Britain on health alert over air pollution: Moderate warning for Wiltshire and Swindon

Experts said the smog could cause fatal asthma attacks and have warned the elderly and those with health problems to be cautious.

Swindon and Wiltshire residents have been told the warning is at moderate level. Wales and the West Country have higher warning levels.

The Department for Environment, Food and Rural Affairs (Defra), said air pollution was blowing in from Europe and mixing with home-grown smog to create the problem.

Officials warned this could trigger health difficulties for those with respiratory illnesses and the elderly, although it does not pose a health threat for the general population.

Large parts of England will see air pollution climb to moderate levels today while parts of the north will see it hit nine out of 10.

A Defra spokeswoman said: "Winds bringing in pollution from the continent, combined with locally generated pollution and still weather conditions has led to some high pollution measurements across the UK.

"Levels are expected to return to low by Friday."

Most of Wiltshire is on a level 5 warning with Swindon at 4 - at the lower end of the Moderate scale.

• A map of air pollution today. Source: Defra

Defra's Moderate warning means: Adults and children with lung problems, and adults with heart problems, who experience symptoms, should consider reducing strenuous physical activity, particularly outdoors. Enjoy your usual outdoor activities.

Kay Boycott, chief executive of Asthma UK, said: "Two thirds of people with asthma find that air pollution makes their asthma worse, putting them at an increased risk of a potentially fatal asthma attack.

"When air pollution is high it's vital people with respiratory conditions including asthma check air pollution forecasts, carry their reliever inhaler with them at all times, and ensure that they are taking their preventer inhaler every day because this will help build resilience to asthma triggers like air pollution."