A study at NUI Galway has found that emissions from so-called 'green' fuels like wood and peat - including pellets - have regularly breached World Health Organisation guidelines.

It comes after high levels of air pollution were recorded in Dublin over a two-month period.

Dense black smog once choked Dublin skies before smoky coal was banned from the capital in 1990.

Over the past number of decades there has been a marked shift from the burning of fossil fuels to low-carbon greener alternatives like wood, peat and pellets.

However the study published in the international journal, Nature Sustainability, has found that emissions from wood burning fuels were causing high levels of air pollution in Dublin city.

The study was conducted over a two-month period between November 2016 and January 2017 when residential consumption was high.

Dr Jurgita Ovadnevaite is the author of the report and says that these emissions are a serious health concern and could see the return of city smog if not brought under control. 

She said the climate policy shift from fossil fuels to carbon-neutral fuels was driven by the need to tackle greenhouse gases and climate change.

However the emissions from residential solid fuel burning were equally damaging to health and the environment.

Professor Colin O'Dowd is the Director of NUI Galway's Centre for Climate and Air Pollution Studies.

He said the disproportionate sensitivity of air pollution levels to solid fuel is of particular concern as these fuels are growing in popularity and set to double in consumption across Europe by 2020.

"These striking results also illustrate the importance of considering the wider impacts of climate policy to avoid negative health impacts, as occurred with diesel vehicles, and ensure positive co-benefits and win-win outcomes, so that actions to mitigate against climate change benefit air quality and vice versa."