Forecasting air pollution

The average person breathes in 14 kilograms of air every day. With every lungful, we inhale vital oxygen, but also small amounts of potentially harmful elements.

Air quality forms a significant risk factor for various health conditions and can also aggravate existing conditions, such as respiratory disease.

Like clouds moving through the sky, pollution is transported from one place to another by winds. Does this mean it is possible to forecast air pollution?

The answer lies at the European Centre for Medium-Range Weather Forecasts in Reading, in southern England.

Working in partnership with meteorological and research centres across Europe, scientists have developed the largest global air quality forecasting model, which delivers better information than individual ones.

“Every day we receive millions of observations here in this room – observations from satellites flying about 800 kilometres above the Earth looking at the atmosphere. We also receive observations from the surface, like measurement stations all over the world, ships, airplanes etc,” says Richard Engelen, Project Manager at the EU-funded MACC-II (Monitoring Atmospheric Composition and Climate) project.

The pollutants monitored include carbon monoxide, ozone, nitrogen dioxide and sulphur dioxide.

“Among the various pollutants that we study, there is, for example, dust from the desert. We can see here a beautiful image of a dust plume coming from the desert, wrapping around and going towards southern Europe and affecting air quality in this region. How do we get a forecast from this data? The data is elaborated on super-computers using sophisticated algorithms that mimic the laws of physics. The forecast for yesterday is then compared with the observations for today to produce the forecast for tomorrow,” says senior scientist Angela Benedetti.

The data is stored in a massive computer. The combination of millions of daily observations and the predictive power of computer models is the real strength of the forecast service.

So what is it used for?

“You can think of citizens who are sensitive to high levels of pollution like people with asthma, who need to know what the conditions will be for the next few days. There are authorities and cities or regions that need to change, for instance, traffic control based on air quality measurements that can use our forecasts to anticipate the situation. There are authorities in regions or countries who want to be aware of the trans-boundary transport of pollutants so they can adjust their measures based on that information,” says Richard Engelen.

One of these authorities is the State Agency for Nature and Environment in North Rhine Westphalia, Germany’s most heavily industrialised state. Scientists use the pollution forecasts from Reading and add local information.

Monitoring and forecasting air pollution here is vital: the area produces a third of Germany’s electricity using coal, and it’s the world’s second largest steel production site. These monitoring stations provide a detailed picture of air quality in the region, producing information that is relevant to people with breathing difficulties, for instance, or to local authorities, enabling them to introduce temporary measures to try and reduce pollution peaks in cities.

Actions all aimed at making the air we breathe a little less toxic for future generations.