Integrated Science Assessments (ISAs)

[NOTICE] EPA is announcing the availability of the first external review draft of the Integrated Science Assessment for Oxides of Nitrogen, Oxides of Sulfur, and Particulate Matter – Ecological Criteria for public review and comment and an independent peer review. 

EPA has set National Ambient Air Quality Standards (NAAQS) for six principal criteria air pollutants, which include oxides of nitrogen, oxides of sulfur, particulate matter, carbon monoxide, ozone and lead. Numerous sources emit these "criteria pollutants", which are considered harmful to public health and the environment. Since 2008, EPA’s Integrated Science Assessments (ISAs) have formed the scientific foundation for the review of the NAAQS standards. Prior to this, Air Quality Criteria Documents provided the scientific foundation for the NAAQS process; as part of a streamlining of the NAAQS process these documents were replaced by the ISAs.  To date, EPA has developed (or is in the process of developing) the following ISAs to help support reviews of the primary (human health-based) and secondary (welfare-based, e.g. ecology, visibility, materials) NAAQS:

Calendar of Workshops and Meetings


Clean Air Scientific Advisory Committee (CASAC), which provides independent advice to EPA on the technical basis for the NAAQS, is the primarily reviewing authority for the ISAs.

The CASAC Calendar includes a complete list of past and future meeting details.