The Environmental Protection Agency uses its Air Quality Index to provide general information to the public about air quality and associated health effects. An Air Quality Index (AQI) of 100 for any pollutant corresponds to the level needed to violate the federal health standard for that pollutant. For nitrogen dioxide, an AQI of 100 corresponds .053 parts per million (averaged over 24 hours) -- the current federal standard. Short-term health effects for NO2 do not occur until index values are above 200; therefore, an AQI value is not calculated below 201 for NO2. An index value of 201 for NO2 corresponds to an NO2 level of 0.65 parts per million (averaged over 24 hours).
|EPA Air Quality Index||Levels
|0 - 50||Good||None|
|51 - 100||Moderate||None|
|101 - 150||Unhealthy for
|151 - 200||Unhealthy||None|
|201 - 300||Very Unhealthy||Children and people with respiratory disease, such as asthma, should limit heavy outdoor exertion.|
|301 - 500||Hazardous||Children and people with respiratory disease, such as asthma, should limit moderate or heavy outdoor exertion.|