PHYSICO-CHEMICAL CHARACTERIZATION OF PM10 IN AMBIENT AIR OF ROORKEE

Abstract

The physico-chemical characterization of fine particles of size PM10 (particle matter with aerodynamic diameter < 10 vim) is of prime importance because of their severe health impacts on humans. The Physico-Chemical characterization of PM10 (e.g. S02-4, NO-3, NH4÷ and TOC) at five sites in Roorkee, a small town in Haridwar district of Uttarakhand state of India was carried out during January-May 2007. All these characteristics cause serious indirect effect on atmospheric chemistry, climate, human health and quality of life, For example, sulfate and nitrate contribute to change in incoming solar radiation and pH of rainwater (acid rain). Total organic carbon can influence the cloud condensation nucleation process. The instrument used for sampling was Respirable Dust Sampler and whatman's GF/A grade filter were used. The highest level of PM10 concentration was observed at civil line (132 μg/m3) in the month of January 2007. It could be due to enormous volume of traffic and frequent use of D.G sets during power supply disconnected. The highest level of PM10 concentration was observed in winter season (132 μg/m3). It could be due to a stable or inversion atmospheric lapse rate, resulting in little dispersion or dilution of pollutants, which, in its turn, helps in the build-up of pollution concentrations to higher levels. The pH, Conductivity (K) of water soluble matter of PM10 were determined, and the water soluble fraction of the sample was followed to identify the Total Organic Carbon (TOC), S02-4, NO-3, NH+4 . Also, levels of 7 heavy metals (Cr, Cu, Mn, Zn, Fe, Cd and Pb) were determined by using the atomic absorption spectroscopy (AAS). The experimental results show that pH of water soluble matter of PM10 varies from 5.6 to 7.1. Conductivity of water-soluble species of PM10 ranges from 209 ps/cm to 1087 Rs/cm. NPOC was found much more than S024 and NO-3 in the PM10. Nitrate (NO-3), Sulfate (S02-4) and Ammonical Nitrogen (NH+4) were also determined. The highest level of nitrate (5.69 mg/g) was observed in industrial area. The highest level of sulfate (6.42 mg/g) was also at Civil Line. The highest level of metal pollution concentrations were found that of Pb (157.12 mg/g of PM10), Zn (14.21 mg/g of PM10) and Fe (30.4 mg/g of PM10). These are mainly derived from industrial sources, combined with traffic sources. The high Zn content may come from traffic sources, especially vehicle tyres.