The Environmental Protection Agency designated Missoula as a moderate nonattainment area for PM10 in 1990 due to violations of the PM10 National Ambient Air Quality Standards (NAAQS) in the 1980s. At that time, Missoula's PM10 pollution was primarily due to road dust and residential wood smoke. In response to the nonattainment designation, Missoula adopted several rules into the Missoula City-County Air Pollution Control Program which signficantly reduced the area's PM10 pollution. These rules include paving requirements, sanding and street sweeping requirements, deicer requirements and the woodstove removal program. As a result of the implementation of these rules, Missoula has not exceeded the NAAQS since 1989. The Missoula City-County Health Department is now seeking redesignation to attainment for PM10. As part of the redesignation request, MCCHD is submitting a Limited Maintenance Plan (LMP) for PM10.
The Missoula City-County Air Pollution Control Board held a public hearing at 12:15 P.M. on Thursday, December 18, 2014 at the Missoula City-County Health Department, second floor conference room at 301 West Alder to take public comment on the proposed PM10 Redesignation Request and Limited Maintenance Plan and its incorporation into the Montana State Implementation Plan.
The Air Pollution Control Board adopted the PM10 Redesignation Request and Limited Maintenance Plan at the December 18, 2014 meeting.
The PM10 Redesignation Request and Limited Maintenance Plan is currently awaiting a submission letter from the Governor of Montana and will then be formally submitted to the EPA for approval.