The air quality index has been developed to provide advice on expected levels of air pollution. In addition, information on the short-term effects on health that might be expected to occur at the different bands of the index (Low, Moderate, High and Very High) is provided here.

Short-term effects of air pollution on health

Air pollution has a range of effects on health. However, air pollution in the UK does not rise to levels at which people need to make major changes to their habits to avoid exposure; nobody need fear going outdoors.

Adults and children with lung or heart conditions: It is known that, when levels of air pollutants rise, adults suffering from heart conditions, and adults and children with lung conditions, are at increased risk of becoming ill and needing treatment. Only a minority of those who suffer from these conditions are likely to be affected and it is not possible to predict in advance who will be affected. Some people are aware that air pollution affects their health: adults and children with asthma may notice that they need to increase their use of inhaled reliever medication on days when levels of air pollution are higher than average.

Older people: are more likely to suffer from heart and lung conditions than young people and so it makes good sense for them to be aware of current air pollution conditions.

General population: at Very High levels of air pollution, some people may experience a sore or dry throat, sore eyes or, in some cases, a tickly cough - even healthy individuals.

Children: need not be kept from school or prevented from taking part in games. Children with asthma may notice that they need to increase their use of reliever medication on days when levels of air pollution are higher than average.

Action that can be taken

When levels of air pollution increase it would be sensible for those who have noticed that they are affected to limit their exposure to air pollutants. This does not mean staying indoors, but reducing levels of exercise outdoors would be reasonable.

Older people and those with heart and lung conditions: might avoid exertion on High pollution days.

Adults and children with asthma: should check that they are taking their medication as advised by their health practitioner and may notice that they need to increase their use of inhaled reliever medication.

Adults with heart and circulatory conditions: should not modify their treatment schedules on the basis of advice provided by the air quality index: such modification should only be made on a health practitioner's advice.

Some athletes: even if they are not asthmatic, may find their performance is less good than expected when levels of a certain air pollutant (ground-level ozone) are High, and they may notice that deep breathing causes some discomfort in the chest. This might be expected in summer on days when ground-level ozone levels are raised. This does not mean that they are in danger but it may be sensible for them to limit their activities on such days.