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Traditional methods for the analysis of trace metals require particulate matter (PM) collected on specific filter substrates. In this paper, methods for elemental analysis of PM collected on substrates commonly used for organic analysis in air quality studies are developed. Polyurethane foam (PUF), polypropylene (PP), and quartz fiber (QF) substrates were first digested in a mixture of HNO(3)/HCl/HF/H(2)O(2) using a microwave digestion system and then analyzed for elements by inductively coupled plasma mass spectrometry. Filter blanks and recoveries for standard reference materials (SRMs) on these substrates were compared with a cellulose (CL) substrate, more commonly used for trace metal analysis in PM. The results show concentrations of filter blanks in the order of QF > PUF > PP > CL with a high variability in PUF and PP blanks relative to QF. Percent recovery of most elements from the SRMs on all substrates are within +/-20% of certified or reference values. QF substrates showed consistent blanks with a reproducibility better than +/-10% for the majority of elements. Therefore, QF substrates were applied to ambient PM collected in a variety of environments from pristine to polluted. Concentrations of field blanks for > or = 18 of 31 elements analyzed on a small section of QF substrate are < or = 25% of the amounts present in samples for urban atmospheres. Results suggest that QF used in a high-volume sampler can be a suitable substrate to quantify trace elements, in addition to organic species and hence reduce logistics and costs in air pollution studies.

As part of the Desert Southwest Coarse Particulate Matter Study which characterized the composition of fine and coarse particulate matter in Pinal County, AZ during 2010-2011, several source samples were collected from several different soil types to assist in source apportionment analysis of the study results. Soil types included native desert soils, agricultural soils (crop farming), dirt-road material adjacent to agricultural areas, paved road dusts, dirt road material from within and adjacent to a cattle feedlot, and material from an active cattle feedlot. Following laboratory resuspension of the soil, sizesegregated PM 2.5 and PM 10 fractions for each source type were collected on filters and characterized for mass, ions, OC, EC, and trace elements. While there are unique chemical compositions of soils in the region (e.g., high As and Sb) that reiterate the importance of using local source profiles (e.g., native soils) as compared to Upper Continental Crust or soil profiles from other regions in receptor modeling studies. The study also provides new insights into the impact of land-use modification on source emission profiles. Specifically, high OC and PO 4 3-are found in material representative of local cattle feedlot activities while elevated Cu, Sb and Zn are found from sources impacted by motor vehicle traffic. Results of the study indicate that the local native soil composition is only slightly modified by agricultural activities and this study provides the chemical composition of both native and agricultural soil for source apportionment studies in the Desert Southwest.

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