In the UK, low carbon heating sources such as biomass stoves and boilers are an important component of climate change mitigation strategies, offering the potential to reduce the reliance on natural gas, heating oil and LPG. Although there are many associated benefits, some wood burning stoves, multifuel stoves and open fireplaces can also be a significant source of air pollution. As a result, domestic burning (which includes stoves, fireplaces, barbeques and bonfires) is a high priority within the governments recently released Clean Air Strategy .
The majority of new stoves are designed to meet EcoDesign emission standards – ready for its implementation in 2022 – however traditional stoves and fireplaces can be some of the most inefficient and polluting forms of domestic heating. Knowledge of the stoves location, the fuels they are burning and how they are being used contains large amounts of uncertainty, therefore improving the data on these factors is vital for local authorities to plan their emission reduction strategies. Replacing older stoves with EcoDesign models, disseminating good practices on stove use and communicating the importance of fuel quality can help reduce emissions while continuing to mitigate climate change.
Although the levels of many air pollutants are falling, concentrations in a number of urban areas are higher than those recommended by the World Health Organisation (WHO). Exceedance of WHO air pollution limits causes a wide variety of health problems and disproportionally affects young and elderly people. Every year it is estimated that air pollution causes 40,000 premature deaths and 6 million sick days, costing the economy over £22 billion . Consequently, air pollution in the UK has been declared a ‘public health emergency’.
The pollutants of greatest concern are oxides of nitrogen (NOx) and particulate matter (PM). Fine particles with diameters of 2.5 micrometres or less (PM2.5) are the most damaging to health as they penetrate furthest into the lungs.
Both the UK High Court and the European Court of Human Rights have ruled that there is an urgent need to improve air quality in the UK and that current policies to address the problem are “unlawful”. Following a legal battle, the UK government is facing multimillion euro fines unless drastic action is taken. The government’s draft Clean Air Strategy, published in May 2018, aims to reduce PM emissions by 30% by 2020, and by 46% by 2030. Combustion sources such as vehicles, power stations, industry and domestic burning are the largest contributors to both PM2.5 and NOx emissions.
Residential or domestic burning has been covered extensively within the Clean Air Strategy and the UNFCCC Guidelines for National Greenhouse Gas Reporting . This includes combustion sources in domestic and commercial buildings such as gas boilers, barbecues, chimineas, bonfires, open fireplaces and heating stoves.
These sources are responsible for around 14% of all greenhouse gas emissions in the UK, mainly a result of the CO2 produced from gas boilers and cookers. Uptake of renewable heating technologies has been limited and the sector has been slow to decarbonise compared to others. Low carbon heating sources such as biomass stoves and boilers have great potential to reduce our reliance on natural gas, heating oil and LPG in order to combat climate change. This has been recognised by the Government through policies such as the Renewable Heat Incentive (RHI) and has been successful, particularly in off-grid areas.
Today, the amount of domestic burning in urban areas is increasing again as a result of high fuel prices, aesthetics and a desire for green living. Emissions from modern, top-of-the-range wood burning stoves are relatively low, however older stoves and open fireplaces account for the highest emissions in this sector; a factor that is exacerbated through the use of dirty fuels such as coal, waste and wet wood. Across Europe, the WHO estimated that burning these fuels was responsible for 61,000 premature deaths in in 2010, an increase of 23% since 1990 .
The exact contribution of domestic burning to total air pollution is highly uncertain. This is a result of very little data on the number, the location and the use of stoves, fireplaces, barbeques and chimineas. In addition to the used appliance, emissions are also highly dependent on fuel type and user behaviour.
Extensive research and analysis has found that domestic burning can be the lead source of ambient air pollution in certain global locations (over 90% contribution), particularly during winter. The contribution of domestic burning in the UK is much lower than other countries – the traffic sector is considered the biggest contributor of many pollutants – however it still has a significant contribution. The latest, best estimates for the UK – as quoted in the Clean Air Strategy – are that domestic burning contributes between 13-38% of PM emissions [4,5], although there are still many knowledge gaps that remain. Further research is therefore a necessity before we can fully understand the true contribution of domestic burning.
It is already illegal to use open fires and dirty fuels in a Smoke Control Area. Outside of these areas, using ‘DEFRA exempt’ stoves and fuels can reduce emissions. From 2022, new stoves will also need to meet stricter emissions limits through the Ecodesign Regulations. Modern ‘Ecodesign ready’ stoves are very well designed and emit up to 80% less pollution than traditional stoves and open fires, and are cleaner than ‘DEFRA exempt’ stoves. In the Government’s draft Clean Air Strategy, the suggested actions include:
There are several other policy- and technology-based methods to control emissions. Please get in touch with us to find out more.
Mitchell, E.J.S. 2017. PhD Thesis. University of Leeds