II. Definition

  1. Environmental Protection Agency (EPA) has >1000 air quality monitoring stations around U.S.
  2. EPA reports the Air Quality Index for a given day
    1. Based on the highest individual pollutant levels for a given monitoring station
    2. Pollutants monitored include
      1. Ozone
      2. Particulate matter
      3. Carbon Monoxide
      4. Nitrous Oxides
      5. Sulfur dioxide
      6. Lead
  3. Each pollutant is assigned a maximal level above which it is unsafe
    1. Known as National Ambient Air Quality Standards (NAAQS)
    2. Air Quality Index values represent the pollutants percentage of the NAAQS unsafe level value
    3. Example, if ozone has a NAAQS of 0.075 ppm averaged over 8 hours
      1. Air Quality Index 50: Ozone measurement of 0.037 ppm over 8 hours
      2. Air Quality Index 100: Ozone measurement of 0.075 ppm over 8 hours
      3. Air Quality Index 150: Ozone measurement of 0.112 ppm over 8 hours

III. Interpretation

  1. Air Quality Index 0-50: Good
  2. Air Quality Index 51-100: Moderate
    1. Affects very sensitive people to either ozone or particulate matter
    2. Those at risk should avoid prolonged exposure or heavy exertion outdoors
  3. Air Quality Index 101-150: Unhealthy for sensitive groups
    1. High risk groups should avoid prolonged exposure or heavy exertion outdoors
    2. High risk groups
      1. Lung disease
      2. Heart disease (limit exposure if high particulate matter exposure)
      3. Children and young adults
      4. Athletes and other people with heavy outdoor exertion
  4. Air Quality Index 151-200: Unhealthy
    1. Everyone should avoid prolonged exposure or heavy exertion outdoors
  5. Air Quality Index 201-300: Very unhealthy
    1. Everyone should limit exposure and any exertion outdoors

IV. Resources

  1. EPA AirNow
    1. http://airnow.gov/

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