Generally speaking, most occupants in a building take good indoor air quality (IAQ) for granted. However, when IAQ becomes an issue, building managers might quickly be confronted with complaints and pressure to resolve them.

Not only can poor indoor air quality affect occupant comfort, it can also be associated with health issues, ranging from mild symptoms such as sneezing or drowsiness, to much more severe situations such as headache, dizziness and elevated risk of chronic diseases. In extreme (but rare) cases, contaminated indoor air, containing high carbon monoxide levels, can lead to acute poisoning and possible death. Most occupants and building owners don’t notice the quality of the air when there is a sufficient amount of outdoor air, the air is distributed adequately, and the recirculated air is handled properly.

The Canadian Committee on Indoor Air Quality (CCIAQ) considers the topic of indoor air quality in buildings very important for both public safety and comfort. The CCIAQ is a group of professionals from various organizations across Canada ( whose mission is to improve indoor air quality in buildings and ultimately the health of occupants ( To help building managers and occupants, the CCIAQ has designed a series of modules to help building owners, operators, and managers provide the building with adequate indoor air quality.

Presented below are five common IAQ issues that building managers can be confronted with.

1. Complaints about poor ventilation or air quality
When occupants complain about odours, stale air, dizziness, difficulty in concentrating, fatigue, sometimes even difficulties breathing, a potential culprit is improper ventilation and air circulation either at the workstation, office, or the overall building level in general. The indoor air quality of the building might suffer when a heating ventilation and air conditioning (HVAC) system is undersized or is not operating optimally for the needs of the building or the number of occupants. This could lead to contaminants, or gases such as carbon dioxide, from indoor sources or human activities building up if the rate of outdoor air exchange throughout the building is not sufficient. Module 5–Hygienic Operation of Air-Handling Systems, provides some insights on HVAC systems.

2. Mould complaints
Building managers often have to deal with complaints related to mould on surfaces or how mould is affecting occupant health. Human reactions in indoor environments and being able to trace causes of health symptoms can be difficult and takes diligent detective work. This process can be frustrating to building managers, as mould growth in buildings can be difficult to trace. Mould can grow on nearly any building material, if sufficient water and environmental conditions persist over long enough periods of time. Broken pipes, water leakage, minor roof leaks, water condensation in dark places such as air ducts and wall cavities, may produce mould and release spores if the environment is moist and left undisturbed. If you are concerned about health issues related to mould, please see Module 10-Management Strategies for Moulds and Microbiologic Agents. Further assistance can also be obtained from a mould abatement specialist.

3. Odour problems
Like mould, odour issues are common and may be difficult to trace. When investigating the complaint, building managers should follow appropriate procedures and document interviews and findings. Each complainant should be interviewed individually. Often a walkthrough of the area is the first step. Module 4–Recognizing and Addressing IAQ Problems and Module 7-Communicating With Tenant Organizations and Individual Occupants cover how to address IAQ issues and communicate with occupants. Module 6-Scent Free Buildings and Module 3-Custodial Activities, Maintenance, Repair and Renovation also provide information which can aid in reducing odour complaints.

4. Temperature or humidity control
The temperature and humidity levels of a building can create discomfort and affect occupant well-being. Occupants may feel too hot, too cold, too drafty, or may raise concerns about the air being too dry or too damp; it can be challenging for building managers to please everyone. Overall, the building should provide comfort for the majority of occupants, and the temperature and relative humidity (ideally between 30-50%) should fall within acceptable ranges. If many occupants are telling the building manager that the building is too hot or too cold, then that is usually indicative that the HVAC system needs attention. This can also happen more in shoulder seasons like spring and fall when outdoor temperature changes can be happening faster than the HVAC system has been programmed to react to.
In the winter if there is no humidification system, the indoor air can become very dry and increase the risk of static discharge. Excessive humidity indoors can increase the chances of mould growth and a host of problems that affect the IAQ of the building.

5. Construction or remodeling activities
When buildings are undergoing renovations, the building manager should ensure that the materials used in an enclosed space are non-toxic and won’t over time emit compounds or chemicals that affect the building occupants. Depending on the type of renovation, and the work being done, it may need to be scheduled when all occupants are out of the building.
Oftentimes construction dust, off-gassing from carpets or new furniture, and odours from such activities as painting can affect occupants and have negative health effects. Module 2–Volatile Organic Compounds (VOC) Sampling Methods and Strategies provides some information about the sources of VOCs. Effects from this kind of work can be minimized if contained and of a short duration, or it can have lasting implications for a lengthy renovation project if not adequately planned for. Preventative measures to protect occupants, such as sealing off the area under construction, temporarily increasing the amount of air being exchanged, adding extra fans or exhaust fans ducted to the outdoors, proper choice of building and renovating materials, quickly disposing of debris, and careful clean-up of all renovation dust can greatly improve the situation.

To summarize, many indoor air quality issues in buildings can be avoided by controlling sources of contaminants (e.g. emissions of VOCs), proper planning, and by maintaining the HVAC systems. Creating a baseline building IAQ profile may be helpful in addressing IAQ issues or in planning for renovations or building modifications.

CCIAQ’s Module 8 – Creating a Building IAQ Profile describes how to do this.
Being proactive and responsive to IAQ issues will ensure healthy and comfortable environments for building occupants. CCIAQ modules are designed to help you meet that goal.

Check out the full suite of CCIAQ guidance documents available under the IAQ Guides menu option on this website.