The use of peat, wood and coal to heat homes is the biggest threat to air quality in Ireland, environmental chiefs have warned.
European experts estimate that 1,480 people died prematurely in 2014 as a direct result of solid fuels being burned in open fires and stoves.
The worst offending towns over the course of last year were Longford and Ennis, the Environmental Protection Agency (EPA) said.
But monitoring sites in Finglas, Marino, Rathmines and Coleraine Street in Dublin; Heatherton Park in Cork and Claremorris, Co Mayo and Bray, Co Wicklow also picked up pollution levels above World Health Organisation (WHO) guidelines.
Exhaust fumes are the second biggest issue for air quality, the EPA said.
It noted that the worst levels of nitrogen dioxide, which comes mainly from vehicles, was recorded on one day in Swords.
Laura Burke, the EPA's director general, said: "It has become increasingly clear that there are no safe level of pollutants and with this in mind, it is time to tackle the biggest issue impacting on air quality in Ireland - emissions from solid fuels in our small towns around the country."
The ban on smoky coal in cities is expected to be extended nationwide next year.
The EPA warned that if vehicle numbers continue to rise, Ireland is at risk of breaching strict European limits in towns and cities on nitrogen dioxide.
And it said research is beginning to show that farming, particularly ammonia from intensive piggeries and poultry farms, is adding to the concentrations of fine particulate matter known as PM2.5.
Elsewhere, the analysis showed that polycyclic aromatic hydrocarbons, which are also produced by burning solid fuels, were above European Environmental Agency guidelines in Rathmines, Dublin, Heatherton Park in Cork, Galway city and Castlebar.
Its latest air quality report said: "The continued promotion of the shift from solid fuel as a method of home heating to cleaner alternatives, is the key issue regarding particulate matter levels in Ireland and the area where there is the greatest scope for improvements in air quality.
It added: "Priority should be given to public transport or clean transport over fossil fuel powered motor vehicles in all aspects of society."
The EPA report was released alongside a new national air quality monitoring programme which will have 38 new automatic monitoring stations providing real-time information to the public by 2020.