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Air Quality

Current Air Quality Index (AQI)* (updated hourly)

Daily Air Quality Index (AQI)* Report

Air Quality Index (AQI) Forecast (estimated future value)

Air Quality Data Archives (AQI) [historical data]  (may load slowly)

The AQI is an index for reporting daily air quality.  It tells you how clean or polluted your air is, and what associated health effects might be a concern.  The higher the AQI value, the greater the level of air pollution and the greater the health concern.

The AQI is derived by comparison to EPA standards from the following data readings:  Particulate Matter 2.5 continuous monitor on the Canton City Health Department's 2nd floor roof top and ozone monitors in Canton, Brewster, and Alliance. The Daily AQI report is based on the air quality for the period of 8 AM of the previous day to 8 AM of the current day. The current day AQI value is updated hourly automatically from the monitor equipment.

The daily air quality index is available by clicking the "Daily Air Quality Index (AQI) Report" link above, or from the Repository and WHBC , or by calling the Canton City Health Department at (330) 489-3385. You can also get the current day's AQI value, which is updated hourly, but clicking the "Current Air Quality Index (AQI) (updated hourly)" link above.

For more information on the air quality index, please visit U.S. Environmental Protection Agency.


*The Clean Air Act requires EPA to review National Ambient Air Quality Standards (NAAQS) every 5 years to determine whether they should be retained or revised. As a result of that regularly scheduled review, in October 2015, EPA strengthened the NAAQS for Ozone from 75 ppb to 70 ppb.

Ozone is a colorless gas that can be good or bad: Ozone in the stratosphere is good because it shields the earth from the sun's ultraviolet rays. Ozone at ground level, where we breathe, is bad because it can harm human health. Ozone forms when two types of pollutants (volatile organic compounds (VOC) and nitrogen oxides (NOx)) react in sunlight. These polluntatns come from sources such as vehicles, industries, power plants, and products such as solvents and paints.  Exposure to ozone can cause series health problems, including breathing difficulty, asthma attacks, lung damage, and early death from heart or lung disease.

In December 2015, the Air Quality Index (AQI), EPA’s tool for telling the public how clean or polluted the air is, is being updated to reflect this change. The revised AQI breakpoints are outlined in this table:

AQI Category

Index Values

Current (2008) Breakpoints in ppb (based on 8-hr average)

Revised (2015) Breakpoints in ppb (based on 8-hr average)









Unhealthy for Sensitive Groups








Very Unhealthy








More information about this change is available at

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