Ravalli County Air Quality
In December 2007, Ravalli County’s three year, 24-hour air quality violated the EPA standard for particulate matter (PM 2.5). The EPA human health standard for PM 2.5 is 35 micrograms per cubic meter. Ravalli County’s three year, 24-hour standard was 37.7 µg/m3.
Based on these data (the average of 2004-2006 data), Ravalli County was submitted by the Governor of Montana as a non-attainment area.
In March 2008, Montana DEQ released a draft report of air quality data including 2007 data in which they report Ravalli County’s new three year, 24-hour average at 32.1 µg/m3, below the EPA human health standard. Ravalli County is still being considered by EPA as a non-attainment area, but EPA will consider the 2007 data when making their decision.
What is PM 2.5?
PM 2.5 particles are a fraction of the size of a human hair. Because of their size, they can travel deep in to the lung and the body cannot expel them.