PSI Value

Health Advisory

0 to 50

(Good)

None for the general population

51 to 100

(Moderate)

None for the general population

101 to 200

(Unhealthy)

Persons with existing heart or respiratory ailments should reduce physical exertion and outdoor activity.

The general population should reduce vigorous outdoor activity.

201 to 300

(Very unhealthy)

Elderly and persons with existing heart or lung disease should stay indoors and reduce physical exertion and outdoor activity.

The general population should avoid vigorous outdoor activity.

301 to 400

(Hazardous)

Children, elderly and persons with existing diseases should stay indoors and avoid outdoor activity.

The general population should avoid all unnecessary outdoor activity.

> 400

(Hazardous)

Children, elderly and persons with existing diseases should stay indoors, keeping the windows and doors closed and avoiding physical exertion as far as possible.

Outdoor activity should be avoided.

The general population should keep physical exertion and outdoor activity to as low a level as possible.

24-hr PM2.5 concentration (µg/m³)

Health Advisory

0 to 15

None

>15 to 40

None for the general population.
Unusually sensitive people should consider reducing prolonged or heavy exertion.

> 40 to 65

Following groups should reduce prolonged or heavy outdoor exertion:

·         People with heart or lung disease

·         Children and older adults

Everyone else should limit prolonged or heavy exertion.

> 65 to 150

Following groups should avoid all physical activity outdoors:

·         People with heart or lung disease

·         Children and older adults

Everyone else should avoid prolonged or heavy exertion.

> 150 to 250

Following groups should remain indoors and keep activity levels low:

·         People with heart or lung disease

·         Children and older adults

Everyone else should avoid all physical activity outdoors.