Children living in homes with wood burners could be exposed to over three times more pollution than those in non-wood-burning homes. The results come from a study that looked at air pollution experienced by primary schoolchildren in Wales.

Fifty-three children from two primary schools in Anglesey (Ynys Môn) were given backpacks equipped with air pollution sensors. They took the packs home and carried them during their journeys to and from school.

Dr Hanbin Zhang, from the University of Exeter and part of the study team, said: “One thing that stood out was the home environment. This was the largest contributor to children’s daily particle pollution​ exposure – more than school or commuting. This was mainly due to indoor sources such as wood burning and indoor smoking.”

Short peaks in particle pollution were linked to home cooking and secondhand tobacco smoke. Home heating with a fire or stove was linked to longer exposures. In some cases, these persisted overnight in children’s bedrooms as fires remained lit or smouldering with poor ventilation.

Prof Zhiwen Luo from Cardiff University, who led the study said: “During home hours, the average particle pollution in non-smoking homes with wood burners was about 13 micrograms per cubic metre compared with 3.5 micrograms per cubic metre in non-smoking homes without wood burners.

“The study is small, but the contrast was consistent and supports the conclusion that wood burning can substantially increase indoor particle pollution.”

One school was in Holyhead, and the other was in a rural area. We often think of towns and cities are being the most polluted places, but on average, researchers found urban children experienced less particle pollution, compared with those at the rural school.

The study took place in winter, and researchers attributed these differences to contrasts in wood burning. This took place in 21% of homes for the urban schoolchildren and 53% in the rural school.

A recent study in New Zealand pointed out the asthma risk for children in wood-burning homes. A previous study of 50,000 US women found those who used a wood burner at home had a 43% increased risk of lung cancer. The women were studied for an average of 11 years and the extra risk was seen in tobacco smokers and those who had never smoked.

Working with the children was an important part of the Anglesey study.

Dr Shuangyu Wei from Cardiff University, who was also involved in the study, said: “Children were helped to understand their own data, which prompted conversations and, in some cases, behaviour change. Schools told us that parents began discussing the results spontaneously and trying to work out what might be causing pollution inside their homes.”

Cooking added to the measured air pollution, especially when the backpacks were left close to the kitchen in the children’s homes. Short pollution peaks were also measured when children walked past bakeries and restaurants on the high street.

Particle pollution inside the schools was much lower than during travel and at home.

Children who walked to and from school experienced less pollution compared with children who were driven. Parental smoking while driving produced the highest concentrations measured in the study.

The UK government is consulting on health warnings for new stoves and solid fuels.