Current issues
Air cleaning devices
Air cleaning devices are available in Australia, especially as stand-alone
devices for rooms, and are often marketed with little evidence to support their
effectiveness. Such devices need to be able to demonstrate two key factors:
- That they can remove a range of pollutants from air, both gaseous and
particulate, with a level of efficiency that is known and maintained over
time.
- That they actually treat a sufficiently large volume of room air to
cause a significant reduction in pollutant levels. For example, a
high-efficiency device will need to treat more than four room volumes per
hour if it is to reduce pollutant levels to about 20 per cent.
Gas heaters
Manufacturers of unflued gas heaters have been reducing nitrogen dioxide
emissions for several years, producing ‘low-nitrogen oxides’ heaters for the
Australian market. However, even these heaters will lead to nitrogen dioxide
concentrations in buildings which are above health-based air-quality guidelines
under circumstances where:
- the building ventilation rate is low, or
- the heating capacity of the heater is high relative to the building
volume.
Additionally, some of these ‘low-nitrogen oxides’ heaters have been found to
emit formaldehyde as a product of inefficient gas combustion.
Building materials
Wood-based panels use several types of resin in their manufacture which can
emit formaldehyde gas for years after manufacture. Homeowners should consider
keeping several windows open for the first six months after construction or
renovation to counter the emissions of formaldehyde and VOCs from new materials.
Many countries now specify VOC emission limits for building materials and
contents resulting in the availability of several hundred low-VOC products.
However, this strategy has yet to be instigated by Australian industry.
