N.M. Admin. Code § 20.2.14.300
A method is specified for use in sampling the emissions from stationary coal-burning equipment for particulate matter of less than two microns (2u) equivalent aerodynamic diameter. This procedure shall be used for testing emissions from coal-burning equipment operating in the State of New Mexico for compliance with 20.2.14 NMAC (Particulate Emissions from Coal Burning Equipment), as specified within the regulation. It is generally intended that sampling for fine particulates, as described below, be carried out only on those stacks (or ducts) which are controlled for gross particulates and which have already been demonstrated to be in compliance with the sections of the regulation for total particulate emissions.
N.M. Admin. Code § 20.2.14.300