Photochemical Transformation and Ambient Ozone in the City of Jeddah

High level of tropospheric ozone (o3) in the air is toxic to living organisms. it is formed due to photolysis reaction of nitrogen oxides in the presence of non-methane hydrocarbons and other organics, and is mainly associated with the emissions from automobiles in urban areas. with the increased urbanization across the kingdom of saudi arabia, a better understanding on the precursors and origin of ozone formation is critical for its control. in this paper, hourly measured data on ozone levels in jeddah city, which is located on the west coast of saudi arabia, were presented. the hourly data from 1999 to 2003 were obtained from the presidency of meteorology and environment (pme) air quality monitoring network (aqmn) database. the analysis shows the highest concentration of ozone during the late morning and afternoon periods. high o3 levels were found in the northern and southern parts of jeddah city along the red sea coast; and low concentration at the industrial estate in the southern part of the city.