The most common causes of IAQ problems in buildings are:

• Not enough ventilation, lack of fresh outdoor air or contaminated air being brought into the building
• Poor upkeep of ventilation, heating and air-conditioning systems
• Dampness and moisture damage due to leaks, flooding or high humidity
• Occupant activities, such as construction or remodelling
• Indoor and outdoor contaminated air

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This is an abbreviation for Heating, Ventilation and Air Conditioning (and HVAC-R, where the R stands for Refrigeration). It covers all air conditioning from high rise buildings through to residential systems. It is across all areas of modern life through retail, commercial and industrial applications. It includes a variety of equipment for heat transfer & air movement to facilitate the supply of clean, temperature controlled air to an occupied space.

The Queensland Work Health and Safety Act 2011 clearly defines the duties to ensure the health and safety of workers. This includes the management of risks, the provision and maintenance of safe plant and structures. It makes reference to the use of Codes of Practice which includes “Managing the work environment and facilities”. This sets out that a person conducting a business or undertaking has the responsibility to provide a clean safe work environment. This includes Air Quality, Temperature and any other issue that may affect a workers health or safety. There are several Australian Standards including AS/NZS 3666 (Parts 1, 2, 3 & 4), AS 1668 and AS 1851 which are used as references in this area as well as the AIRAH Best Practice Guideline on HVAC Hygiene.

Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Understanding and controlling common pollutants indoors can help reduce your risk of indoor health concerns.

Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.

Inhaling mould spores and particles or touching mould patches may cause allergic reactions to mould-sensitised individuals. Symptoms other than allergic and irritant types are not common. There is no threshold for the health effects of mould, but it is advisable to remove all visible mould growth and apply remediation measures irrespective of the extent of mould growth.

By definition Mould is a fungi with a mycelial (filamentous) type of growth. While they are present in outdoor air they are of a greater concern in indoor environments with the potential to affect human health. Mould needs 4 items to grow – Moisture, a suitable Temperature range, Nutrients and Spores. The spores occur naturally in the ambient air. The other 3 items are all present in a HVAC system.

HEPA is a type of pleated mechanical air filter. It is an acronym for "high efficiency particulate air [filter]" (as officially defined by the U.S. Dept. of Energy). This type of air filter can theoretically remove at least 99.97% of dust, pollen, mould, bacteria, and any airborne particles with a size of 0.3 microns (µm). The diameter specification of 0.3 microns responds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even higher efficiency. Using the worst case particle size results in the worst case efficiency rating (i.e. 99.97% or better for all particle sizes).

All air cleaners require periodic cleaning and filter replacement to function properly.

Volatile organic compounds are compounds that have a high vapour pressure and low water solubility. Many VOCs are human-made chemicals that are used and produced in the manufacture of paints, pharmaceuticals, and refrigerants. VOCs typically are industrial solvents, such as trichloroethylene; fuel oxygenates, such as methyl tert-butyl ether (MTBE); or by-products produced by chlorination in water treatment, such as chloroform. VOCs are often components of petroleum fuels, hydraulic fluids, paint thinners, and dry cleaning agents. VOCs are common ground-water contaminants.

Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands. Examples include: paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions.

Organic chemicals are widely used as ingredients in household products. Paints, varnishes, and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing, and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while you are using them, and, to some degree, when they are stored.

EPA's Total Exposure Assessment Methodology (TEAM) studies found levels of about a dozen common organic pollutants to be 2 to 5 times higher inside built environments than outside, regardless of whether located in rural or highly industrial areas. Additional TEAM studies indicate that while people are using products containing organic chemicals, they can expose themselves and others to very high pollutant levels, and elevated concentrations can persist in the air long after the activity is completed.

The Aeroseal process seals duct leaks from the inside, using small sealant particles that deposit at the leaks without coating the interior of the duct system. This is accomplished by pressurising the duct system with a fog of sealant particles sized to stay suspended in the air until they try to exit the duct system. By blocking all of the intentional openings in the duct system (i.e. diffusers or grilles), all of the sealant-laden air is forced out through to the leaks. As the duct pressure causes the particles to accelerate through the leaks, they stick to the edge and build upon each other until the leaks are sealed. By constantly monitoring the duct pressure and flow, the process-control computer calculates and the displays the remaining leakage in real time. When the sealing is finished, a complete minute-by-minute record of the process is printed, stored on the local computer, and then uploaded over the internet for archival on the Aeroseal server.

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The C wavelength of the UV spectrum targets the DNA of microorganisms, destroying their cells and making replication impossible. Directed at a cooling coil or drain pan, UVC energy destroys surface biofilm, a gluey matrix of microorganisms (bacteria, fungi, debris, et al.) that grows in the presence of moisture. Biofilm is prevalent in HVAC systems and leads to a host of indoor air quality (IAQ) and HVAC operational problems that are sometimes mistakenly attributed solely to mould. UVC also destroys airborne viruses and bacteria that circulate through an HVAC system.

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