NCHRP Project 25-17 is intended to assess the expected effects of the national ambient air quality standards for ozone and particulate matter (PM 2.5) on transportation planning, project development, and implementation of transportation system improvements. One of the key issues in any discussion of these new standards is a determination of which areas of the county will be affected, particularly which areas will likely be designated as attaining the standards and which areas are likely to be designated as not attaining the standards. While NCHRP Project 25-17 will be able to accomplish a strong analysis for ozone, it will only be able to do a preliminary assessment based on limited information for PM 2.5 related to PM 10. There is a need for a more robust assessment based on a broader range of available data and information such as visibility, PM 1.0, and PM 2.5. This task has been added to the existing work plan and contract for NCHRP Project 25-17.