Definition:
Percent of days tested exceeding the National Ambient Air Quality Standards (NAAQS) 24-hour standard for particulate matter (PM2.5). PM2.5 consists of particles less than 2.5 micrometers in diameter.

Why is this important:
All particles found in the air, such as dust, dirt, soot, smoke, and liquid droplets are particulate matter. Exposure to particulate matter, especially PM2.5 has been linked to causing or worsening lung (including asthma) and cardiovascular disease (heart disease and stroke). People with these diseases, adults age 65 and older, and infants and children are more likely to be affected by breathing PM 2.5, especially as levels rise.

Where are we:

During 2008 in Spokane County, 0 days out of 116 days that were tested exceeded the standard for PM2.5. The rate of poor air quality significantly decreased from 2004 to 2008.

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