Air pollution alert for London and the south east. Image: http://www.london.gov.uk

Air pollution is expected to be high over London today with the authorities warning asthma sufferers and those with health conditions to take precautions.

The Department for Environment, Food & Rural Affairs, DEFRA,  announced at 5 am:

Levels of air pollution are forecast to become High in many areas of eastern and especially south eastern England where levels could reach Very High for a time.

This is due to a combination of pollutants trapped near the ground, a light southeasterly flow bringing additional pollutants from the continent and, in addition, a small amount of Saharan dust in the air. Across the rest of the United Kingdom, levels of air pollution are expected to be mainly Moderate.

DEFRA forecast air pollution map issued yesterday. Darker reds indicate higher levels of pollution expected. Image: DEFRA

The government advises adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly if they experience symptoms.

People with asthma may find they need to use their reliever inhaler more often.

Older people should also reduce physical exertion.

As there is a risk of very high air pollution the advice is stepped up to ‘avoidance’ of physical exertion.

The advice to the general population is that anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors.

City Hall has the following advice for Londoners wishing to reduce exposure to air pollution:

• Walk or cycle short journeys. You’ll help to reduce London’s pollution, and studies show you’ll reduce your own exposure too, as pollution is worse in a car
• Consider car sharing with people at work or school if you have to drive. This could save you time and money too
• Always switch off your engine when stationary. It’s better for the environment and saves fuel
• Use backstreets when you walk or cycle if possible – this can reduce your exposure to pollution by up to 50 per cent. You can find suitable route options on Google Maps and the walk4life website