Federal reference methods are EPA approved methods for sampling criteria pollutants for national air quality monitoring. These specifications dictate the type of monitoring equipment used, the procedures followed, and sampling frequency.
Sources: US. EPA. 2013. Technology Transfer Network Ambient Monitoring Technology Information Center - PM 2.5 - Federal Reference Method (FRM). Accessed on 11 September 2013. Available at http://www.epa.gov
United States. 2009. Title 40 Code of Federal Regulations Part 52 Approval and Promulgation of Implementation Plans 53.1 -Definitions. Accessed on 11 September 2013. Available at: http://www.ecsr.gov