Published Tuesday, 11 December 2012
The calm weather is believed to have contributed to the build up of emissions. (© Getty)
Armagh, Newry and Strabane were worst affected on Tuesday and are being monitored.
The high levels may have been caused by the build up of emissions from vehicles and central heating from homes during the recent calm, cold weather conditions which the region has experienced.
People with lung or heart disease may find that their symptoms worsen during periods of high air pollution, the department added.
Meanwhile, Ballymena, Belfast, Lisburn and Derry areas are experiencing moderate levels.
It is predicted that the conditions could persist throughout the rest of Tuesday and Wednesday.
The situation is expected to improve with the arrival of more unsettled weather conditions from Thursday.
Air Quality NI telephone: 0800 556677
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