High air pollution continues in north west of Northern Ireland as temperature set to remain low

The Department of Agriculture, Environment and Rural Affairs announced a high pollution episode on Sunday at the start of the recent cold snap. On Tuesday, the department said localised high and moderate levels of air pollution from particulate matter are once again being experienced in the north west of Northern Ireland.

Temperatures overnight on Monday fell to minus 9C in Castlederg, Co Tyrone, with sub-zero temperatures set to continue to the weekend, according to the Met Office. The department said the weather situation may cause this pollution to persist.

"The high levels of pollution are believed to be as a result of local pollution - home heating emissions and the current cold, calm weather conditions in which pollutants are not being dispersed," the department said in a statement.

"During periods of high pollution the symptoms of people with lung or heart disease may worsen. "Healthy people are unlikely to experience any ill effects."Read More: Big freeze could be coming to an end but impact expected to last until weekend