Lead and asbestos, chemicals and radon, mould and moisture
Indoor air quality is also damaged by poor choice of building materials, structural risks as well as poor ventilation practices, as follows:
- Moisture build-up, mould and bacterial growth can occur as a result of structural building faults, inadequate heating, insulation or inadequate ventilation. These can increase risks of allergies and asthma.
- Radon is a radioactive gas that emanates from certain rock and soil formations, concentrating in the basement or ground levels of homes, in the absence of inadequate ventilation or evacuation systems. Recent studies on indoor radon in Europe, North America and Asia indicate that lung cancers attributable to radon may range from 3–14%.
- Asbestos fibres, used in roofing and insulation, have significant carcinogenic effects upon exposed building inhabitants and construction workers. Asbestos use is still unregulated and prevalent in many developing countries.
- Lead, still common in certain paints and pipe products in developing countries, has toxic effects and exposure to inhaled or ingested lead dust from has been linked to impaired childhood cognitive development.
- Volatile organic compounds (VOC), including formaldehyde, may be emitted slowly from indoor building materials, furniture, paints and carpets. VOCs also may be released by smoking and detergent, or drift in from attached garages or outdoor sources. These can contribute to acute conditions (e.g. poisonings) as well as cancers and asthma. Compact fluorescent lights as well as thermostats commonly contain mercury and thus must be handled with care to avoid exposures, particularly when broken.
Risks of indoor air pollutants can be lowered by adequate natural ventilation as well as through the use of healthier building materials, including replacement or phasing out of hazardous building substances wherever possible.