EPA Collaborative Website & 1-Hour NO2 NAAQS PSD Program

EPA Launches a Collaborative Web Site for Integrated Environmental Modeling

The U.S. Environmental Protection Agency has launched a new on-line tool for scientific collaboration and knowledge sharing that was built by Purdue University with support from the agency. The Integrated Environmental Modeling Hub (iemHUB) allows environmental researchers to analyze environmental problems and combine environmental models so that a better understanding of the environment can be developed – everything from keeping beaches clean to predicting climate effects.

EPA uses integrated modeling assessments to inform decision making in support of its broad mission of protecting human health and safeguarding the environment. With the website, the agency is providing a state-of-the-art resource to the environmental modeling community. The iemHUB supports the development of integrated models and their use in conducting research and informing the decision making process.

The iemHUB is being released by the EPA-supported Community of Practice for Integrated Environmental Modeling (CIEM). The Community of Practice is an informal collaborative organization that was set-up by EPA and other scientists to advance the state of the science and technology related to integrated modeling.

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Guidance on the Implementation of the 1-hour NO2 NAAQS for PSD Program‏

On June 30, 2010 EPA issued guidance for implementing the new 1-hour NO2 NAAQS under the PSD permit program, in the form of two memoranda.

The first guidance memorandum, “General Guidance for Implementing the 1-hour NO2 National Ambient Air Quality Standard in Prevention of Significant Deterioration Permits, Including an Interim 1-hour NO2 Significant Impact Level,” provides guidance for the preparation and review of PSD permits with respect to the new 1-hour NO2 standard. In addition, it sets forth a recommended interim 1-hour NO2 significant impact level (SIL) that EPA intends to use in issuing PSD permits under the federal PSD program, and that states with EPA-approved PSD programs may consider when carrying out the required PSD air quality analysis for NO2, until EPA promulgates a 1-hour NO2 SIL via rulemaking.

The second memorandum, “Applicability of Appendix W Modeling Guidance for the 1-hour NO2 National Ambient Air Quality Standard,” includes specific modeling guidance for estimating ambient NO2 concentrations and determining compliance with the new 1-hour NO2 standard.