There are three main sources of air pollution from canal boats:

• Fuel combustion in a boat’s engine (or generator if a separate machine is used to provide electrical power and recharge batteries)

• Fuel combustion for heating (especially wood and coal)

• Cooking food - from the food itself and from any fuels that are used

These sources of air pollution are not exclusive to canal boats: heating systems in buildings; engines in road vehicles, trains and other machines; and domestic and commercial cooking all produce air pollution.

As air pollution from road vehicles and construction machinery has reduced in London, the relative significance of other sources has increased. Some attention has shifted away from London’s roads and towards the need to support a transition away from combustion heating systems.

For some sources of heating-derived air pollution there are options for reducing or avoiding emissions. For example, using mains gas or electric heating instead of using a log burner or open fireplace, or replacing a gas boiler with a heat pump.

These changes may not be possible for a canal boat due to a lack access to mains electricity or grant funding support that may be available for homeowners.

Many canal boaters have already taken steps to reduce environmental impacts, and many more would like to make improvements but experience a barrier in the form of prohibitive costs or technological limitations.

People living on boats, their live-aboard neighbours and other people living, working or going to school nearby may be exposed to air pollution from canal boats. This may especially be the case during winter when there is a greater need for heating and power.

Indoor air quality

Some of the common indoor sources of air pollution are:

• Using gas hobs for cooking

• Burning food or cooking food without opening a window for ventilation

• Burning wood or coal in a log burner or open fireplace

• Lighting candles or incense (especially paraffin and scented candles)

• Using scented cleaning or personal care products, including aerosols, room sprays, and air fresheners

• Decorative materials and new furnishings, for example freshly-painted walls, new carpet or upholstery or new pressed wood products

Research from the London School of Economics (‘Making the invisible visible’, February 2025) investigated indoor air quality inside a range of homes and found that indoor air pollution was often worse than the air outdoors, especially during evenings.

This and other research suggests that our activities indoors are dominant in terms of their impact on indoor air quality and our exposure to air pollution at home.

This means that a home in a neighbourhood with low levels of outdoor air pollution could still have high levels indoors, due to normal day-to-day activities like cooking, using scented products, and burning candles and incense. On the other hand, even homes in built-up areas or near to busy roads could have good indoor air quality with diligent ventilation and an awareness of the common sources of indoor air pollution.

In 2022 the London Borough of Islington commissioned Imperial College London to measure indoor air quality onboard several boats. This was done in order to better understand how the provision of electrical power supplies at visitor mooring areas could help to reduce the exposure of boaters to air pollution from diesel engines.

The independent analysis (‘Investigating sources of indoor pollution on canal & river boats’) revealed that high levels of black carbon air pollution (a type of particulate matter, PM) from boat engines was found to be entering the indoor living area. Using a solid fuel burning stove was also observed to be contributing to indoor pollution, along with cooking.