Air pollution from home wood burning is estimated to lead to 8,600 premature deaths in the US each year, according to research.
Just 2% of US homes use wood for primary heating. Another 8% burn wood for pleasure, aesthetics or supplementary heating, but combined they produce 21% of the country’s wintertime particle pollution.
Prof Daniel Horton, of Northwestern University, who led the new study, said: “We frequently hear about the negative health impacts of wildfire smoke, but we rarely consider the consequences of burning wood to heat our homes.”
Kyan Shlipak, first author of study said: “I was shocked by the percentage of particle pollution coming from residential wood burning. There were big evidence gaps on the continental US-wide air quality effects – where the pollution is, and who is most affected by it.”
The research team divided the continental US into 839,000 grid squares. Hourly pollution was calculated for for each square, once with residential wood combustion and once without.
Shlipak said: “We had the preconceived notion that residential wood combustion was predominantly a rural phenomenon, but we found that it has a substantial impact on urban and suburban populations in and around many of the US’s largest cities.”
Owing to cold night-time temperatures, wood burning also affected places considered to have warm climates, including Los Angles. In parts of the US, the wood-burning pollution is trapped locally by valleys and mountains. Examples include the Rocky Mountains west of Denver, the Cascade Range to the east of Seattle, and the San Gabriel mountains north of Los Angeles.
Next, the researchers looked at who was doing the burning and who was most affected. They found that particle pollution from residential wood combustion spread from suburbs with high rates of burning to affect people in densely populated parts of cities. This has environmental justice implications.
Shlipak said: “We were surprised by the result. Although people of colour burn less wood, they experienced higher exposure and greater harms from wood-burning pollution.”
The impact on people of colour was compounded by increased vulnerability owing to longstanding health inequalities.
Horton said: “Only a small number of homes rely on wood burning for heat. Facilitating a home-heating appliance transition to cleaner burning or non-burning heat sources could lead to outsized improvements in air quality.”
The UK also experiences the negative health effects of residential wood and coal burning.
UK wide, air pollution from homes that burn wood or coal contributes to almost 2,500 avoidable deaths a year. A recent study in Wales found that heating with a wood stove or fireplace tripled the particle pollution breathed by children at home.
Analysis of 26m home energy performance certificates found that 10.4% of homes in England and Wales had wood heating in 2024, and it is increasing. The charity Global Action Plan estimates that if trends continue, nearly 1m wood-burning stoves could be installed in the UK over the course of the current parliament.
The greatest density of wood stoves and fireplaces is in urban areas outside the main cities, including Worthing, Norwich, Reading, Cambridge and Hastings councils. This wood heating is predominantly in homes in wealthier neighbourhoods but spreads to cover larger areas, raising questions of environmental justice.
The UK government is now consulting on health warnings for new stoves and solid fuels.