sábado, 19 de fevereiro de 2022

Wood burners emit more particle pollution than traffic, UK data shows

Revised government data estimates a lower proportion of pollution comes from wood stoves but they remain a ‘major contributor




Wood burning in homes produces more small particle pollution than all road traffic in the UK, according to revised government data.

The new data significantly cuts the estimated proportion of small particle pollution that comes from wood burners from 38% to 17%. But wood burning pollution remains a “major contributor” to particle pollution, another government report said. Road transport is responsible for 13% of particle pollution.

The data shows tiny particle pollution, called PM2.5, produced by wood burning rose by a third from 2010 to 2020, when it reached 13,900 tonnes a year. This all comes from the 8% of homes that have wood burners, 95% of which have other sources of heating. The data revision was made after a survey of 50,000 homes provided updated information on the use of wood stoves.

Particle pollution is well known to damage health and cause early deaths. “These toxins may enter the bloodstream and be transported around the body, lodging in the heart, brain and other organs,” the report said. “Therefore, exposure can result in serious impacts to health.”

The report also found that since the late 2000s, significant decreases in particle pollution from coal burning, industry and vehicles have been “largely offset by increases in emissions from wood burning in domestic settings and [biomass] burning by industry”.

“Even after this revision, home use of solid fuel is one of the top two sources of particle pollution in the UK, coming from just 8% of UK homes,” said Gary Fuller, at Imperial College London and a member of the Air Quality Expert Group that advises the government.

“My in-box is filled with people who are concerned about the wood smoke that is filling the bedroom of their asthmatic child or ill elderly relative.”

The government data on wood burning pollution is based on laboratory tests of stoves. Fuller said: “We need to remember the lessons from VW and dieselgate, where the air pollution produced in the real world was much greater than those in official tests. Data from New Zealand tells us that the same applies to wood burners, with the way that we light fires and the fuels that we use tending to lead to more air pollution than we expect from official tests.”

“What is staggering is the increase between 2010 and 2020,” said Simon Birkett, of the campaign group Clean Air in London. “There’s still a really big problem. It’s a public health catastrophe, so wood-burning stoves need to be banned urgently. The first step should be to stop the sale or installation of them.”

Other recent research has shown that wood-burning stoves in urban areas are responsible for almost half of people’s exposure to the cancer-causing chemicals found in air pollution particles. Even wood-burning stoves meeting the new “ecodesign” standard still emit 750 times more tiny particles than a modern HGV truck, another study found, while wood burners also triple the level of harmful pollution inside homes and should be sold with a health warning, according to scientists.

The data revision was made after the government conducted a new survey of wood burning in 50,000 homes, the biggest to date. Its estimate of domestic wood consumption was substantially lower than the previous survey.

The government said the reasons for the different results were likely to include previous assumptions that may be wrong, including that most new stoves were not replacements for old stoves and that users did not sometimes mix coal with their wood. Another factor was that the previous estimate included the “Beast from the East” cold period, which the new estimate did not.

“However, it is clear that UK residential emissions from domestic combustion will continue to be a major contributor to the UK emissions of particulate matter,” the survey report concluded.

The sector producing the biggest proportion of PM2.5 is manufacturing industries and construction, which is responsible for 27%. But Fuller said: “Lots of people live closer to home chimneys than they do to industrial sources and major motorways. This leads to greater exposure to wood burning pollution than we find for many other sources.”

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