Primary Pollutants and Potential Photochemical Smog Formation in Makkah, Saudi Arabia PDF

Keywords

Primary pollutants, O, NO, Photochemical smog, UV, Mina valley

Abstract

This study was conducted in Mina Valley and the central district of the holy city, Makkah. during the pilgrimage (Hajj) season of 1424 Hijri (2004). During this season, more than 25 million people gathered in Makkah and Mina Valley to perform the Hajj rituals. Two Mobile air pollution laboratories were used to monitor NO, NO2, NOX, non methane hydrocarbons and ozone (O3) in the atmosphere in Mina and Makkah Instruments were calibrated periodically against standard gases The present investigation showed clearly an ideal diurnal cycle of local ozone formation Although the intensity of the incoming UV radiation was the lowest compared with other months of the year, recorded ozone levels approached the maximum allowable levels of 150 micro g/m3 in Mina, and exceeded 160 micro g/m3 in Makkah during the pilgrimage period. The problem was intensified by the high recorded levels of NOx, sometimes reaching more than 800 micro g/m3, 1 h average, coupled with 1h average concentration of about 3 ppm non-methane hydrocarbons. Furthermore, the average maximum hourly ozone concentrations increased gradually from less than 60 micro g/m3 during February to reach more than 200 micro g/m3 (as an indication of smog formation) during some days of May. This coincides with the increase in the intensity of the incoming UV radiation reaching its maximum level in May. Consequently, it can be concluded that Makkah may face severe air pollution episodes when the pilgrimage season shifts to the summer months in the next few years. This may pose acute health problems for elderly people and those with respiratory health problems. Good air quality and transportation management as well as the use of alternative clean fuel are highly recommended.