The AQI focuses on what you might experience if exposed within a few hours or days after breathing polluted air.
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The Environmental Protection Agency calculates the AQI using 5 major air pollutants regulated by the Clean Air Act:
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The AQI runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern.
The index is divided into six categories, each corresponding to a different level of health concern.
WATCH | If Canadian wildfires continue, what does that mean for us?
If Canadian wildfires continue, what does that mean for us?
An AQI of over 100 triggers an alert for vulnerable groups.
Levels over 300 signal a health emergency and everyone is more likely to be affected.
The air quality in New York City and across the northeast is the worst since record-keeping began in 1999 because of the wildfire smoke from Canada, officials said.
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Learn more about the index from the EPA at AirNow.gov.
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