High air pollution monitored in Derry
High levels of air pollution are being monitored in the Londonderry area, the Department of Agriculture, Environment and Rural Affairs has said.
Low levels of pollution are also being monitored in other parts of NI.
The department said there is a possibility that other urban areas will experience high air pollution as a result of current weather conditions.
The pollution is likely to continue overnight and into Monday, before improving from Monday evening onwards.
The high pollution levels are the result of the cold, calm weather conditions, which can lead to the build-up of emissions from vehicles and home heating.
During periods of high air pollution the symptoms of people with lung or heart disease may worsen. Healthy people are unlikely to experience any ill effects.
Hourly updates on levels of particulate matter, sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide are available on the department's website.