Influence of Temperature, Relative Humidity and Seasonal Variability on Ambient Air Quality in a Coastal Urban Area

[摘要] 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. This study analyses the influence of temperature and relative humidity on ambient SO2, NOx, 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 results of the study show that both SO2and NOxwere negatively correlated in summer (r2=0.25for SO2andr2=0.15for NOx) and moderately and positively correlated (r2=0.32for SO2andr2=0.51for NOx) during post-monsoon season with temperature. RSPM and SPM had positive correlation with temperature in all the seasons except post-monsoon one. These findings indicate that the influence of temperature on gaseous pollutant (SO2& NOx) is much more effective in summer than other seasons, due to higher temperature range, but in case of particulate, the correlation was found contradictory. 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. Statistically significant negative correlations were found between humidity and particulates (RSPMand SPM) in all the four seasons, but level of correlation was found moderate only during monsoon (r2=0.51andr2=0.41) in comparison with other three seasons and no significant correlation was found between humidity and SO2, NOxin all the seasons.It is suggested from this study that the influence of humidity is effective on subsidingparticulates in the coastal region.

[学科分类] 地质学