analyzed at two industrial sites: Rourkela Township and Rajgangpur; and a residential site in the vicinity of industrial sites, i.e., Sonaparbat situated in Sundergarh District of Orissa State, India. The study area holds one of the biggest steel plants in India, cement factory and many medium- and small-scale industries in its surrounding area. To understand the contribution of the fine mode (PM2.5—also called RSPM) and inhalable coarse particles (PM10—also called SPM) to the particulate matter pollution, the ratio of PM2.5/PM10 is considered over the industrial and residential sites. Sonaparbat is loaded with more PM10 (particles concentration > 250 µg/m3) and dominance of PM2.5 was noticed during the years 2013 and 2014 compared to Rourkela and Rajgangpur. To detect the presence of specific emission sources that enhance the pollution over receptor sites, the conditional probability function and conditional bivariate probability function techniques are employed in the present study. Concentration weighted trajectory analysis using the 2-day back trajectory (by HYSPLIT-4 model) is also employed in the present study to discover the impact of transboundary pollution. Calm and weak wind speeds (< 1.5 ms−1) are noticed over the study area, thereby indicating the pollution due to local sources present in and around the city. Rourkela Steel Plant, Orissa Cements Limited (OCL), OCL Iron and Steel along with vehicular exhaust are some of the major local sources situated within the vicinity of 5 km in the study area. The results show that pollution levels have a significant contribution from adjacent industrial areas apart from local emission sources, especially in the northwesterly and southeasterly directions. Further, an attempt has been made to investigate the dispersion of pollutants from the study site to the nearby regions during the study period by employing the 48-h seasonal forward trajectory analysis using the HYSPLIT-4 model.