Air Quality Testing

Air Quality Testing and Other Challenges to Building Evaluations


Air Quality Testing: CAUTION

Air quality testing is one tool for determining possible contaminants in an indoor environmentWhen a school is suspected of having Indoor Air Quality (IAQ) problems, building occupants or the public often demand “testing” and want to see the results. Sometimes they lose trust in the authorities when the tests they demanded come back inconclusive or negative. Building operators also may be left not knowing what to do, having done what seemed to be a reliable test, and finding little or nothing to indicate the nature of the problem. Trust between people dips lower.

It is usually best to ask for a building evaluation. Professionals in building environments rely on much more than testing to evaluate what is usually a complex situation. They may or may not require testing. Air quality testing is one tool for determining possible contaminants in an indoor environment. Common tests can include CO2 (Carbon Dioxide), CO (Carbon Monoxide), dust, mould, asbestos, particulates, Total Volatile Organic Compounds (TVOC), and individual VOCs such as Formaldehyde. For moulds, tests try to determine the extent of mould infestation and the varieties present. Testing is not as exact a science as we would like, however. Tests need to be used with caution and the results need interpretation by experts. Here are examples:

Example 1: Mould

An air quality test that did not find abnormal mould varieties or levels is not a guarantee that mould is not the problem. If you can see or smell mould or mustiness, then you have mould and it needs to be removed. It is also important to know that bits of dead mould that float in the breathing space can be harmful even though they don’t show up on test results. Common mould tests measure only live spores. If the colony is in a dormant part of the life cycle live spores will not be in production at the time of the test, and cannot be measured. If the moisture levels are down, or if air circulation is up, or any of several other factors are present or absent, the tests may not find mould spores even though mould contamination may still be present. This is an oversimplification, but a very important point. Again, it tends to be better to ask for an evaluation by building environment specialists rather than just to ask for testing. These experts will know whether testing is likely to be helpful, and what action is needed.

Indoor mould growth, even the more benign varieties, can harm health. See

 Example 2: TVOCs

Expensive errors can be made by well-intentioned but inexperienced peopleIn a new high school that opened in September 2007, test results for Total Volatile Organic Compounds (TVOC) were “0,” yet anyone entering the building could clearly smell building chemicals. Some areas were worse than others. Many teachers and students reported headaches, brain fog, fatigue and other symptoms during the first few weeks of classes. These symptoms passed when occupants left the school. Several months later, several teachers and students reported that their health had been harmed to the point where they could no longer work. At our last count in Fall 2008, 15 teachers and three students reported longer term effects. We do not have access to school health reports, so it is reasonable to assume there are more. Yet, TVOC test results reported no air contamination. The human body is often more sensitive to the presence of chemical contaminants than measuring equipment. However, aside from this, there are several reasons for possible equipment failure, including calibration, timing, location, skill of the operator, and more.

Attempts by building administrators and maintenance staff to solve problems better suited to professional evaluation often fall short, increase the problems, and can be very expensive.

It is not common for building staff or even maintenance staff to have the knowledge or skills required to solve all building related IAQ issues. Expensive errors can be made by well-intentioned but inexperienced people making evaluation and remediation decisions.

There are many examples. In one old high school that was finally replaced in 2003, over a million dollars had been spent on attempts to solve IAQ problems by staff without enough training. The students were moved into half the school while walls were gutted in the other half, mould removed, and walls replaced. Then they all moved into that side and the process was repeated. Things improved for a while, but the following year all the health complaints began again. It was learned that the windows, a source of leaks, had not been replaced in the renovation, and mould had re-grown inside walls. Later, when a new and extensive exhaust-only ventilation system was installed in another attempt at a solution, the mould from inside the wall cavities was drawn into the breathing space, thus making things worse.

IAQ standards are designed for healthy adult males in industry settingsRelying on industry standards for allowable levels of indoor pollution and daily exposure rates fails to protect vulnerable staff, including pregnant women (many pollutants cross the placenta), the developing bodies of children, those with asthma and other health issues, and those with environmental sensitivities. IAQ standards are designed for healthy adult males in industry settings. Workers who find industry standards do not protect them (for example, pesticide sprayers or factory workers) may choose to change jobs, but children must stay in school. Even the residential standards for emissions are sometimes not enough protection.

Methods and materials used in repair work have potential to create new problems.

It is important to choose low-emission, less-toxic building materials and to use isolation techniques such as timing, barriers, and building flush-out procedures to protect occupants. For bigger projects, it is best to move occupants to another site until it is safe to return.

What Works Better

A coordinated team approach

IAQ problems can be simple or can be complex. For evaluation, a coordinated team approach tends to work better because of the interaction between various building systems. Ventilation system issues and indoor mould growth, for example, can interact, yet may need separate experts for evaluation and to make recommendations.

Controls vs standards.

In schools, using “controls” is a good alternative to using workplace industrial exposure “standards”. Controls include choosing low-emission/less-toxic materials, practicing good isolation techniques, scheduling cleaning or construction work for off-hours, and generally removing or avoiding potential problems before they happen. Practicing these controls instead of relying on testing or industry standards can avoid many problems. If, for example, a potentially harmful material is not present in the chosen building materials, then it is simply not a risk. If it is not present, there is no doubt and no risk to health.

Choosing capable evaluators

Many businesses claim expertise in solving building IAQ problems, but there is no certification program to standardize or prove claims. CMHC has a program for housing evaluators and the University of Calgary Building Sciences Department has graduates who have these skills. In general, companies are gradually getting better at this, but there are still marked weaknesses.

In Nova Scotia, the Department of Education staff have become very good at working with available professionals to identify school building problems.

Seek occupant input

Useful clues and information can come from occupants who can report where, when, and how they experience building-related symptoms. The QUEESI test is a scientifically proven tool based on body symptoms that can help identify building IAQ deficiencies.

A transparent approach to solving possible building problems reduces fears and mistrust among staff, students, parents, communities, and authorities. Keep the community involved and informed.

Useful background:

Canada’s Tools for Schools IAQ Action Kit:

CASLE’s streamlined checklists for use with this kit can be found at

EPA Indoor Air Quality (IAQ) Tools for Schools (TfS) Evaluation

Minnesota Department of Health: School Related Programs and Initiatives

Healthy Schools Network: Parents’ Guide to Indoor Air Quality