Ministers have unveiled a new system for classifying air quality in a bid to improve the information available to asthmatics and those with breathing problems.

The Department of Environment, Food and Rural Affairs set out plans to simplify air pollution information bulletins with the introduction of a new numbered system alongside the existing pollution guidelines of low, moderate, high and very high.

Low will be 1-3, moderate 4-6, high 7-9 and very high 10. The new numbers will appear on pollution bulletins on the internet, Teletext and Ceefax.

Environment minister Michael Meacher says the move underlines the government's commitment to ensure those at risk from pollution are given a clear indication of air quality.

"It is important that people have access to the most up to date information on air quality as quickly as possible. It means that vulnerable people can better assess the impact of current air pollution on their health," he said.

Meacher also hopes the new system will raise awareness about pollution levels. "And when pollution levels are high, it also means everyone canplay their part by considering what action they can take individually to cut pollution," he said.

The move has been welcomed by the National Asthma Campaign.

"It is important that people with asthma who are affected by air pollution can easily identify the daily air quality levels and thus be able to judge the likely impact on their symptoms. This is key to managing the condition so they know if they need to take more preventer medication for a short period or if indeed they may be better off staying indoors," a spokesman said.

However, the organisation believes there is still a need for more monitoring stations and one consistent approach across all media outlets to avoid confusion.