Home wood-burning rivals traffic fumes for kids' pollution exposure

Researchers measured air inside the places children spend their days — schools, sports centres and homes — across Athens, Barcelona, Colchester, Copenhagen, Helsinki and Lisbon. They were hunting for polycyclic aromatic hydrocarbons (PAH), a family of pollutants released when fuels burn. Colchester and Athens, both wood-burning cities, recorded the highest PAH levels, while Barcelona and Lisbon, where wood-burning is not practised, had the lowest. In Colchester and Athens, exposure topped WHO guidelines.

Dr Barend van Drooge of Barcelona's Institute for Environmental Assessment and Water Research, the study's senior author, flagged the stakes: some of these compounds are linked to cancers after prolonged exposure, as recognised by the International Agency for Cancer Research, and evidence suggests they delay cognitive development. He added that no city exceeded unacceptable limits for lifetime cancer risk.

First author Maria Antonia Aretaki, also at the Barcelona institute, said understanding the pollutants in children's everyday surroundings is an important step towards protecting their health, pointing to children's particular vulnerability to environmental pollutants. Sports centres came out cleanest, followed by schools — though some, especially in Lisbon, were affected by nearby busy roads. Ventilation and indoor sources mattered, but the homes with the greatest PAH sat in wood-burning areas, and many had open fireplaces and stoves.

Winter made everything worse. In the Colchester homes, high-molecular-weight PAH in winter were more than 10 times their summer levels, while low-molecular-weight PAH ran around three times higher. Van Drooge said it was surprising that wood-burning, a known PAH emitter, had become such an important contributor to the pollutants' overall presence in urban areas.

The UK picture isn't unique to Colchester. A separate analysis of energy performance certificates by University College London researchers ranked Colchester 120th out of 333 local councils for density of wood burners per square kilometre — Worthing, Norwich and Reading all had around four times more. A wintertime study of 53 children at two primary schools in Anglesey (Ynys Môn) found those in homes with wood burners could be exposed to over three times more particle pollution than children in non-wood-burning homes, and that homes were more polluted than schools.

Greece offers a cautionary tale. Wood-burning climbed during the financial crisis that began in 2008 as heating oil costs soared and households switched to wood, contributing to more deaths linked to particle pollution in Athens, particularly among people aged over 70. In some Greek towns, wood-burning pushes winter PAH levels 100 times higher than in summer.