Passive Design

Poor indoor air quality (IAQ) has been linked to a range of symptoms such as headaches, sinus congestion, dizziness, nausea, and irritations of the eye, nose and throat.

Sources of poor air quality

The main sources of pollution from construction materials and methods, and appliances in houses are from:

• new materials containing urea-formaldehyde (such as particleboard, carpets, upholstery fabrics, sealants) and volatile organic compounds (such as vinyl and carpets, adhesives, polyurethanes, epoxies, paints and solvents, sealants and some cleaning products)
• poor quality detailing/construction that results in buildings that leak – mould, bacteria and other bio-contaminants can thrive in moist conditions (see controlling humidity)
• combustion appliances that burn natural gas, oil and wood.

Urea-formaldehyde and volatile organic compounds (VOCs) are released as gases at room temperature into the internal environment. The term ’organic‘ indicates that the compounds contain carbon.

Other sources of indoor pollutants are:

• occupants – eg moisture from breath and from activities such as cooking, washing and bathing
• smoking
• dust and pollution from the surrounding environment

For more detailed information about common pollutants and their health impacts, see common airborne pollutants.

Controlling air quality

To reduce the threat to health from airborne pollution, designers can:

• specify materials that are free of or low in volatile organic compounds
• reduce the need for combustion appliances
• design ventilation to reduce concentrations of airborne pollutants and moisture (this is necessary all year round)
• isolate or contain pollutants where possible (for example, by sealing materials that contain VOCs).