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Note: EPA no longer updates this information, but it may be useful as a reference or resource.
Please see www.epa.gov/nsr for the latest information on EPA's New Source Review program.
July 5, 1988 Air Quality Analysis for Prevention of Significant Deterioration (PSD) 6.22
The memo relays a policy decision on the approach to use to interpret dispersion modeling results to determine whether a source will cause or contribute to a violation of NAAQS or PSD increment. Under this approach, air quality concentrations are projected throughout the proposed source's impact area, but do not automatically cause a source to cause or contribute to a violation. Instead, where a modeled violation is predicted, further analysis is done to determine whether the impact is significant at the point and time of the modeled violation.Notebook Entries: 12.12; 12.13