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' Human Health Screening Evaluation <br /> Surland Homes—Bridle Creek February 12,2009 <br /> ' • Fluoranthene <br /> • Phenanthrene <br /> • Pyrene <br /> 5.4.2 Air Concentrations of Volatile Organic Compounds from Soil <br /> The estimated air concentration of VOCs volatilized from on-site soils into ambient air was used <br /> to estimate inhalation exposures, and subsequently inhalation hazards and risks from those <br /> chemicals. The concentration of VOCs in ambient air from soils was calculated using the <br /> following equation (PEA Guidance Manual, Figure 2.7): <br /> Ca =Ei 199 <br /> Where: <br /> Ca= ambient air concentration, mg/m3 <br /> Ei = total emission rate for compound i (mg/second) <br /> Air concentrations of the following volatile chemicals (PEA Guidance Manual) were estimated <br /> using this equation (Table 21): <br /> • Toluene <br /> • Ethylbenzene <br /> • Xylene(s) <br /> • Acenaphthene <br /> • Anthracene <br /> ' • Fluorene <br /> • Naphthalene <br /> ' Emission Rate for Volatile Organic Compounds <br /> The emission rates from soils to ambient air for VOCs (Table 22) were calculated using the <br /> 1 following equation (PEA Guidance Manual, Figure 2.6): <br /> 1-6 x 105 x Di x He x Co <br /> ' +� <br /> E, _ 0_ . Z3 K d <br /> O <br /> Dix <br /> 4. 84 + 0.046 x Kd <br /> ' He <br /> Where: <br /> Ei = average emission rate of contaminant i over the residential lot during the exposure <br /> interval, mg/sec <br /> Di = diffusivity in air for compound i, cm2/sec <br /> He = Henry's Law constant, atm-m3/mole <br /> ' Kd= soil-water partition coefficient, cm 3/g <br /> 10 <br /> From Science to Solutions <br />