carbon analyses. The Desert Research Institute conducted x-ray diffraction (XRD), XRF, carbon, and ion analyses on 15 resuspended samples. R.J. Lee Group was responsible for individual particle analysis using computer-controlled scanning electron microscopy (CCSEM) and the secondary electron imaging by high magnification scanning electron microscopy (SEM).

A sampling schedule of 1 day in 6 was followed. Because of the limited availability of samplers and personnel to conduct the sampling, only one sample set (with Teflon filters, “Sample Set T”; with quartz-fiber filters, “Sample Set Q”; or with Nuclepore filters, Sample Set “N”) was collected on a given sampling day. During a period of 1 month, there were two sampling days each for Teflon and quartz-fiber filters, and one sampling day for Nuclepore filters. During the field campaign period, 40% of the samples were collected on Teflon filters, 40% on quartz-fiber filters, and 20% on Nuclepore filters. Thus, during the period of the sampling year, Teflon and quartz-fiber filters each were collected for a maximum of 7% of the days. The sampling time for Teflon and quartz-fiber filters was 24 hours. For the Nuclepore filters, the sampling period was only 2 hours because CCSEM analysis requires that filter samples be only lightly loaded.