Indoor Air Quality (IAQ) has been studied since the introduction of mechanical ventilation in commercial buildings, in particular the amount of fresh air requirement. During the energy crisis of the 1970s buildings were designed to be airtight to conserve energy. The sealed buildings lead to lack of fresh air, buildup of air pollutants from the building material, and thermal discomfort. The accumulation of these contaminants and poor ventilation can cause adverse health effects among building occupants. Poor IAQ caused a rise in reported cases of "sick building syndrome" and building-related illnesses. Since we spend majority of our time indoors whether at home or in the office, maintaining good IAQ has become critical from health standpoint.
Some of the most common pollutants and their sources indoors are as follows:
See instructions on how to use the calculator.
Air Pollutants
| Pollutant | Major Emission Sources |
|---|---|
| Allergens | House dust, domestic animals, insects |
| Asbestos | Fire retardant materials, insulation |
| Carbon dioxide | Metabolic activity, combustion activities, motor vehicles in garages |
| Carbon monoxide | Fuel burning, boilers, stoves, gas or kerosene heaters, tobacco smoke |
| Formaldehyde | Particleboard, insulation, furnishings |
| Micro-organisms | People, animals, plants, air conditioning systems |
| Nitrogen dioxide | Outdoor air, fuel burning, motor vehicles in garages |
| Organic substances | Adhesives, solvents, building materials, volatilisation, combustion, paints, tobacco smoke |
| Ozone | Photochemical reactions |
| Particles | Re-suspension, tobacco smoke, combustion products |
| Polycyclic aromatic hydrocarbons | Fuel combustion, tobacco smoke |
| Ozone | Photochemical reactions |
| Pollens | Outdoor air, trees, grass, weeds, plants |
| Radon | Soil, building construction materials (concrete, stone) |
| Fungal spores | Soil, plants, food stuffs, internal surfaces |
| Sulphur dioxide | Outdoor air, fuel combustion |
Source: A. P. Jones. (1999). Indoor Air Quality and Health. Atmospheric Environment, 33: 4535-4564.
An Excel-based tool to assist you in determining the adequacy of the ventilation in your workspace. It can be used to evaluate classrooms, single offices and small meeting rooms.
Parameters for thermal and acoustic environment, air quality and lighting.
Assesses the air quality in your workplace and get options for taking action on any air quality issues
How it can affect your health
OHCOW has experienced in its numerous IAQ studies at variety of different workplaces (Indoors) that a poor indoor air quality can be associated with headaches, fatigue, respiratory issues like asthma and allergies and respiratory, eye, and nasal irritation, dry skin and eyes etc. by the office occupants.
Investigating IAQ complaints
To investigate adverse health complaints an Occupational hygienist usually measures IAQ parameters such as temperature, relative humidity, carbon dioxide, carbon monoxide, TVOCs, particulate matter with a size fraction of 2.5 micron or sub-micron level, mould spores (viable or non-viable). In most cases it is difficult to link one parameter to a particular adverse health effect unless it is obvious. However, bringing the IAQ parameters within the recommended guidelines such as ASHRAE and Health Canada IAQ guidelines usually results in resolving the health complaints.
From occupational health standpoint, it is important to first survey the adverse health effects reported by the occupants and then strategize the IAQ sampling based on the survey summary. However, surveying the adverse health effects using a questionnaire is not always possible. In this case an occupational hygienist can also collect the health complaints information from the JHSC members or the office occupants during the walk through survey.
Sick Building Syndrome
In some cases, building occupants complaint of unrelated symptoms which do not point towards a particular IAQ parameter. This situation is called Sick Building Syndrome (SBS) and the symptoms can range from vague to subjective health complaints.
Surveying the building occupants using a questionnaire to find common threads on the type of symptoms, temporal relationship of symptoms with building, and severity of symptoms may help to find the cause of the adverse health effects along with IAQ sampling. Alternatively, one can modify different IAQ parameters and see if they improve the health condition or not (hit and trial approach), especially in SBS cases where there is no commonality among occupant’s responses (insert).
What about regulations?
Unfortunately there are no regulations specific to IAQ, however, this is an employer’s responsibility to provide healthy and safe workplace to its employees under general duty clause, section 25(2)(h) of the Occupational Health and Safety Act which states that an employer has to take every precaution reasonable in the circumstances for the protection of workers.
OHCOW Resource
VIDEO: A Brief Overview of Indoor Air Quality Challenges
OHCOW Occupational Hygienists James Miuccio and Sonya Lal give a presentation on how indoor air is affected by pollutants and thermal conditions.
Why Indoor Air Quality Matters
The air we breathe indoors has a direct impact on our health, comfort, and productivity. Since most people spend up to 90% of their time inside homes, offices, and other buildings, maintaining clean and healthy air is essential. Poor indoor air quality can contribute to headaches, fatigue, respiratory issues, and long-term health concerns such as asthma and allergies. Thermal comfort which is influenced by temperature and relative humidity have reported to increase the concentration and reduce the sick leaves thus increase the productivity. IAQ is also important to comply with the occupational health standards and regulations.
There are different kinds of IAQ Assessments available depending on what aspect of the air quality needs to be assessed or improved.
- Air sampling: Measuring concentrations of different IAQ parameters using direct reading monitors or integrated sampling instruments (e.g., VOCs, CO₂, PM2.5, CO).
- Ventilation assessment: Checking airflow rates and air distribution and calculating the amount of fresh air in the environment. Also, inspecting the HVAC unit for proper filters, intake air diffuser position, mold, and other contamination.
- Building inspections: Identifying sources of moisture, mold, or chemical emissions and ventilation system.
- Occupant surveys: Gathering information on thermal comfort and adverse health effects from building occupants.
Resources
Web Pages
Extensive IAQ Information
Learn MoreEPA Animation Series
Learn MoreHealth Canada Guidance
Learn MoreWebinars
"Where there's smoke..." Understanding Particulate Hazards Indoors and Out
2024. A key topic (and risk) in occupational and environmental health. Wildfire smoke has spread widely across North America this spring and summer, raising awareness and elevating concern. Speakers: Dr. Dave Stieb and John Oudyk, OHCOW Occupational Hygienist.
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RSI Day 2023 week 2: Implications of Indoor Environment Quality in an Office Setting
Speaker: Andre Gauvin. This presentation will describe areas of general comfort in an office building. Topics including lighting, noise, and indoor air quality are often overlooked and all compliment an ergonomic workstation set up to ensure workers are comfortable.
View WebinarCOVID Related Webinars
COVID made the issue of indoor air quality more immediate and crucial in countries all over the world. One of the positive things to emerge from the crisis was that more attention has since been given to the problem of human health and air quality, and the presence of germs and other contaminants in the air we breathe. Following are some webinars dealing with indoor ventilation in public and private working spaces
Occ-COVID Conversations: Let’s hear from the Engineers & stop the spread!
December 9, 2022 Speakers: Joey Fox, P. Eng, MASc, HVAC Engineer; Marianne Levitsky, MES, CIH, ROH, FAIHA, Occupational Hygienist; Stéphane Bilodeau, P.Eng., Ph.D., Fellow of Engineers Canada, Bioengineering Lecturer at McGill U., CTO at Smart Phases
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Clean Air Really Matters!
Friday, September 16, 2022 – An in-depth presentation on key COVID prevention strategies by a subject matter expert, along with professional framing and discussion with an OHCOW host – and an audience Q&A. Kevin Hedges, Occupational Hygienist, PH.D., CIH,COH; Joey Fox, P.Eng., MASc.
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Occ-covid Clean Air Playlist
From 2022: See a list of webinars on classroom ventilation, older buildings, risk assessment and more! A concise compilation of COVID era concerns about indoor air assessment that is still valid today.
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SARS-CoV-2, CO2, and You
2025 Speaker: Al Haddrell. A discussion of the various dynamics between CO2 and the airborne transmission of SARS-CoV-2. By understanding how these dynamics, you can limit your rexposure to an airborne virus.
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Collaborating on Solutions for Cleaner School Air
2024 Occ-Covid Series: What happens in schools affects millions of children and their families, and can drive illness and infection rates in society at large.
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