New research across six European towns and cities suggests that children’s exposure to home wood-burning may be as significant as their exposure to traffic exhaust.
Scientists measured the air inside buildings where children spend much of their time—schools, sports centres and homes—focusing on polycyclic aromatic hydrocarbons (PAHs), a group of pollutants released when fuels are burned.
Dr Barend van Drooge, from Barcelona’s Institute for Environmental Assessment and Water Research (IEAWR) and senior author of the study, said: “Some of these compounds are linked to cancers after prolonged exposure, as recognised by the International Agency for Research on Cancer, and there is evidence that they can delay cognitive development.”
Measurements were taken in and around Athens, Barcelona, Colchester, Copenhagen, Helsinki and Lisbon.
Van Drooge continued: “Urban areas with wood-burning, such as Colchester and Athens, had the highest PAH levels. Barcelona and Lisbon, where wood-burning is not practised, had the lowest levels.”
In Colchester and Athens, PAH exposure exceeded World Health Organization guidelines.
Maria Antonia Aretaki, of the IEAWR in Barcelona and first author of the study, said: “Understanding the pollutants in children’s everyday surroundings is an important step towards protecting their health. Children are particularly important given their vulnerability to environmental pollutants and the potential health implications of exposure during childhood.”
Sports centres had the lowest concentrations, followed by schools—although some, especially in Lisbon, were affected by nearby busy roads. Ventilation and indoor sources mattered, but the homes with some of the highest PAH levels were in areas with wood-burning, and many had open fireplaces and stoves.
Winter PAH concentrations were higher than summer levels.
The researchers divided PAHs into two types according to molecular weight. In Colchester homes, high-molecular-weight PAHs in winter were more than 10 times those in summer; low-molecular-weight PAHs were about three times higher.
Van Drooge continued: “Wood-burning is known to be an important emitter of PAH, but it was surprising that it has become such an important contributor to the overall presence of PAHs in urban areas. However, none of the cities exceeded unacceptable limits for lifetime cancer risk.”
Within the UK, the impacts of wood-burning are unlikely to be unique to Colchester. Separate analysis of energy performance certificates by researchers at University College London showed that Colchester ranked 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 from two primary schools in Anglesey (Ynys Môn) found that children living in homes with wood burners could be exposed to more than three times as much particle pollution as those in homes without wood burners. The Anglesey study also found that homes had more air pollution than schools.
In Greece, wood-burning increased during the financial crisis that began in 2008. Heating oil costs soared and many people turned to wood heating. This contributed to an increase in deaths associated with particle pollution in Athens, especially among people aged over 70. In some Greek towns, wood-burning leads to PAH levels that are 100 times higher in winter than in summer.
