| Abstract |
A source apportionment study was conducted between March 18 and April 4, 1988, at Pleasant Valley, Nevada, to evaluate air pollutant concentrations to which community residents were exposed and the source contributions to those pollutants. Daily PM10 samples were taken for chemical speciation of 40 trace elements, ions, and organic and elemental carbon. Hourly hydrogen sulfide, wind speed and defection , sigma theta, temperature, and relative humidity data were also collected. The objectives of this case study are: (1) to determine the emissions source composition of the potential upwind source, a geothermal plant; (2) to measure the ambient particulate concentration and its chemical characteristics in Pleasant Valley; and (3) to estimate the contributions of different emissions sources to PM10., Source emissions from the power plant cooling tower and geological material around the source an receptor sites were sampled and chemically analyzed. Chemical mass balance receptor modeling was performed to determine the contribution of the power plant plume and other sources in the area to PM10 concentrations. The study found that: (1) particulate emissions from geothermal cooling tower plume consisted primarily of sulfate, ammonic, chloride, and trace elements; (2) no significant quantities of toxic inorganic species were found in the ambient air; (3) ambient PM10 concentrations in Pleasant Valley were within Federal standards; and (4) source contributions to PM10 were approximately 60% geological material; 20% motor vehicle exhaust; and 10% cooling tower plume. The PM10 levels, the chemical concentrations, and the sum source contribution estimates are much lower than those levels found to be deleterious to public health. |