What is Indoor Air Quality?
The National Health and Medical Research Council NHMRC defines indoor air as any non-industrial indoor space where a person spends a period of an hour or more in any day. This can include the office, classroom, motor vehicle, shopping centre, hospital and home. Historically, indoor air quality has been addressed to varying degrees by the health, occupational health and safety and environment agencies of government. Such agencies have also drawn on advice from the NHMRC.
It is important to make certain that our indoor air quality is of a sufficient standard to ensure the adequate protection of human health and well being. This is particularly the case as Australians may spend 90% or more of their time indoors. Further, it is generally accepted that poor indoor air quality can result in health problems, which may carry a substantial cost burden. The CSIRO estimates that the cost of poor internal air quality in Australia may be as high as $12 billion per year (Brown 1998b).
Despite the long periods we spend indoors, relatively little research has been done on the quality of air in our homes, schools, recreational buildings, restaurants, public buildings and offices or inside cars. In recent years, comparative risk studies performed by the US EPA and its Science Advisory Board have consistently ranked indoor air pollution among the top five environmental risks to public health.
What Causes Indoor Air Problems?
Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems in homes. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and humidity levels can also increase concentrations of some pollutants.
What are the Common Sources of Pollutants?
There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.
The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are. In some cases, factors such as how old the source is and whether it is properly maintained are significant. For example, an improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly adjusted.
Some sources, such as building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently. These include smoking, the use of unvented or malfunctioning stoves, furnaces, or space heaters, the use of solvents in cleaning and hobby activities, the use of paint strippers in redecorating activities, and the use of cleaning products and pesticides in house-keeping. High pollutant concentrations can remain in the air for long periods after some of these activities.
For more information regarding indoor air quality, please visit Queensland and NSW Laboratory