Seasonal Variability of Trace Gases (O3, NO, NO2 and CO) and Particulate Matters (PM10 and PM2.5) over Delhi

Abstract

Continuous measurements of particulate matters (PM2.5 and PM10) and trace gases (O3, NO, NO2 and CO) have been carried out at 8 different sites over Delhi to evaluate the ambient air quality of city during October 2010 to March 2013. The annual average mixing ratios of ambient O3, NO, NO2 and CO were recorded as 23.8 ± 10.9 ppb, 27.0 ± 18.0 ppb, 16.3 ± 6.8 ppb, and 1.62 ± 0.69 ppm respectively. The seasonal variation of these trace gases (O3, NO, NO2 and CO) are pominent with different amplitudes at these sites of Delhi. The linear correlation of surface O3 with NO, NO2, and CO suggests that the precursor gases have influenced the magnitude of O3. The annual average concentrations of PM2.5 and PM10 over Delhi are recorded as 146.0 ± 72.6 μg m-3 and 245.7 ± 112.1 μg m-3 respectively, which exceed the values of the national ambient air quality standards.