The EPA National Exposure Research Laboratory can designate a measurement device using an established technological basis as a Federal Reference Method (FRM) to certify that the device has undergone a testing and analysis protocol, and can be used to monitor NAAQS compliance.  Devices based on new technologies can be designated as a Federal Equivalent Method (FEM).  FEMs are based on different sampling and/or analyzing technologies than FRMs, but are required to provide the same decision making quality when making NAAQS attainment determinations.  Approved new methods are formally announced through publication in the Federal Register.  A complete list of FRMs and FEMs is available.