Mobile pollution warning

The air pollution in Central London and the London borough of Croydon is being forecast daily as part of an ESA-backed project.

The ‘YourAir’ service predicts levels of the pollutants nitrogen dioxide, ozone and airborne particles – exposure to which can harm people with asthma, lung and heart problems, and in the very highest concentrations can harm otherwise healthy people.

The forecasts include predictions of overall effects on health on an index from one to ten. Unlike previous systems, YourAir resolves air pollution down to the scale of individual streets – highest levels are often found along routes with heavy traffic or other pollution sources, so information on street-by-street changes in pollution help vulnerable people make informed choices about their travel routes.

The prototype service, which covers Central London and Croydon in South London, is being developed by Cambridge Environmental Research Consultants (CERC) as a demonstration service of ESA's PROMOTE project.

PROMOTE is itself part of Global Monitoring for Environment and Security (GMES), a joint initiative between ESA and the European Union to integrate all available space- and ground-based information sources to develop an independent European environmental monitoring capacity from planetary to local scales.

"The YourAir service works by combining data from the various sources available," said Iarla Kilbane-Dawe of CERC. "It combines regional air quality forecasts provided by PROMOTE with information on local road traffic patterns.

"We also employ information from monitoring stations around the city. Because their coverage is limited they don't help with generating forecasts, but serve as a key way of validating our results, which so far have been around 90% accurate. For the next stage of the project we aim to improve the accuracy further by integrating other data sources, especially satellite observations and more data on traffic patterns."

Regional air quality information is important because not all the pollution affecting a city actually originates there. Depending on the weather, studies show that up to half the air pollution found in some European cities might have come from elsewhere in the continent – the Ruhr in Germany for instance, or as far away as Italy's Po Valley.

Satellite-based atmospheric sensors such as Envisat's Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) can monitor such movement of air pollution, and so provide constraints for the model used for air pollution forecasts, increasing their accuracy.

A linked project called airTEXT involves sending a text message to the mobile phones of a thousand vulnerable individuals during the evening before days when air pollution may be moderate or high. The message will also advise on steps they can take to minimise their pollution exposure and manage their symptoms.

Also backed by PROMOTE, AirTEXT is a partnership between CERC, Croydon Council, the Croydon Primary Care Trust and the South West London Health Protection Unit.