Definitions in chapter 173-400 WAC apply to this chapter. Definitions specific to this chapter include:

"FEM" or "Federal Equivalent Method" means an EPA designated ambient air quality sampling and analysis method that has been designated as an equivalent method according to 40 C.F.R. Part 53. It does not include a method for which an equivalent method designation has been canceled according to 40 C.F.R. 53.11 or 53.16.

"FRM" or "Federal Reference Method" means an EPA designated ambient air quality sampling and analysis method specified in an appendix to 40 C.F.R. Part 50, or a method that has been designated as a reference method according to 40 C.F.R. Part 53. It does not include a method for which a reference method designation has been canceled according to 40 C.F.R. 53.11 or 53.16.

"mg/m3" means milligrams per cubic meter.

"Period" means any interval of the specified time.

"PM" means particulate matter.

"ppbv" means parts per billion by volume.

"ppmv" means parts per million by volume.

"µg/m3" means micrograms per cubic meter.