Determination and Comparison of the Elemental Composition of Air Particulates With Aerodynamical Diameters of 10 and 2.5 Microns in El Paso-Juarez AirshedEPA Grant Number: U915914
Title: Determination and Comparison of the Elemental Composition of Air Particulates With Aerodynamical Diameters of 10 and 2.5 Microns in El Paso-Juarez Airshed
Investigators: Espino, Tania T.
Institution: The University of Texas at El Paso
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2001 through January 1, 2004
Project Amount: $105,997
RFA: Minority Academic Institutions (MAI) Fellowships for Graduate Environmental Study (2001) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Academic Fellowships , Fellowship - Environmental Science
The objective of this research project is to determine and compare the elemental composition of air particulates with aerodynamical diameters of 10 and 2.5 microns in the El Paso-Juarez Airshed.
Air quality may be the most fundamental environmental challenge in large urban areas along the United States-Mexico border. Air crosses this border freely in both directions at the whim of the wind, and every resident must share this resource. In the El Paso-Juarez Airshed, lack of rain and vegetation, a windy climate, extensive unpaved urban areas, an aged vehicle fleet, and industrial emissions coalesce to make particulate matter (PM) in our air a serious environmental problem. Despite this, our understanding of the composition, toxicity, and origin of particulates is limited. Such knowledge is a prerequisite for evaluation of the hazards of particulates and the formulation of remediation or amelioration strategies. Low wind speeds would produce sampling conditions that reflect local production of particulates, a consideration in source apportionment of metals. Among the available filters, we will select days with average wind speeds between 0 and 15 km/hour (the lowest possible). We will obtain the appropriate PM10 quartz-fiber high-volume filter samples from the archived collection of the El Paso City-County Health and Environmental District. These 24-hour samples were taken from four sites in El Paso, TX, and five in Ciudad Juarez, Chihuahua, Mexico. These sites had been selected previously using siting criteria under the 1987 PM10 regulation. PM with aerodynamic diameters of 2.5 and less will be compared in their elemental composition. Teflon filters were sampled in El Paso-Juarez region during the fall, winter, or spring of 1999, 2000, and 2001. PM2.5 filters metal analyses will be compared to the PM10 to see the differences in their behavior during the various seasons of the year. The PM2.5 fraction of PM will be interesting to understand, because the PM2.5 particles may have the potential to affect health.
The filters will be subsampled, and for microwave extraction, we will follow the protocols of the U.S. Environmental Protection Agency (EPA) Method 3051 Microwave Assisted Acid Digestion of Sediments, Sludges, Soils and Oils (U.S. Environmental Protection Agency, 1994). Extractions will be performed in a CEM MDS-2000 microwave unit with sealed Teflon reaction vessels. Inductively coupled plasma mass spectrometry (ICP/MS) analysis will be performed on the filter after extraction using a Hewlett Packard HP 4500 instrument. We will follow appropriate protocols in two EPA methods: Determination of Trace Elements in Waters and Wastes by ICP/MS and Determination of Metals in Ambient Particulate Matter Using ICP/MS. The first of these is Method 200.8, and the second is a preliminary draft Method, EPA/625/R-96/010a (EPA, 1991; 1997). Samples will be analyzed for 65 elements, of which, approximately 30 elements typically were found consistently at quantifiable levels.