The Air Quality Index (AQI) is a measurement that helps us understand air pollution levels, and how they may impact the natural environment and human health. The higher the AQI, the greater the level of air pollution. The AQI provides an easy way to determine whether you should enjoy the outdoors as usual or should consider planning an indoor activity to reduce exposure to elevated levels of polluted air. The AQI includes six categories and when forecasted conditions are expected to reach 126 or higher for ground-level ozone, a Spare The Air alert is issued.
The Air Quality Index (AQI) is a measurement that helps us understand air pollution levels, and how they may impact the natural environment and human health. The higher the AQI, the greater the level of air pollution. The AQI provides an easy way to determine whether you should enjoy the outdoors as usual or should consider planning an indoor activity to reduce exposure to elevated levels of polluted air. The AQI includes six AQI categories and when forecasted conditions are expected to reach 126 or higher for ground-level ozone, a Spare The Air alert is issued.
301+
Hazardous
201-300
Very Unhealthy
151-200
Unhealthy
100-150
Unhealthy for sensitive groups
50-100
Moderate
0-50
Good
301+ – Hazardous
201-300 – Very Unhealthy
151-200 – Unhealthy
100-150 – Unhealthy for sensitive groups
50-100 – Moderate
0-50 – Good
0 – 50 is Good
Air quality is satisfactory, and air pollution poses little or no risk.
51 – 100 is Moderate
Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
101 – 150 is Unhealthy for Sensitive Groups
Members of sensitive groups may experience health effects. The general public is less likely to be affected.
151 – 200 is Unhealthy
Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
201 – 300 is Very Unhealthy
Health Alert: The risk of health effects is increased for everyone.
301+ is Hazardous
Health Warning of Emergency Conditions: Everyone is more likely to be affected.
Five major pollutants
EPA measures an AQI for five major air pollutants to protect public health including:
- ground-level ozone
- particle pollution (also known as particulate matter, including PM2.5 and PM10)
- carbon monoxide
- sulfur dioxide
- nitrogen dioxide