Risk assessment of exposure to volatile organic compounds in the holy city of Makkah

Abstract

Millions of pilgrims arrive in Makkah every year to perform Hajj and/or Umrah. The increase of pilgrim numbers is accompanied by the increase of their daily activities as well as the increase in the demands of transportation means. Consequently, considerable quantities of either gaseous or solid pollutants are emitted to the atmosphere. The present study focuses on volatile organic compounds (VOCs) where there is a lack of studying VOCs as air toxins and it is considered as the first of its kind in Saudi Arabia. The goals of the current work aimed to: I) develop adequate air monitoring technology (methodology) for VOCs; II) assess the life time of cancer and non-cancer risk; and III) enhance research capacity on VOCs air pollution and health risk analysis. The ambient VOCs samples (during Hajj season 1431H) were collected from different sites (Al-Shbaikah, Al-Aziziah and Mina). Fourteen (14) VOCs compounds (benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, 1,2,4-trimethylbenzene, vinyl chloride, styrene, chlorotolune, 1,2- dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene and 1,2,3- trichlorobenzene) were targeted in this study. The mean concentrations of most abundant group of VOCs; Benzene, Toluene, Ethylbenzene, and Σ Xylene in El Shebaka were 8.11; 15.85; 9.20; 8.45 μg/m3, respectively during day time and 31.44; 37.80; 42.03 and 38.71 μg/m3 during night time, respectively. In Al- Aziziah, the values measured were 11.75; 9.42; 48.8; and 33.49 μg/m3 during day time, meanwhile, during night time were 4.78; 6.67; 8.45; and 18.56 μg/m3, respectively. The concentrations of benzene, toluene, ethylbenzene, xylenes in the air were significantly higher than other species. The lifetime cancer and noncancer risks for the population groups exposed to VOCs were also assessed in detail. Noncancer risk was estimated in relation to the reference hazard level of 1.0. It was found that benzene may be the most important cause of both cancer and noncancer risk. © 2012 WIT Press.