Home heating

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What's burning?

Home fires are a major source of air pollution in some areas of the Waikato region. During winter the air can become so dirty that when we breathe it in it becomes a risk to our health and wellbeing.

Contaminants from home heating are generally more of a problem in winter when wood burners and open fires tend to be used. This happens especially in inland towns, such as Tokoroa and Te Kuiti where frequent calm conditions and inversion layers mean the smoke stays around.

Wood is a popular fuel for home heating. But the use of old wood burners and wet wood, is the main cause for PM₁₀ pollution. Theycan produce large amounts of contaminants that affect our air quality, and the fine particles are small enough to get into your lungs and can cause serious health problems - especially for young children, elderly, and asthmatics.

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Smoke (small particles)
Carbon dioxide and carbon monoxide
Nitrogen dioxide

Smoke (small particles)

Smoke consists of very small particles (PM¹⁰) that are less than 10 microns across - a fifth of the size of a human hair. These particles can get into our lungs causing health problems, especially for people with asthma, small children and the elderly.
Smoke can also reduce visibility and make it unpleasant to be outside at certain times of the day.
The particles in smoke are unburnt and partially burnt fuel so the key to reducing smoke is to burn the fuel more completely.

Carbon dioxide and carbon monoxide

Burning fuel normally gives off carbon dioxide (CO₂) when there is plenty of oxygen present. The carbon (C) comes from the fuel and the oxygen (O₂) comes from the air. But, when there’s not enough oxygen present only one oxygen molecule binds with a carbon – forming carbon monoxide (CO).
Carbon dioxide is a greenhouse gas. Increases in carbon dioxide in the atmosphere are likely to be responsible for global warming which may cause climate change.
Carbon monoxide is a poisonous gas. It attaches to our red blood cells better than oxygen - reducing the blood’s ability to carry oxygen around the body. Low exposure to carbon monoxide causes in headaches, dizziness and nausea.

Nitrogen dioxide

Solid-fuel burners (for example, wood burners) are a source of nitrogen oxide (NO). Nitrogen oxide oxidises (oxygen is added) to form nitrogen dioxide (NO₂). Nitrogen dioxide affects people’s health by aggravating asthma and decreasing their lungs' ability to fight infection.

Besides wet wood, there are other materials that are dangerous to burn in your home fire.

When the materials listed below are burnt, they can give off toxic substances that can harm the health of people, animals and the environment. For more information on the effects of these toxic substances, visit the Agency for Toxic Substances and Disease Registry website.

Toxic substances if burnt
- arsenic (from CCA treated wood)
- tin (from LOSP treated wood)
- boron
Potential effects on human health
Short-term exposure:
- sore throat
- lung irritation
Long-term exposure:
- lung damage
- liver and kidney damage
- damage to the central nervous system
- increased risk of cancer
Potential effects on the enviroment
Ash will be contaminated (with arsenic, and may have high levels of copper, chromium, boron or tin). Shouldn't be put on the garden.
Toxic substances if burnt
Depends on type and colour of paint but can give off:
- lead
- cadmium
- barium
- zinc
- copper
- tin
Potential effects on human health
Short-term exposure:
- sore throat
- lung irritation
Long-term exposure:
- lung damage
- liver and kidney damage
- damage to the central nervous system
- increased risk of cancer
Potential effects on the enviroment
Ash is likely to be contaminated with one or more heavy metals.
Toxic substances if burnt
- formaldehyde
Potential effects on human health
Short-term exposure:
- coughing
- headaches
- eye and skin irritation
- asthma attacks
Long-term exposure:
- cancer (suspected)
Potential effects on your fireplace, woodburner or chimney
- creosote in chimney - possible increased risk of chimney fires
Toxic substances if burnt
- dioxins
- furans
Potential effects on human health
Long-term exposure:
- cancer (suspected)
- problems with immune, developmental and reproductive systems
Potential effects on the enviroment
- dioxins can settle on plants, which, if eaten by livestock, contaminate milk and meat
Potential effects on your fireplace, woodburner or chimney
- corrosion of woodburner’s metallic parts (due to high salt content)
Toxic substances if burnt
- VOCs (volatile organic compounds)
- semi-volatile organic compounds (e.g. phenol)
- chlorobenzenes, polyaromatic hydrocarbons, carbonyls (e.g. acetaldehyde, acetone and formaldehyde)
- dioxins
- furans
Potential effects on human health
Long-term exposure:
- cancer (suspected)
- problems with immune, developmental and reproductive systems
Potential effects on the enviroment
- dioxins can settle on plants, which, if eaten by livestock, contaminate milk and meat
Potential effects on your fireplace, woodburner or chimney
- corrosion of woodburner’s metallic parts