Quality Categories Explained

Hazardous

Serious aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; serious risk of respiratory effects in the general population.

Visibility
< .7 Miles

Everyone should avoid any outdoor exertion; people with respiratory or heart disease, the elderly, and children should remain indoors.

Very Unhealthy

Significant aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; significant risk of respiratory effects in the general population.

Visibility
.7-1.1 Miles

People with respiratory and heart disease and the elderly and children should avoid any outdoor activity; everyone else should avoid prolonged exertion.

Unhealthy

Increased aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly, increased respiratory effects in the general population.

Visibility
1.2-2.74
Miles

People with respiratory or heart disease, the elderly and children should avoid prolonged exertion; everyone else should avoid prolonged exertion.

Unhealthy for Sensitive Groups

Increasing likelihood of respiratory symptoms in sensitive individuals, aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly.

Visibility
2.75-4.44
Miles

People with respiratory or heart disease, the elderly and children should limit prolonged exertion

Moderate

Possibility of aggravation of heart or lung disease among persons with cardiopulmonary disease and the elderly.

Visibility
4.45 - 11.5
Miles


Good

Visibility
>11.6 Miles

How We Calculate Air Quality