World

Smog smothers London as dirty European air, Sahara dust and traffic fumes fuel air pollution

  • In this general view of London, taken through glass, showing Tower Bridge, lower left, over the river Thames and looking east towards Canary Wharf, top, which is just visible through the haze and smog in London, Friday, April 10, 2015. Southern Britain and northern France are suffering high levels of air pollution due to stagnant air, though an atlantic weather system will bring fresher conditions Saturday. (AP Photo/Alastair Grant)

    In this general view of London, taken through glass, showing Tower Bridge, lower left, over the river Thames and looking east towards Canary Wharf, top, which is just visible through the haze and smog in London, Friday, April 10, 2015. Southern Britain and northern France are suffering high levels of air pollution due to stagnant air, though an atlantic weather system will bring fresher conditions Saturday. (AP Photo/Alastair Grant)  (The Associated Press)

  • In this general view of London, taken through glass, showing Tower Bridge and looking east towards Canary Wharf, top right, which is just visible through the haze and smog in London, Friday, April 10, 2015. Southern Britain and northern France are suffering high levels of air pollution due to stagnant air, though an Atlantic weather system will bring fresher conditions Saturday, according to weather forecast predictions. (AP Photo/Alastair Grant)

    In this general view of London, taken through glass, showing Tower Bridge and looking east towards Canary Wharf, top right, which is just visible through the haze and smog in London, Friday, April 10, 2015. Southern Britain and northern France are suffering high levels of air pollution due to stagnant air, though an Atlantic weather system will bring fresher conditions Saturday, according to weather forecast predictions. (AP Photo/Alastair Grant)  (The Associated Press)

  • Visitors to the Shard building viewing platform take photos of the City of London, with St Paul's Cathedral, seen at centre, with a layer of smog and haze visible above the city, in London, Friday, April 10, 2015. Southern Britain and northern France are suffering high levels of air pollution due to stagnant air, though an atlantic weather system will bring fresher conditions Saturday. (AP Photo/Alastair Grant)

    Visitors to the Shard building viewing platform take photos of the City of London, with St Paul's Cathedral, seen at centre, with a layer of smog and haze visible above the city, in London, Friday, April 10, 2015. Southern Britain and northern France are suffering high levels of air pollution due to stagnant air, though an atlantic weather system will bring fresher conditions Saturday. (AP Photo/Alastair Grant)  (The Associated Press)

Traffic fumes, dirty air blown in from Europe and Sarahan dust are combining to coat parts of Britain in smog.

The environment department says air pollution is "high" across much of the country Friday and could reach the top designation of "very high" in southeast England.

Officials say people with heart and lung problems or asthma should avoid exertion.

In London, haze clouded the view of landmarks including Tower Bridge and the Houses of Parliament from atop the Shard, Britain's tallest building.

Steven Godby, a geographer at Nottingham Trent University, said a contributing factor was North African dust that was "incorporated into a northerly airflow and can travel long distances before being deposited as far away as the U.K."

Officials say fresher air from the Atlantic should ease pollution Saturday.