Looks like we're going to be inside our homes for a while. Here are some facts about indoor air and wool carpet, it may come in handy on your next carpet sale. We are now spending around 90% of our lives indoors and indoor air pollution is now of greater importance to human health than outdoor air pollution. The effects of indoor air pollution on us, whether at home or the workplace, are varied but can include irritation of the eyes, nose and throat, respiratory illness, headaches, dizziness, and fatigue. Indoor air pollution occurs when harmful gases and or particles are released into the air of an interior environment. When the air circulation or exchange is poor, these contaminants can build up to potentially harmful levels.
There are a variety of sources of indoor air pollution such as:
- Interior furnishings and household chemicals that can release Volatile Organic Compounds (VOCs).
- Heating systems and home appliances
- Tobacco smoke
- Building materials
- Allergens from pets, house-dust mites, fungi, bacteria, pollens, etc.
WHAT ARE VOLATIVE ORGANIC COMPOUNDS (VOC)?
Many new products have a characteristic odor - such as the smell of a new car, fresh paint, new carpet, etc. This odor is due to the release of Volatile Organic Compounds (VOC's). VOCs are gases and vapors that typically dissipate within a short period.
HOW DOES WOOL CARPET HELP WITH VOC'S AND INDOOR AIR POLLUTION?
It is important to note that this study was done in Europe so the measurements are metric. Interior furnishings and textiles can act as 'sinks' to absorb certain particulate and gaseous atmospheric pollutants from the indoor environment. Because of their nature and materials used in their construction, carpets present a much larger area for gas absorption than other interior fixtures and furnishings. 1m
2 of painted wall represents little more than 1m
2 of absorbing surface, whereas approximately 1m
2 of carpet containing 1000g of wool 35μm in diameter in the surface pile presents a fiber surface of at least 100m
2. Carpets therefore have the potential to make a greater contribution to the removal of indoor air pollutants than many other interior products.
DOES WOOL CARPET REMOVE INDOOR AIR POLLUTANTS MORE EFFECTIVELY THAN SYNTHETIC CARPET?
Three common gaseous indoor air pollutants with known adverse health effects on humans are Nitrogen dioxide (NO
2), sulphur dioxide (SO
2) and formaldehyde (HCOH) - all of which are removed
NO2 removal rates for various residential materials (Spicer et al 1986).
Nitrogen Dioxide Absorption
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Nitrogen Dioxide Absorption |
Work has been done to determine NO
2 removal from indoor air with 35 types of building materials and furnishings found that the highest removal rates were for wallboard, cement block, wool carpet, and brick. Acrylic, polyester and nylon carpets had NO
2 removal rates under one third those of 100% wool carpet.
Formaldehyde Absorption
Carpet has also been shown to be effective in absorbing formaldehyde. Wool carpets begin to absorb formaldehyde as soon as it is introduced to their surroundings. Wool carpets have been shown to reduce levels of formaldehyde from 420ppm to 0.5ppm in four hours. In the same study, nylon carpets exhibited a slower rate of absorption, reducing 420ppm to 80ppm in four hours.
Sulphur Dioxide Absorption
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Sulfer Dioxide Absorption |
When wool, nylon, cotton, and viscose rayon fibers are exposed to sulphur dioxide it has been shown nylon became saturated quite quickly; rayon becomes saturated within an hour, but wool and cotton continue to absorb sulphur dioxide after 1 hour.
Pollutant Re-emission
It has been shown that re-emission of NO
2
from wool carpet and cement block is negligible, even with moderate increases in temperature or relative humidity. Previous work has shown that SO
2
and formaldehyde are not readily re-emitted by wool carpet. The complex chemistry of the wool fiber enables it to bind pollutant gases chemically in its structure and it has been estimated that wool carpets can continue purifying indoor air for up to 30 years.
Studies available on request
