Air pollution 'serious issue', says Public Health England
2 April 2014 Last updated at 09:32 BST
Air pollution across southern England, the Midlands and East Anglia is a result of dust from the Sahara adding to the UK's own levels of pollution, Public Health England has said.
Dr Paul Cosford, the body's director for health protection, told BBC Radio 4's Today programme that current levels of pollution in the most affected areas amount to a "serious issue".
But he added that the "vast majority" will not experience any adverse health consequences.
First broadcast on BBC Radio 4's Today programme on Wednesday 2 April.