SEASONAL VARIATION IN AIRQUALITY WITH RESPECT TO METALS, SPM, SO2 AND NOx

Abstract

Air quality analysis is done to predict the present condition of the atmosphere, to identify specific sources of air pollution and to control and assess the pollution. Major source of air pollution includes combustion in gasoline and diesel engines, wood combustion and bio-mass utilization, industrial emissions and natural sources. Vehicular emissions include nitrogen oxides (NOR), carbon monoxide (CO), volatile organic compounds (VOC), and particulate matter (PM). These emissions give rise to a range of air quality problems and human health concerns. VOC and NOR emissions play a central role in the formation of tropospheric ozone. In addition to primary PM that is emitted directly, engine exhaust contributes through gas-to-particle conversion processes to secondary particle formation. Particulate matters are known for their adverse impacts on human health, buildings and agriculture. Also, tropospheric ozone, particulate matter, and carbon dioxide have all been identified as important contributors to climate change. Exposure to Air pollutants imparts a wide range of acute and chronic health effects from minor physiological disturbances to deaths from respiratory and cardiovascular diseases. It may cause mild to severe cough, chest pain, bronchitis, congestion and phlegm, and cause or aggravate allergies. Respirable suspended particulate matters (RSPM or PM10 i.e. suspended particles with less then 10 microns in aerodynamic diameter) aggravate the diseases in the patients suffering from bronchitis, asthma, cardiovascular problems and influenza. It also adversely affects plants growth and decrease visibility. Finer particles (less then 2.5 micron diameters i.e. PM2.5) reach lungs and may result in toxicity causing chronic respiratory symptoms or impair pulmonary function. Air quality sampling and analysis are necessary to learn about the ambient concentrations of air pollutants and whether the concentration(s) of pollutant(s) violates the recommended air quality standards. In this report, ambient concentrations of SPM, NOR, SO2 and some trace metals were measured from October 2005 to May 2006 at a sampling station located nearby Delhi-Haridwar Highway (NH-58), SQCC gate of IIT Roorkee. The main aim of this study is to analyze how the air quality is changing from season to season and day time to night time. The data consists of 8hr average SPM, NOx and Metals as well as 1 hr average of SO2 concentrations. The measurements have been performed once a week (alternative day-night samples) during the study period. The annual average concentrations of SPM, NOx and SO2 were observed to be 414.4411g/m3, 68.37n/m3 and 27.79p.g/m3 respectively. In general, the maximum NOx, SO2 and metal values occurred during the winter season and the maximum values of SPM have been observed during the winter season as well as summer season also. Factor analysis has been conducted to divide the pollutants as source wise. According to the factor analysis SO2 and NOx has the maximum correlation and SPM has the maximum correlation with metals. A case study has been conducted during Diwali festival to predict the increased pollution level due to firing of crackers. According to the obtained results the concentration level of pollutants has been increased significantly on the festival day and decreased gradually from the day after the festival. 11