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First and foremost, the Fresno airport data are not site-specific to the Project site. The distance involved (112 miles) makes the airport data clearly not site- specific, with numerous land use classifications existing between the Project and the airport. Most important, however, are the difference in land uses at the Project and the airport, respectively. Fresno Airport is comprised of concrete runways, parking lots, passenger terminals, and other structures associated with air travel activities. These surface and building characteristics in turn affect the boundary layer meteorology present at the airport.74 In addition, landings, takeoffs, and idling of airplanes affect the site-specific conditions at the airport such that the meteorological conditions are not representative of the area surrounding the Project site. The other major issue is the quality of the meteorological data collected at Fresno airport. Airport data are not collected with the thought of air dispersion modeling in mind. For example, airport conditions are typically reported once per _ hour, based on a single observation (usually) taken in the last ten minutes of each B-58 cont. hour. The U.S. EPA recommends that sampling rates of 60 to 360 per hour, at a minimum, be used to calculate hourly-averaged meteorological data 75 Air — dispersion modeling requires hourly-averaged data, which represents the entire hour being modeled, and not only a snapshot taken in one moment during the hour. In addition, data collected at Fresno Airport are not subject to the system accuracies required for meteorological data collected for air dispersion modeling. The U.S. EPA recommends that meteorological monitoring for dispersion modeling use equipment that are sensitive enough to measure all conditions necessary to verify compliance with the national ambient air quality standards and Prevention of Significant Deterioration C'PSD") increments (and these same conditions apply for risk assessments). For example, low wind speeds (down to 1.0 meter per second) are usually associated with peak air quality impacts- this is because modeled impacts are inversely proportional to wind speed. Following U.S. EPA guidance, wind speed measuring devices (anemometers) should have a starting threshold of 0.5 meter per second or less 76 The wind speed measurements should be accurate to within plus or minus 0.2 meter per second, with a measurement resolution of 0.1 meter per second 77 74 Oke T.R.,Boundary Layer Climates,Halsted Press,1978,pp.240-241. 75 USEPA,Meteorological Monitoring Guidance for Regulatory Modeling Applications, EPA-454/R- — 99-05,February 2000,p.4-2. 76 Id.,p.5-2. 77 Id.,p.5-1. 48