Solid fuel burning and particulate pollution


It isn’t just road traffic that pollutes our city. Burning wood or other solid fuel in homes pollutes the air, causes health problems and can create a nuisance for neighbours.

The tiny particles in smoke can enter the bloodstream and enter internal organs, risking long term health issues as well as having more immediate impacts on some people, such as exacerbating breathing problems or triggering asthma attacks.

A growing problem:

In Bristol we follow the national trend that has seen an increase in solid fuel burning and the installation of wood burners. In most cases this will be as a form of secondary heating rather than as the main source of domestic heating.

How polluting are wood burning stoves?

Burning domestic solid fuels leads to emissions of PM2.5, which is harmful to human health.

A Clean Air Act (Defra exempt for Smoke Control Areas) wood burning stove emits more than 10 times as much particulate matter as a Euro VI HGV – these are the most recent lorries from 2015 onwards.

A non-Defra exempt stove typically emits 8 times as much pollution as a Defra exempt one.

Open fires are worse still, and it is illegal to burn wood on an open fire in the home.

Where is the problem?

We are undertaking more monitoring to understand the level of particulate pollution in different parts of the city.

Regulations and wood-burning:

The whole of Bristol is a smoke control area (SCA) which aims to ensure emissions from solid fuel are controlled to some extent. This means that people can either:

a) burn an authorised smokeless fuel in any appliance


b) are permitted to burn a wider range of fuels if using an exempt Defra exempt alliance. A Defra exempt appliance is a burner that is designed to burn fuel efficiently to reduce emissions (however these still emit high levels of pollution – see above)

Breach of these rules in Bristol can result in a fine of up to £1,000. It is an offence to burn wood on an open fire in Bristol under the smoke control regulations.

What fuels are burned in domestic fires and stoves?

  • Traditional house coal (or bituminous coal) – a naturally occurring mined product. PM2.5 emissions are higher than from smokeless fuels
  • Smokeless coal (or anthracite) – a form of naturally occurring, mined, high-purity coal, authorised for use in smoke control areas
  • Manufactured solid fuels – fuels manufactured from coal products with other ingredients that have low smoke emissions. However, some do have high SO2 emissions
  • Wet wood – a naturally occurring product. Newly felled wood has a high moisture content and creates a lot of smoke when burned. It has more than double the emissions of seasoned or kiln dried wood
  • Seasoned wood – wood that has been left for at least 2 years to naturally air dry
  • Kiln dried wood – wood that has been kiln dried to below 20% moisture

What can householders do to reduce pollution?

The advice for people living in urban areas is:

  • Thinking of buying a wood burning stove? If you have a gas boiler or other clean heating in your household, and you are concerned about pollution, then don’t
  • If you do have an open fire or non-compliant stove don’t use it unless you have no other source of heating, and then use smokeless fuel suitable for use in a Smoke Control Area
  • If you have an exempt stove and have a clean source of heating as well, think about when you use it – maybe reduce its use to special occasions and avoid high pollution times and days with no wind
  • If you are using your exempt stove use the best, most seasoned wood you can use and consider buying a moisture meter
  • Visit the Woodsure Ready to Burn site for more information
  • Never burn any MDF, tanalised, varnished or painted wood or other waste material as treated wood releases carcinogens and other toxins as well as particulate matter – and they come into your house as well as out into the city air.