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Advice to Public

Air Pollution Index (API)

Advice to Public

Health effects from air pollution come about due to a combination of the concentration of the air pollutants and the amount of time you are exposed to the air pollution. Brief exposure to moderately high pollution levels will normally not lead to any significant problem. For most of us, therefore, the general API is more relevant as it represents the air pollution that we shall be exposed to for most of the time. For the Roadside API, although it is naturally higher on a given day due to the close proximity to vehicle emission sources, it is less relevant as we often spend only quite short periods of the day in busy streets and roads. It will be of more interest to those who spend several hours each day close to busy roads.

The suggested precautionary actions are summarised below:

Air Pollution Level
API
Advice to Public
General API
Roadside API
Severe a 201-500 The general public are advised to reduce physical exertion and outdoor activities The general public are advised to avoid prolonged stay in areas with heavy traffic. If it is necessary to stay in streets or roads with heavy traffic, they are advised to reduce physical exertion as far as possible.
Very High   f 101-200 Persons with existing heart or respiratory illnesses (such as coronary heart and cardiovascular diseases, asthma, chronic bronchitis and chronic obstructive airways diseases)are advised to reduce physical exertion and outdoor activities Persons with existing heart or respiratory illnesses (such as coronary heart and cardiovascular diseases, asthma, chronic bronchitis and chronic obstructive airways diseases) are advised to avoid prolonged stay in areas with heavy traffic. If it is necessary to stay in streets or roads with heavy traffic, they are advised to reduce physical exertion as far as possible.
High a 51-100 No immediate response action is suggested --
Long-term effects may, however, be observed if exposed at this level persistently for months or years
Medium  a 26-50 No response action is required.
Low  a 0-25 No response action is required.

As the health effects on individuals may vary, you should seek advice from a medical doctor if you are in doubt or feel uncomfortable. If you are a smoker, you should quit smoking now!

Health Effects

 

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Last revision date: 28 April 2006