Unlike the criteria pollutants, toxics do not have National Ambient Air Quality Standards (NAAQS) making evaluation of their impacts more subjective. Because there are no standards established for MSAT not a lot of policy and guidance documents are available. Note that the interim guidance document is not a substitute for any laws or regulations, thus do not impose legally binding requirements on EPA, DOT, states, or the regulated community.
Interim Guidance or PDF (203KB) - This FHWA interim guidance provides a tiered approach for analyzing MSAT in NEPA documents. Depending on the specific project circumstances, FHWA has identified three levels of analysis.
PDF files can be viewed with the Acrobat® Reader®