Document Details

Document Type : Article In Journal 
Document Title :
Diurnal, seasonal and weekdays–weekends variations of ground level ozone concentrations in an urban area in greater Cairo
الاختلافات اليومية والموسمية وكذلك أثناء أيام العمل وعطلات نهاية الأسبوع فى مستويات تركيزات غاز الأوزون السطحى فى منطقة حضرية بالقاهرة الكبرى
Document Language : English 
Abstract : Ground level ozone (O3) concentration was monitored during the period of December 2004 to November 2005 in an urban area in Greater Cairo (Haram, Giza). During the winter and summer seasons, nitrogen dioxide (NO2) and nitric oxide (NO) concentrations and meteorological parameters were also measured. The mean values of O3 were 43.89, 65.30, 91.30 and 58.10 ppb in daytime and 29.69, 47.80, 64.00 and 42.70 ppb in whole day (daily) during the winter, spring, summer and autumn seasons, respectively. The diurnal cycles of O3 concentrations during the four seasons revealed a uni-modal peak in the mid-day time, with highest O3 levels in summer due to the local photochemical production. The diurnal variations in NO and NO2 concentrations during the winter and summer showed two daily peaks linked to traffic density. The highest levels of NOx were found in winter. Nearly, 75%, 100%, 34.78% and 52.63% of the mean daytime concentrations of O3 during spring, summer, autumn and the whole year, respectively, exceeded the Egyptian and European Union air quality standards (60 ppb) for daytime (8-h) O3 concentration. About, 41.14% and 10.39% of the daytime hours concentrations and 14.93% and 3.77% of the daily hour concentrations in summer and the whole year, respectively, exceeded the Egyptian standard (100 ppb) for maximum hourly O3 concentration, and photochemical smog is formed in the study area (Haram) during a periods represented by the same percentages. This was based on the fact that photochemical smog usually occurs when O3 concentration exceeds 100 ppb. The concentrations of O3 precursors (NO and NO2) in weekends were lower than those found in weekdays, whereas the O3 levels during the weekends were high compared with weekdays. This finding phenomenon is known as the “weekend effect”. Significant positive correlation coefficients were found between O3 and temperature in both seasons and between O3 and relative humidity in summer season, indicating that high temperature and high relative humidity besides the intense solar radiation (in summer) are responsible for the formation of high O3 concentrations. 
ISSN : 1-008-0208-7 
Journal Name : Environmental Monitoring and Assessment 
Volume : 149 
Issue Number : 0 
Publishing Year : 1430 AH
2009 AD
Article Type : Article 
Added Date : Monday, August 22, 2011 


Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
ممدوح إبراهيم خضيرKhoder, Mamdouh


File NameTypeDescription
 30326.pdf pdfDiurnal, seasonal and weekdays–weekends variations

Back To Researches Page