title: Air quality in Mecca and surrounding holy places in Saudi Arabia during Hajj: initial survey.
abstract: The Arabian Peninsula experiences severe air pollution, the extent and sources of which are poorly documented. Each year in Saudi Arabia this situation is intensified during Hajj, the Holy Pilgrimage of Islam that draws millions of pilgrims to Mecca. An initial study of air quality in Mecca and surrounding holy sites during the 2012 Hajj (October 24-27) revealed strongly elevated levels of the combustion tracer carbon monoxide (CO, up to 57 ppmv) and volatile organic compounds (VOCs) along the pilgrimage route-especially in the tunnels of Mecca-that are a concern for human health. The most abundant VOC was the gasoline evaporation tracer i-pentane, which exceeded 1200 ppbv in the tunnels. Even though VOC concentrations were generally lower during a follow-up non-Hajj sampling period (April 2013), many were still comparable to other large cities suffering from poor air quality. Major VOC sources during the 2012 Hajj study included vehicular exhaust, gasoline evaporation, liquefied petroleum gas, and air conditioners. Of the measured compounds, reactive alkenes and CO showed the strongest potential to form ground-level ozone. Because the number of pilgrims is expected to increase in the future, we present emission reduction strategies to target both combustive and evaporative fossil fuel sources.
authors.affiliation: Department of Chemistry, University of California at Irvine (UC Irvine) , Irvine, California 92697, United States.
authors.forename: Isobel J
authors.initials: IJ
authors.lastname: Simpson
authors.forename: Omar S
authors.initials: OS
authors.lastname: Aburizaiza
authors.forename: Azhar
authors.initials: A
authors.lastname: Siddique
authors.forename: Barbara
authors.initials: B
authors.lastname: Barletta
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Blake
authors.forename: Aaron
authors.initials: A
authors.lastname: Gartner
authors.forename: Haider
authors.initials: H
authors.lastname: Khwaja
authors.forename: Simone
authors.initials: S
authors.lastname: Meinardi
authors.forename: Jahan
authors.initials: J
authors.lastname: Zeb
authors.forename: Donald R
authors.initials: DR
authors.lastname: Blake
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000473:Alkanes / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis*; D002248:Carbon Monoxide / Q000032:analysis*; D004784:Environmental Monitoring; D005579:Fossil Fuels; D010126:Ozone / Q000737:chemistry; D012529:Saudi Arabia; D001335:Vehicle Emissions; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D000473:Alkanes; D005579:Fossil Fuels; D001335:Vehicle Emissions; D055549:Volatile Organic Compounds; D002245:Carbon Dioxide; D010126:Ozone; D002248:Carbon Monoxide