Measurements of O₃ and NO₂ levels at a suburban site in Agra

Abstract

The O₃ and NO₂ levels were measured at Dayalbagh Educational Institute, Dayalbagh (Agra), a suburban site locate in a semi-arid tract of north central India. The mean concentrations of O₃ and NO₃ for the entire data set (<i>N</i>=182) were 20.1±18.6 ppb and 21.2±16.7 ppb, respectively. Ozone showed a significant positive correlation (<i>r</i>=0.45) wit temperature and negative correlation with RH (<i>r</i>= -0.64). The NO₂ level was inversely related to temperature (<i>r</i>= -0.42) and positively correlated with RH (<i>r</i>=0.30). Diurnal variations were obtained for both O₃ and NO₂. Maximum O₃ concentration was observed in the afternoon in winter (33.7 ppbv) and NO₂ showed two peaks-one at about 0800 hrs LT (31.0 ppb) and the other at about 1800 hrs LT (27.0 ppb) corresponding to traffic rush hours. The O₃ and NO₂ values were higher in the winter months.