OHS Air Quality Standards (Indoor Air)

Indoor air quality has become an important health and safety concern.

Common issues associated with IAQ include:

• Improper or inadequately maintained heating and ventilation systems.
• Contamination by construction materials, glues, fibreglass, particle boards, paints, chemicals, etc.
• Increase in number of building occupants and time spent indoors.

IAQ problems result from interactions between building materials and furnishing, activities within the building, climate, and building occupants. IAQ problems may arise from one or more of the following causes:

• Indoor environment - inadequate temperature, humidity, poor air circulation, ventilation system issues.
• Indoor air contaminants - chemicals, dusts, moulds or fungi, bacteria, gases, vapours, odours.
• Insufficient outdoor air intake.

Here are examples of common indoor air contaminants and their main sources:

• Carbon dioxide (CO₂), tobacco smoke, perfume, body odours – from building occupants.
• Dust, fibreglass, asbestos, gases, including formaldehyde – from building materials.
• Toxic vapours, volatile organic compounds (VOCs) – from workplace cleansers, solvents, pesticides, disinfectants, glues.
• Gases, vapours, odours – off-gas emissions from furniture, carpets, and paints.
• Dust mites – from carpets, fabric, foam chair cushions.
• Microbial contaminants, fungi, moulds, bacteria – from damp areas, stagnant water and condensate pans.
• Ozone – from photocopiers, electric motors, electrostatic air cleaners.

It is common for people to report one or more of the following symptoms:

• Dryness and irritation of the eyes, nose, throat, and skin
• Headache
• Fatigue
• Shortness of breath
• Hypersensitivity and allergies
• Sinus congestion
• Coughing and sneezing
• Dizziness
• Nausea

People generally notice their symptoms after several hours at work and feel better after they have left the building or when they have been away from the building for a weekend or a vacation.

Many of these symptoms may also be caused by other health conditions including common colds or the flu, and are not necessarily due to poor IAQ. This fact can make identifying and resolving IAQ problems more difficult.

Occupants of buildings with poor IAQ report a wide range of health problems which are often called Sick Building Syndrome (SBS) or Tight Building Syndrome (TBS), Building-Related Illness (BRI) and Multiple Chemical Sensitivities (MCS).

The term sick building syndrome (SBS) is used to describe cases in which building occupants experience adverse health effects that are apparently linked to the time they spend in the building. However, no specific illnesses or cause can be identified.

Building-Related Illness (BRI) refers to less frequent (but often more serious) cases of people becoming ill after being in a specific building at a certain time. In these cases, there is usually a similar set of clinical symptoms experienced by the people and a clear cause can often be found upon investigation. Legionnaires Disease is an example of BRI caused by bacteria which can contaminate a building's air conditioning system.

A certain percentage of workers may react to a number of chemicals in indoor air, each of which may occur at very low concentrations. Such reactions are known as multiple chemical sensitivities (MCS). Several medical organizations have not recognized multiple chemical sensitivities. However, medical opinion is divided, and further research is needed.

When there is a problem with IAQ, people may experience various health conditions that are listed above. Since many of the symptoms are very similar to what we feel like when coming down with a cold or the flu (influenza), it is often difficult to say for sure if indoor air is the cause of the symptoms.

However, it would be prudent to investigate IAQ if people develop these symptoms within a few hours of starting the workday and feel better after leaving the building, or after a weekend or vacation. In addition, if many people report similar symptoms, or if all of the people reporting symptoms work in the same area of a building, air quality should be suspected.

SOURCE:  Canadian Centre for Occupational Health. (2020, April 10). Indoor Air Quality - General : OSH Answers. Retrieved from https://www.ccohs.ca/oshanswers/chemicals/iaq_intro.html