The current Mayor of London, Sadiq Khan, is reported to have said that wood-burning stoves could be banned in some areas to combat air pollution under proposals – this could include hand-loaded industrial wood burning heaters that are not fitted with any abatement equipment for the reduction of fine particulate matter. Chris Franklin MD at Ranheat Engineering Ltd, a leading UK manufacturer of wood combustion equipment-continues his series of articles exclusively for Furniture and Joinery Production. In this issue he looks at hand-loaded heating systems and their alleged effect on pollution.

Geraint Davies, Labour chair of the All-Party Parliamentary Group on Air Pollution, who has backed the move, said: ”Wood burners are creating pollution hotspots in middle-class areas and cause tens of thousands of cases of avoidable children’s asthma attacks, premature dementia, and early deaths.

The popularity of wood-burners has soared in the past decade but emissions of one of the most harmful types of air pollution have increased by 35% between 2010 and 2020.

Known as PM 2.5, particulate matter less than 2.5 microns in diameter invisible to the naked eye and small enough to pass through the lungs and into the bloodstream.

If we are to reach World Health Organisation targets in London by 2030, then we must take tougher action on wood-burning stoves and the mayor is taking a welcome first step as wood burners and coal already make up 40% of PM2.5 particulate pollution.

Wood-burning stoves, which would be banned under the proposals for urban areas with poor air quality, are increasingly popular. They are most popular in south-east England, where 16% of households have them, compared with 5% nationally.

It is estimated that between a quarter and a third of all of London’s fine-particle pollution comes from domestic wood burning. In January, during a period of very high air pollution, it contributed half the toxic emissions in some areas of the capital, according to King’s College London research.

Khan said: “Non-transport sources contribute half of the deadly emissions in London, so we need a hard-hitting plan of action to combat them similar to moves I am taking to reduce pollution from road vehicles.

“With more than 400 schools located in areas exceeding legal pollution levels, and such significant health impacts on our most vulnerable communities, we cannot wait any longer, and I am calling on government to provide the capital with the necessary powers to effectively tackle harmful emissions from a variety of sources.”

The Mayor has asked the environment department to amend the Clean Air Act to allow for the creation of zero-emission zones where the burning of solid fuel is not allowed from 2025 onwards.

With the threat of continually rising conventional fuel costs and the banning of gas boilers and heaters in the future the use of readily available alternative fuels is essential but not if this has an adverse effect on air quality.

So, what can be done about this?

Since 2012 Ranheat has been working on its range of ceramic flue gas filtration units.

The Renewable Heat Incentive introduced a minimum standard for flue gas emissions from biomass fuelled boilers.

Ranheat Ceramic Filter unit

Warm air heaters were excluded from the scheme and hand loaded systems would not meet the stringent requirements of the scheme.

Wood burning boilers and heaters fitted with ceramic flue gas filtration are regularly tested by independent laboratories as part of the part B permitting regulations that require all appliances burning wood-waste at a rate over 90kg per hour to have an annual test carried out. The limit for particulate is 60mg/m3. With a Ranheat ceramic flue gas filter fitted the results are consistently below 2mg/m3

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