title: Inhalable desert dust, urban emissions, and potentially biotoxic metals in urban Saharan-Sahelian air.
abstract: Saharan dust incursions and particulates emitted from human activities degrade air quality throughout West Africa, especially in the rapidly expanding urban centers in the region. Particulate matter (PM) that can be inhaled is strongly associated with increased incidence of and mortality from cardiovascular and respiratory diseases and cancer. Air samples collected in the capital of a Saharan-Sahelian country (Bamako, Mali) between September 2012 and July 2013 were found to contain inhalable PM concentrations that exceeded World Health Organization (WHO) and US Environmental Protection Agency (USEPA) PM2.5 and PM10 24-h limits 58 - 98% of days and European Union (EU) PM10 24-h limit 98% of days. Mean concentrations were 1.2-to-4.5 fold greater than existing limits. Inhalable PM was enriched in transition metals, known to produce reactive oxygen species and initiate the inflammatory response, and other potentially bioactive and biotoxic metals/metalloids. Eroded mineral dust composed the bulk of inhalable PM, whereas most enriched metals/metalloids were likely emitted from oil combustion, biomass burning, refuse incineration, vehicle traffic, and mining activities. Human exposure to inhalable PM and associated metals/metalloids over 24-h was estimated. The findings indicate that inhalable PM in the Sahara-Sahel region may present a threat to human health, especially in urban areas with greater inhalable PM and transition metal exposure.
authors.affiliation: US Geological Survey, 600 4th Street South, St. Petersburg, FL 33701, USA. Electronic address: ginger_garrison@usgs.gov.
authors.forename: V H
authors.initials: VH
authors.lastname: Garrison
authors.affiliation: US Geological Survey, 6000 J St., Sacramento, CA 95819-6129, USA. Electronic address: majewski@usgs.gov.
authors.forename: M S
authors.initials: MS
authors.lastname: Majewski
authors.affiliation: US Embassy, Bamako, Mali. Electronic address: lacikonde.lk@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Konde
authors.affiliation: US Geological Survey, Denver Federal Center, Lakewood, CO 80225-0046, USA. Electronic address: rwolf@usgs.gov.
authors.forename: R E
authors.initials: RE
authors.lastname: Wolf
authors.affiliation: US Department of State, Office of Medical Services, 2401 E. Street NW, Washington, DC 20522-0101, USA. Electronic address: ottord@state.gov.
authors.forename: R D
authors.initials: RD
authors.lastname: Otto
authors.affiliation: Embassy of Japan in Sri Lanka, No. 20 Gregory's Road, Colombo 7, Sri Lanka. Electronic address: yutaka.tsuneoka@mofa.go.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuneoka
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D003889:Desert Climate; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring; D019570:Inhalation Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D008670:Metals / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis
chemical_list: D000393:Air Pollutants; D004391:Dust; D008670:Metals; D052638:Particulate Matter
keywords: Elemental composition; Human health; PM(10); PM(2.5); Sahara–Sahel; Transition elements