Waterford City had the worst air quality in Ireland on Monday and Tuesday night.
High levels of particulate matter were detected by the Environmental Protection Agency at their station on Paddy Browne's Road.
Patrick Kenny is the Manager of Ambient Air Quality with the EPA, he said:
"What's driving that poor status for Waterford it's the date from PM2.5. There are very fine particles in our air.
"Those levels went quite high at that station over a number of hours and it's a rolling 24hr average which brought a value on the index 'as poor' on Monday and Tuesday."
Around 1,300 people die prematurely every year because of poor air quality.
Patrick Kenny says the domestic solid fuel burning is what caused the issues in Waterford this week:
"If you do have a solid fuel heating system consider the fuels that you're burning in that heating system.
"Particularly when we get to those colder, stiller air conditions and pollutant levels start to build up in a localised area."
