Concentration of SO2, µg/m3

Levels in terms of human health

Precautions

0 - 50

Good

-

51 - 100

Reasonable

-

101 - 150

Unhealthy for sensitive groups

Asthmatic people should limit physical exertion outdoors in these areas.

151 - 200

Insalubrious

Children, asthmatics and people with heart or lung diseases should limit physical exertion in outdoor areas.

201 - 300

Insalubrious

Physical exertion should be avoided in these outdoor areas for children, asthmatics, and people with heart or lung diseases. It is recommended that you also avoid physical efforts in these areas.

301 - 500

Very toxic

Children, asthmatics and people with heart or lung diseases should stay indoors; other individuals should avoid outdoor efforts.