As a result, non-ambient air can include areas subject to video surveillance, signage, security patrols, or other measures provided that the measures “provide reasonable assurance that the general public will not have access.” Under the EPA’s revised draft policy, a source may use various “measures,” not limited to mere “physical barriers,” to preclude public access. The EPA now believes that its prior characterization that “physical barriers” must exist to exclude an area as ambient air is unnecessarily limiting. This policy was rooted in the EPA’s interpretation of the definition of ambient air under 40 CFR §50.1(e), rather than explicit regulatory language. Through various guidance documents and letters, the EPA’s historic policy has been to only exclude those areas from the definition of ambient air that are (1) owned or under the control of the source and (2) not accessible by the public due to some physical barrier (like a fence). Thus, excluding areas from “ambient air” eliminates the need to model emissions impacts on those areas.
Areas where access is not available are not “ambient.” Sources are often required under the NAAQS and the EPA’s PSD program to model facility impacts on ambient air. Under current EPA regulations, ambient air is broadly defined as the portion of the atmosphere (external to buildings), that the general public has access. The revised policy will most notably affect sources that have to model air quality around their facilities to demonstrate compliance with National Ambient Air Quality Standards (NAAQS), as well as sources applying for air construction permits under the EPA’s Prevention of Significant Deterioration (PSD) permitting program.
0 kommentar(er)
