Air Quality Index

The Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted the air is, and what associated health concerns you should be aware of. The AQI focuses on health effects that can happen within a few hours or days after breathing polluted air. The Environmental Protection Agency uses the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. For a chart explaining the related health impacts for each range of exposure, view the Health Chart.

On March 12, 2008 the Environmental Protection Agency revised the AQI for ozone to reflect changes to the naional ambient air quality standards for ground-level ozone. Under the revised AQI, ozone levels above 0.075 ppm would be considered in the "unhealthy for sensitive groups" category - known to many people as "code orange" air quality day. When ozone is in this category, the EPA recommends certain groups adjust their activity levels to reduce their ozone exposure. These groups include children and adults who are active outdoors, people with asthma or other lung diseases and older adults.

Ozone Concentration (ppm) (8-hour average, unless noted)	Air Quality Index Values	Air Quality Descriptor
0.0 to 0.059	0 to 50	Good
0.060 to 0.075	51 to 100	Moderate
0.076 to 0.095	101 to 150	Unhealthy for Sensitive Groups
0.096 to 0.115	151 to 200	Unhealthy
0.116 to 0.374	201 to 300	Very Unhealthy

Health Chart

Ozone Level	Health Effects and Protective Actions for Specific Ozone Ranges
Good	What are the possible health effects? No health effects are expected.
Moderate	What are the possible health effects? Unusually sensitive individuals may experience respiratory effects from prolonged exposure to ozone during outdoor exertion. What can I do to protect my health? When ozone levels are in the "moderate" range, consider limiting prolonged outdoor exertion if you are unusually sensitive to ozone.
Unhealthy for Sensitive Groups	What are the possible health effects? If you are a member of a sensitive group,⁽¹⁾ you may experience respiratory symptoms (such as coughing or pain when taking a deep breath) and reduced lung function, which can cause some breathing discomfort. What can I do to protect my health? If you are a member of a sensitive group,⁽¹⁾ limit prolonged outdoor exertion. In general, you can protect your health by reducing how long or how strenuously you exert yourself outdoors and by planning outdoor activities when ozone levels are lower (usually in the early morning or evening).
Unhealthy	What are the possible health effects? If you are a member of a sensitive group,⁽¹⁾ you have a higher chance of experiencing respiratory symptoms (such as aggravated cough or pain when taking a deep breath), and reduced lung function, which can cause some breathing difficulty. At this level, anyone could experience respiratory effects. What can I do to protect my health? If you are a member of a sensitive group,⁽¹⁾ avoid prolonged outdoor exertion. Everyone else-especially children-should limit prolonged outdoor exertion. Plan outdoor activities when ozone levels are lower (usually in the early morning or evening).
Very Unhealthy	What are the possible health effects? Members of sensitive groups⁽¹⁾ will likely experience increasingly severe respiratory symptoms and impaired breathing. Many healthy people in the general population engaged in moderate exertion will experience some kind of effect. According to EPA estimates, approximately: - Half will experience moderately reduced lung function. - One-fifth will experience severely reduced lung function. - 10 to 15 percent will experience moderate to severe respiratory symptoms (such as aggravated cough and pain when taking a deep breath). People with asthma or other respiratory conditions will be more severely affected, leading some to increase medication usage and seek medical attention at an emergency room or clinic. What can I do to protect my health? If you are a member of a sensitive group,⁽¹⁾ avoid outdoor activity altogether. Everyone else-especially children-should limit outdoor exertion and avoid heavy exertion altogether.

¹ Members of sensitive groups include children who are active outdoors; adults involved in moderate or strenuous outdoor activities; individuals with respiratory disease, such as asthma; and individuals with unusual susceptibility to ozone.

Source: EPA's 1999 publication "Smog-Who Does it Hurt?"

The West Michigan Clean Air Coalition is a partnership of businesses, academic institutions, government agencies, industry, and non-profit organizations in Kent, Ottawa, Muskegon, and Kalamazoo counties working together to achieve cleaner air in the region through the education and promotion of voluntary emission reduction activities.

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