Urban area
Īir pollutants are being let out into the atmosphere from a variety of sources, and the concentration of pollutants in the ambient air depends not only on the quantities that are emitted but also the ability of the atmosphere, either to absorb or disperse these pollutants. Prior to 1981, there were no specific standards for Ambient Air Quality (AAQ) in India, and after enforcement of Air (Prevention and Control of Pollution) Act 1981, the first Ambient Air Quality standards were adopted in November 1982 and revised in April 1994 and again in November 2009. Even before epidemiological studies confirmed the existence of association between air pollution and human health, laws have been proposed to control the burning of fuels in London. Industrial revolution started 200 years ago, and its consequences to human beings were recognized at the middle of 20th century. It is suggested from this study that the influence of humidity is effective on subsiding particulates in the coastal region. Statistically significant negative correlations were found between humidity and particulates (RSPM and SPM) in all the four seasons, but level of correlation was found moderate only during monsoon ( and ) in comparison with other three seasons and no significant correlation was found between humidity and SO 2, NO x in all the seasons. The very weak to moderate correlations existing between the temperature and ambient pollutant concentration during all seasons indicate the influence of inconstant thermal variation in the coastal region. These findings indicate that the influence of temperature on gaseous pollutant (SO 2 & NO x) is much more effective in summer than other seasons, due to higher temperature range, but in case of particulate, the correlation was found contradictory. RSPM and SPM had positive correlation with temperature in all the seasons except post-monsoon one. The results of the study show that both SO 2 and NO x were negatively correlated in summer ( for SO 2 andįor NO x) and moderately and positively correlated (įor SO 2 and for NO x) during post-monsoon season with temperature. This study analyses the influence of temperature and relative humidity on ambient SO 2, NO x, RSPM, and SPM concentrations at North Chennai, a coastal city in India, during monsoon, post-monsoon, summer, and pre-monsoon seasons for 2010-11 using regression analysis. The concentration of air pollutants in ambient air is governed by the meteorological parameters such as atmospheric wind speed, wind direction, relative humidity, and temperature.