indoor air quality

Good indoor air quality (IAQ) is vitally important for good health.

The quality of air is affected by a range of gases, particulate materials (dust etc), moulds and spores, bacteria and viruses. It has been shown that the indoor environment can be up to ten times more polluted than the outdoor environment. We spend about 80% of our lives indoors, in that polluted environment. Eliminating these hazardous elements from your environment will improve indoor air quality.

Where do these hazardous elements originate?

Building materials generate many volatile organic compounds (VOCs) such as carbon monoxide, formaldehyde, benzene and many more.

Furniture manufacture uses glues and varnishes, most of which are solvent based. These solvents give off harmful fumes.

Small water leaks and moisture ingress can create ideal environments for moulds and similar spore-carriers to grow. These microscopic spores can be breathed in and infect lungs.

Bacteria and viruses originate in all sorts of strange environments. Even the goods that you buy in the supermarket can be carrying bugs that are harmful.

Natural ventilation, will allow many of the harmful gaseous elements to be diluted over time. Cracking a skylight will quickly allow warmer air to escape, drawing fresh air in. This always works well in the kitchen where heats is generated. Opening the skylight allows the hot air to rise creating a thermosiphon effect. Controlling the source of fresh air is the main focus so that no particulates can be brought into the environment. This involves filtering the incoming air. With the thermosiphon effect, air will flow in through the filter but we normally need a lot more than can be extracted by one skylight. So with filtration comes a requirement for a fan to move the air effectively.

Eco-friendly building methods can help to reduce the effects of polluting substances and improve indoor air quality by utilising materials which do not use solvents, plastics and other harmful chemical pollutants such as formaldehyde, trichloroethylene and benzene. These volatile organic compounds (VOCs) are carried in the air after having evaporated out of paints and building materials.

Mould, mildew, dust mites and other allergens are biological indoor air pollutants that can also contribute to sick building syndrome, aggravate allergies, and deteriorate building components. The effect of these biological pollutants can be avoided by using materials such as bamboo, ceramic and porcelain tile and linoleum rather than carpet and other porous materials. Any water leaks or damp spots must be attended to immediately – mould thrives in warm and damp areas.

Chemically treated carpets, adhesives, and backings can emit numerous chemicals. Where carpet is used, obtain test data prior to purchase and avoid carpets with topical chemical treatments. Consider airing-out the carpet prior to installation and use of a zeolite mineral wash to help absorb odours. Use low-VOC adhesives for installation. Consistent maintenance is also important. A better plan is to avoid carpets completely.

NASA, in their Clean Air Study, recommends using an air-filtering plant for every 10 square metres of floor space to assist in removing chemical pollutants carried in the air. Interestingly, many of South Africa's indigenous plants are suitable as houseplants for this very purpose.

The list includes:

Of course, placing plants doesn’t really help if your house is not very airtight. It’s a good idea to ensure that windows and doors are well sealed when closed. This will help to keep the good air in but also help to retain heat during winter. Strategically located vents will allow specific areas to be ventilated as and when required.




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