Characterization of PM10 over urban and rural sites of Rajnandgaon, central India

Abstract

The main aim of this study is to determine the water-soluble species of PM10 (particles having an aerodynamic diameter less than 10 μm) in urban and rural sites of Rajnandgaon district, central India, in 2009. The samples were collected on quartz fiber filters and analyzed for the major water-soluble ions Cl−, $${\text{NO}}_{3}^{ - }$$ , $${\text{SO}}_{4}^{{2 - }}$$ , $${\text{NH}}_{4}^{ + }$$ , Na+, K+, Mg2+ and Ca2+ parameters, employing ion chromatograph. These species show large spatial and temporal variations. On urban site, the ambient PM10 concentration has been observed to be the highest 167 ± 64 μg m−3 (winter) followed by 141 ± 65 μg m−3 (post-monsoon), 112 ± 53 μg m−3 (pre-monsoon) and lowest 34 ± 13 μg m−3 (high monsoon), whereas in rural background, the PM10 concentration was highest 153 ± 54 μg m−3 (winter) followed by 122 ± 53 μg m−3 (post-monsoon), 102 ± 39 μg m−3 (pre-monsoon) and lowest 32 ± 11 μg m−3 (high monsoon). The measured concentrations were excess of annual averages specified by the Indian National Ambient Air Quality Standards of PM10 60 μg m−3. Simultaneously, the measurement of organic carbon (OC) and elemental carbon (EC) was also taken. The annual concentration of OC and EC in urban site was found to be 5.9 and 4.8 μg m−3, but in the rural site, the concentration was 3.11 and 2.78 μg m−3 with OC/EC ratios 1.90 and 1.73 in urban and rural sites, respectively. Higher levels were obtained at urban site as compared to rural site. This suggested that the urban site exhibited a more serious climatic impact on the background air.