Study on surface ozone and its precursors at an urban site of Delhi, India

Abstract

Continuous measurements of the surface ozone (O₃), oxidess of nitrogen (NO_x), carbon monooxide (CO), methane (CH₄) and total non-methane hydrocarbons (TNMHCs) have been carried out at an urban site of Delhi, India during 1–31, May 2014 to study the influence of ozone precursors (NO_x, CO, CH₄ and TNMHCs) in the formation of surface O₃ over Delhi. In the present study, the average mixing ratios of surface O₃, NO, NO₂, CO, CH₄ and NMHCs were recorded as 37.1 ± 9.8 ppb, 20.4 ± 13.1 ppb, 14.7 ± 3.2 ppb, 1.4 ± 0.5 ppm, 2.6 ± 0.4 ppm and 0.13 ± 0.09 ppm, respectively. The surface O₃, NO, NO2, CO, CH₄ and TNMHCshave shown the prominent diurnal variations during study. The result reveals that the surface O₃ positively correlated with NO₂, TNMHCs, NO₂/NO and NMHCs/NO_x and influenced the surface O₃ production at the observational site of Delhi.