ENV-00-190 Modeling Impacts to Class I Areas under the Prevention of Significant Deterioration Program

Description:

Under the federal Prevention of Significant Deterioration (PSD) program, major new sources and major modifications at major sources may be required to predict their impacts to certain types of nearby parks and wilderness areas called Class I areas. PSD applicants must address the impact of their projects on air quality related values (AQRVs), as directed by the Federal Land Manager (FLM). Major AQRV impairments include visibility reduction and the deposition of acidic species (e.g., sulfur). FLMs have recently become more active in the PSD permitting process, requiring attention from PSD applicants. Recent guidance developed by multi-agency workgroups recommending techniques used to assess impacts to AQRVs are discussed. Advanced dispersion modeling techniques used to model impacts of PSD projects to distant (up to 200km) Class I areas are presented.