Air pollution: High levels to spread across England

Pollution levels across parts of England, including London, are set to get worse on Wednesday
Government health warnings have been issued amid warnings pollution spreading across England will again hit high levels later.
Defra issued the warnings after high pollution levels were recorded Tuesday.
The pollution - a mix of local and European emissions and dust from the Sahara - is forecast in parts of south England, the Midlands and East Anglia.
The elderly and those with lung or heart disease are urged to avoid strenuous exercise outside.
http://www.bbc.co.uk/news/uk-26844425