التوزيع الزماني والمكاني لعنصر الأوزن الجوي وارتباطه بأكاسيد النيتروجين في الهواء الجوي لمدينة جدة

Abstract

Concentrations of ambient Ozone (O3) nitrogen oxides (NOx) were measured continuously for a period of 12 months in the city of Jeddah from December 2011 to December 2012. Meteorological parameters, wind speed, temperature, and relative humidity were monitored as well. Concentrations of ground O3 were found to be highly dependent on the NOx diurnal cycle and wind speed. Nitrogen oxides were found to exceed air quality standard especially in industrial site, while O3 concentrations were found to exceed 40 ppb, average over 1 h, on more than 24% of the measured days in the rural sites, while they were exceeded 30% in all other areas. O3 and NOx were inversely related; the highest average NOx concentration (96 ppb) occurred in rural area downwind of a desalination factory while average O3 concentrations peaked in the rural area upwind of a desalination factory up to 63.5 ppb and 72.6 in another rural area which we considered as background in the present study. The seasonal variations of O3 were more distinct than NOx. To the best of our knowledge, this is the first report providing comprehensive background information for air quality in an arid area in the developing world.