ASSESSING SOURCES OF AIRBORNE MINERAL DUSTS AND OTHER AEROSOLS, IN IRAQ

The purpose of the Enhanced Particulate Matter Surveillance Program (EPMSP) was to provide scientifically founded information on the chemical and physical properties of airborne mineral dust and other aerosols sampled in the Middle East. Analytical results are available on the Defense Occupational and Environmental Health Readiness System (DOEHRS), to assist in assessing potential health effects from exposure to ambient particulate matter, by inhalation, ingestion and dermal absorption. Aerosol and bulk soil samples were collected during a period of approximately one year during 2006, at 15 Middle East sites, including Djibouti (1), Afghanistan (2), Qatar (1), United Arab Emirates (1), Iraq (6), and Kuwait (4). Collocated low volume particulate samplers, one each for the total suspended (TSP), less than 10 mm in aerodynamic diameter (PM₁₀) and less than 2.5 mm in aerodynamic diameter (PM_2.5) particulates were deployed at each of the sites and operated on a “1 in 6 day” sampling schedule. The approximately 2,765 filters were chemically analyzed for their elemental and ion contents, for their elemental (EC) and organic carbon (OC) fractions, and individual particles by scanning electron microscopy (SEM). Laboratory results from the EPMSP include 66,462 analyses on Teflon^® membrane, 23,807 on quartz fiber, and several million single particle analyses on Nuclepore^® filters. Principal Components Analysis (PCA) and Positive Matrix Factorization (PMF) were applied to subsets of the chemical data, to better resolve the sources of air pollutants. This presentation reports on the PMF of chemical results from Teflon filters, to identify sources and assess contributions from different mineral dusts and anthropogec sources impacting along the Tigris and Euphrates river valleys. PMF modeled sources include siliceous, calcic and gypsum dusts, salt, as well as an anthropogenic source of lead (Pb) and antimony (Sb). The variations of sources impacting at each of the sampling sites are discussed. Independently of dust storms are the seasonly high levels of metals in aerosol samples collected at three sites along the Tigris River.