Any Prevention of Significant Deterioration (PSD) permits issued on or after April 12 that include significant increases in NO2 emissions must contain a demonstration that the source's allowable emissions will not cause or contribute to a violation of the new 1-hour NO2 NAAQS.  Since EPA has not promulgated a 1-hour NO2 significant impact level, this means that any increase in allowable emissions must be modeled in conjunction with all other NO2 emissions in the area to ensure that there are no modeled violations of the 1-hour NO2 NAAQS.  For more information, review the IDNR article.