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of Environmental Health Assessment ("OEHHA") published a chronic reference exposure level of 3 µg/m3 for crystalline silica in February 2005.71 The unit risk factor for crystalline silica ranges from 0.45 to 2.9x104 (ug/m3)-1. (CAPCOA 10/93,72 Table 111-7.) B-57 The Project will generate large amounts of fugitive dust that contain cont crystalline silica. The Draft EIR did not estimate crystalline silica emissions from the Project and generally does not include the type of information required to estimate ` these emissions. The Applicant should be required to measure crystalline silica in core samples collected from its deposits and the Draft EIR should be revised to analyze the public health risks from these emissions. VII.B Meteorological Data Are Inadequate and Result in Underestimate of Impacts The public health impact analysis used air dispersion modeling to estimate L ambient concentrations of toxic air contaminants. This modeling relied on five years of meteorological data from the Fresno Airport. These airport data, collected at a location about 112 miles from the Project site, are neither site-specific nor is the quality of this data set acceptable for air dispersion modeling. The public health risk assessment which relies on these data for air modeling is therefore flawed and likely B-5B ` underestimates modeled concentrations and thus health risk, as discussed below. For air dispersion modeling purposes, airport data are among the least desirable. Problems with location and the general quality of data are the primary concerns. The USEPA, in their Meteorological Monitoring Guidance for Regulatory Modeling Applications, summarizes these concerns about using airport data: For practical purposes, because airport data were readily available, most regulatory modeling was initially performed using these data; however, one should be aware that airport data, in general do not meet this guidance.73 L71 Office of Environmental Health Hazard Assessment,Chronic Toxicity Summary,Silica(Crystalline, Respirable),Final, February 2005. http://www.oehha.ca.gov/air/chronic_rels/pfd/SILICAcREL_FINAL.pdf 72 California Air Pollution Control Officers Association(CAPCOA), Air Toxics"Hot Spots" Program, Revised 1992 Risk Assessment Guidelines,October 1993. L73 USEPA,Meteorological Monitoring Guidance for Regulatory Modeling Applications,EPA454/R- 99-05,February 2000,p.1-1. L 47 L