Indoor Air

Indoor Air

Indoor Environmental Quality

It is generally recognised that Australians spend 90% or more of their time indoors either relaxing or working. Until recently relatively little research has been done on the quality of air in our homes, offices, schools, recreational buildings, restaurants, public buildings or even inside cars.

Less than acceptable indoor air quality can result in significant adverse impacts on our health and environment. Furthermore these impacts carry significant cost burdens to the economy. The C.S.I.R.O. estimates that the cost of less than acceptable indoor air quality in Australia may be as high as $12 billion per year. 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.

Definition of Indoor Air

The National Health and Medical Research Council (NHMRC) define indoor air as; “Air within a building occupied for at least one hour by people of varying states of health”

This can include the office, classroom, transport facility, shopping centre, hospital and home. Indoor air quality can be defined as the totality of attributes of indoor air that affect a person’s health and wellbeing.

As commercial buildings and dwellings have become better sealed from the external environment, pollutants being released from indoor sources are being found at higher concentrations.

Indoor air quality can be adversely affected by other pollutants such as fungi, microbial contamination, house dust mites, particulates and air toxics such as formaldehyde and other volatile organic compounds.

Resolving indoor air quality problems

Investigating and resolving indoor air quality problems can be complex.

However identifying the likely cause and controlling it should minimise health and comfort concerns and maintain or increase productivity. The Building Manager may choose to employ a Mechanical Services contractor who has an in-house specialist in this field or an Occupational Hygienist to conduct the indoor air quality investigation.

What we do

A proper investigation of indoor air quality generally involves:

• A walk through inspection to gather information on the issues detailed above.
• Inspection of possible problem areas and consultation with building owners.
• Review of any documentation available on the above issues.
• Consultation with the person managing the maintenance strategies and control of the H.V.A.C. systems.
• Taking measurements of air movement, temperature, humidity and carbon dioxide.

Monitoring for specific airborne contaminants is not usually helpful as they are commonly present at levels below workplace exposure standards. Health or comfort symptoms are more likely to be caused by a combination of contaminants than from a high level of one specific contaminant.

Carbon dioxide is the exception as it is an indicator of the adequacy of ventilation for the number of occupants in a building.

Following the investigation, the investigator may form a theory or hypothesis about the cause of the problems. This should be tested and verified by implementing corrective action procedures and then carrying out further inspections and consultation to see whether the problem has been resolved. If the investigator has not been able to identify a possible cause of the problem a more detailed inspection of the building and its air handling systems may be required.

The Dirt and Bugs are Spreading. If the grille in this picture looks like it does then chances are the evaporator and return air duct look the same way.