Nitrogen oxides and photochemical oxidants in Cairo City atmosphere

Concentrations of nitrogen oxides were measured continuously for a period of 12 months in the city of Cairo. Photochemical oxidants were examined and their appearance was found to be highly dependent on the NO_x diurnal cycle and wind speed. Nitrogen oxides were found to exceed 10 times the USA air quality standard. Oxidants concentrations were found to exceed 0.1 ppm, average over 1 h, on 74% of the measured days.