Characteristics of air pollutants at near and far field regions of a national highway located at an industrial complex

Abstract

This paper presents the characterization of air quality monitored at near field region (NFR) and far field region (FFR) of a national highway located at an industrial complex. The pollutants such as PM10, SO2 and NO2 were monitored in two campaigns (11th September to 18th October 2012 and 18th January to 17th February 2013). The 24h average PM10 concentration at NFR and FFR were found to be 86.69±18.56μg/m3; 73.16±16.21μg/m3 and 89.44±18.69μg/m3; 81.91±16.42μg/m3, respectively during first and second campaign. In both the campaigns PM10, SO2 and NO2 concentration at NFR was higher than FFR. The chemical characterization of PM10 at NFR and FFR indicated the abundance of major elements such as Na (NFR=30% and FFR=32%), Ca (NFR=12% and FFR=14%) and ions namely NO3− (NFR=71% and FFR=68%) and NH3+ (NFR=15% and FFR=19%). Further, at FFR, SO42− and NO3− were found to be 18% and 35% higher than NFR indicating the conversions of SO2 and NO2 concentration into secondary particles. The measured SO2 and NO2 concentrations were 23 and 21% lower at FFR when compared to NFR confirms the secondary formation.The CALPUFF, EPA regulatory model was set up to understand the dynamics of air pollutants at the industrial complex. The predicted PM10, SO2 and NO2 concentrations at NFR and FFR were found to be 32.31±1.56μg/m3 and 31.35±1.27μg/m3; 0.37±0.21μg/m3 and 0.06±0.04μg/m3; 12.83±6.55μg/m3 and 4.67±2.77μg/m3, respectively. The model showed moderate predictions for PM10 (R2=0.44–0.52), SO2 (R2=0.41–0.51) and NO2 (R2=0.45–0.61) concentrations.