Air quality is considered
satisfactory, and air pollution poses little or no risk.
Moderate
51-100
Air quality is acceptable;
however, for some pollutants there may be a moderate health concern for a
very small number of people who are unusually sensitive to air pollution.
Unhealthy for
Sensitive Groups
101-150
Members of sensitive
groups may experience health effects. The general public is not likely to be
affected.
Unhealthy
151-200
Everyone may begin to
experience health effects; members of sensitive groups may experience more
serious health effects.
Very Unhealthy
201-300
Health alert: everyone may
experience more serious health effects.
Hazardous
> 300
Health warnings of emergency conditions. The entire population is more
likely to be affected.
