How heating with wood pollutes the air we breathe

Pollutants from heating with wood

The Federal Environment Agency (UBA) assumes that almost 12 million so-called single-room furnaces are currently used for heating with wood in Germany. Although the operation of traditional coal stoves is declining, the number of modern fireplace and tiled stoves, which are often used as a second heat source, is increasing.

The emission of carbon dioxide(more on the measured value CO₂) when burning wood for heating, which is becoming increasingly popular, can often be put into perspective by the fact that the trees grown for the wood previously absorbed a similar amount of CO₂ - provided the firewood did not have long delivery routes.

However, this calculation often ignores the fact that further pollutants are released through the burning of organic substances. Wood combustion in particular has a greater impact on the air than other energy sources such as oil and natural gas. The following pollutants are particularly decisive here:

• particulates(more on particulates here)
• Polycyclic aromatic hydrocarbons (PAH)
• Carbon monoxide(more on carbon monoxide poisoning here)
• Nitrogen oxides(more on measured value nitrogen dioxide)
• Sulphur dioxide(more on sulphur dioxide)
• chlorine-containing compounds (more on VOCs)

Danger due to incomplete combustion

The greatest danger is posed by incomplete combustion of the wood. In addition to toxic carbon monoxide(more on carbon monoxide poisoning here), methane is also produced(measured value methane), which contributes 21 times more to global warming than CO₂.

Organic compounds in the ash and exhaust air, such as polycyclic aromatic hydrocarbons, can also cause cancer. The particulates emitted also pollutes the respiratory tract, irritates the mucous membranes and increases the formation of plaque in the blood vessels, which can lead to strokes and cancer. It is also suspected that there is a connection between increased particulates pollution and neurological diseases (e.g. dementia and Parkinson's disease).

Reduce respiratory air pollution

If it is not possible to do without wood-burning appliances, the following aspects should be taken into account in order to reduce the pollution of the breathing air caused by heating with wood:

1. Make sure you have a low-emission and energy-efficient system. Open fireplaces are not only inefficient heat sources and pose a particular fire hazard. They also pollute the indoor air particularly strongly due to very high, uncontrollable emissions. Excessive operation of closed stoves should also be avoided in order to reduce the burden on health - including that of the neighbours.
   
2. Follow the manufacturer's and the chimney sweep's instructions to ensure the correct handling of your system. This includes both the proper lighting of the stove and the correct disposal of ash as well as regular maintenance and monitoring of the system by qualified personnel.
   
3. Consider the use and proper storage of the fuel. It is forbidden or unsuitable to burn treated or painted wood as well as fibreboard or chipboard and plywood.
   This means that only untreated and dry wood is suitable as fuel. To avoid too much smoke development and too much ash with low energy yield, the residual moisture in the wood should not exceed 25 %. To be on the safe side, use a wood moisture meter.
   
4. Note that burning unsuitable fuels endangers the health of all people in the direct and indirect vicinity. This makes the burning of unsuitable materials - depending on the type and extent - an administrative offence or even a criminal offence. Thus, for the protection of the general public, when burning treated or damp wood, paper or cardboard, garden waste, plastics or other waste, the polluter should be made aware of the prohibition. If the misconduct is repeated or there is no compliance, the local public order office or the environmental agency as the responsible authorities should be informed.
   
5. If you feel annoyed by a small fireplace and the consequences of heating with wood in your neighbourhood, you should first have an open discussion with the respective neighbours in order to reach an amicable agreement. The responsible chimney sweep can help to identify sources that are difficult to localise. The public order office can also mediate in such cases.
   A precise air measuring device, such as air-Q, can help you to understand the pollutant load in detail.
   
6. Pay attention to the origin of the wood when you order firewood or pellets, for example, on the internet. Firewood from primeval forests in Eastern Europe, which is often illegally cut down and imported, is not a sensible alternative.

From a comfort point of view, heating with wood is an interesting alternative to heating with oil or gas. However, it is only really in line with climate protection if the details described are observed.

(Image: unsplash/ Gardi Design)