Indoor Air Quality - General

What is meant by indoor air quality (IAQ) for workplaces?

Indoor air quality (IAQ) issues result from interactions between building materials and furnishing, activities within the building, climate, and building occupants. The Canadian Committee on Indoor Air Quality and Buildings states that a healthy indoor environment is one that contributes to productivity, comfort, and a sense of health and well-being. Good IAQ will include air that: To maintain acceptable air quality, a workplace must maintain sanitation and recognize and correct water related issues quickly. Maintaining good air quality requires effort by both the building staff and occupants. NOTE: This OSH Answers document focuses on non-industrial workplaces.

• context is free from unacceptable levels of contaminants, such as chemicals and related products, gases, vapours, dusts, moulds, fungi, bacteria, odours, etc.
• context provides a comfortable indoor environment including temperature, humidity, air circulation, sufficient outdoor air intake, etc.

What are indoor air contaminants?

Examples of common indoor air contaminants and their main sources include:

• context Carbon dioxide (CO2) – from building occupants and combustion of fuels such as gas and oil furnaces and heaters.
• context Carbon monoxide (CO) – from vehicle exhaust brought into the buildingbuiding by air intakes.
• context Dust, fibreglass, asbestos, gases, including formaldehyde – from building materials.
• context Vapours, volatile organic compounds (VOCs) – from copying and printing machines, computers, carpets, furnishings, cleansers and disinfectants, solvents, pesticides, disinfectants, glues, caulking, paints etc.
• context Dust mites – from carpets, fabric, foam chair cushions.
• context Microbial contaminants, fungi, moulds, bacteria – from damp areas, wet or damp materials, stagnant water, condensate drain pans, etc.
• context Ozone – from photocopiers, electric motors, electrostatic air cleaners.
• context Other sources: tobacco smoke, perfume, body odour, food, etc.

What symptoms are often linked to poor indoor air quality?

IAQ issues do not affect everyone in the same way. When it is an issue, it is common for people to report one or more of the following symptoms: 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 issues more difficult.

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

Why do only some people seem to develop symptoms?

• context As with any other occupational illness, not all people are affected with the same symptoms or to the same extent. Some people may be more sensitive than others or have pre-existing health conditions. Some people may be exposed to more contaminants in the building than others and they may experience symptoms earlier than other people, or experience more severe symptoms.
• context As air quality deteriorates or the length of exposure increases, more people tend to be affected and the symptoms tend to be more serious.

What are some related health issues?

• context Occupants of buildings with poor IAQ report a wide range of health issues. Health issues and illnesses may develop soon after exposure, whereas exposure to other contaminants may produce health effects in future. Legionnaires’ Disease is an example of an illness caused by bacteria which can contaminate a building's air conditioning system.
• context A certain percentage of workers may react to chemicals in indoor air, each of which may occur at very low concentrations. Such reactions are often known as environmental sensitivities or multiple chemical sensitivities (MCS).
• context Some specific diseases have also been linked to or made worse by specific air contaminants or indoor environments, such as asthma being associated with damp indoor environments. In addition, some exposures such as asbestos and radon may not cause immediate symptoms but can lead to cancer after many years of exposure.

Is air contamination the only cause of these symptoms?

No. Feelings of discomfort and illness may be related to any number of issues in the total indoor environment. Other common causes may include noise levels, thermal comfort (temperature, humidity, and air movement), lighting, ergonomics, and psychological aspects of work (e.g., stress, workload, etc.). It is important that all possible causes be investigated when assessing complaints. Other OSH Answers documents on these topics include:

• context Noise – Basic Information
• context Thermal Comfort for Office Work
• context Office Ergonomics - Eye Discomfort in the Office
• context Ergonomics
• context Lighting Ergonomics - General
• context Mental Health - Introduction
• context Psychological Health and Safety – Assessing Psychosocial Hazards

Can a person become sensitive to IAQ contaminants as time passes?

• context It seems possible. Some people may not be sensitive to IAQ issues in the early years of exposure but can become sensitized as exposure continues over time.

Are there laws or guidelines for IAQ in non-industrial workplaces?

• context Many Canadian jurisdictions do not have specific legislation that deals with indoor air quality issues in non-industrial workplaces. In the absence of such legislation, the "general duty clause" applies. This clause, common to all Canadian occupational health and safety legislation, states that an employer must provide a safe and healthy workplace. Thus, making sure the air is of good quality is the employer's duty.
• context Several organizations* have published recommended guidelines for indoor air quality. For example, the Government of Canada has prepared a number of publications on air quality. Note that indoor air reference limits (IARLs) have been published by Health Canada, and other organizations. Other guidelines recommend that contaminants be kept at or below one tenth of their listed OEL.
• context In addition, IAQ is stated or implied in most building codes as design and operation criteria. Building codes and health and safety legislation in Canada generally refer to a version of the American Society of Heating, Refrigerating, and Air Conditioning Engineers* (ASHRAE) Standard 62.1 Ventilation for Acceptable Indoor Air Quality (or previous versions), or other acceptable standards.
• context Please see the OSH Answers Indoor Air Quality Legislation for more details.
• context *We have mentioned these organizations as a means of providing a potentially useful referral. You should contact these organizations directly for more information.

Why can't I use chemical occupational exposure limits for indoor air contaminants?

The concentration limits for contaminants that are specified in the health and safety legislation that are referred to as occupational exposure limits (OEL), threshold limit values (TLVs ®), or permissible exposure limits (PEL): These limits are not appropriate for: Therefore, it is not recommended that "regular" occupational exposure limits (OELs) such as TLVs®, and PELs be used to determine if the general indoor air quality meets a certain standard. OELs use dose-response data which show the health effects of repeated exposure to one specific chemical. Similar data is not available for long-term, low-level exposures to a combination of contaminants as is the case for many IAQ situations.

• context apply to industrial workplaces where the worker composition (e.g., age and pre-existing conditions) is not the same as that for non-industrial workplaces,
• context are based on a 40-hour work week for the lifetime of an industrial worker (e.g., worker at chemical manufacturing facility), and
• context are set to protect workers from possible health-based hazards (e.g., eye and nose irritation) and are NOT fine lines between safe and dangerous exposures.
• context control of air quality for non-industrial workplaces (e.g., offices or homes),
• context control of community air pollution, and
• context use by anyone who has not been trained in industrial hygiene.

What should I do if I suspect that I am ill from poor IAQ?

• context If you think that you may be ill from IAQ issues, it is important to keep track of when you get your symptoms (aches, pains, headaches, etc.) and when they go away. This record will help your safety officer or health professional determine what the issue is related to. You may also wish to discuss your symptoms with your health professional to rule out any other medical conditions.
• context As with any other occupational health and safety concern, you can discuss your concerns with the health and safety representative, the health and safety committee, your supervisor, safety co-ordinator, industrial hygienist, or any other member of your company that is responsible for health and safety.
• context Your local government jurisdiction may also be able to provide information and advice advicse on workplace health and safety.

When should I start suspecting that IAQ may be an issue?

• context When there is an issue 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.
• context 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.

Who should investigate?

• context Many people may play a role in helping to resolve an IAQ issue including the building owner, employer, property manager, and occupants. Who conducts your investigation will depend on your workplace, but in general, you should have one person who is the leader, and perhaps a small team, including a representative from the health and safety committee, or the union, if appropriate. The expertise of many other people such as health and safety or building maintenance personnel, and the experience of everyone in the workplace will all be important in finding the root cause of your IAQ issue.

How should possible IAQ issues be investigated?

Unfortunately finding the source or cause can often be difficult. The steps taken may vary from situation to situation but will include:

• context Conduct a walk-through inspection.
• context Examine the complaints to see if there is a pattern.
• context Inspect the ventilation system to make sure it is operating properly (e.g., the right mix of fresh air, proper distribution, filtration systems are working, etc.).
• context Look for possible causes (e.g., source of a chemical, renovations, mould, etc.).
• context Rule out other causes of the symptoms such as noise, thermal comfort, humidity, ergonomics, lighting, etc.
• context Conduct a survey to help pin-point work sources and causes (see below for a sample survey).
• context Consider help or air testing by a qualified professional.

What information can the pattern of complaints reveal?

Examining the pattern of complaints may help indicate what element should be examined further. Adapted from: Alberta Government (2009). Indoor air quality tool kit.

• context Widespread – no pattern — Possible Source or Cause: Check entire HVAC system for functioning, mould, etc.
• context Widespread – no pattern — Possible Source or Cause: Check air intakes for contamination or poor location
• context Widespread – no pattern — Possible Source or Cause: Look for sources that are throughout the building, such as cleaning products
• context Widespread – no pattern — Possible Source or Cause: Consider other factors such as lighting, noise, etc.
• context Localized – reports are from 1 room or a single HVAC zone — Possible Source or Cause: Check the HVAC in the effected areas
• context Localized – reports are from 1 room or a single HVAC zone — Possible Source or Cause: Check if there are multiple air intakes to the building and if one may have an issue
• context Localized – reports are from 1 room or a single HVAC zone — Possible Source or Cause: Look for storage of materials, cleaning products or equipment that is specific to that area
• context Localized – reports are from 1 room or a single HVAC zone — Possible Source or Cause: Ask if there have been any changes to that area recently, such as construction, new items, etc.
• context Individuals — Possible Source or Cause: Check for drafts, heat loss or gain, and other temperature or ventilation issues (such as a blocked vent)
• context Individuals — Possible Source or Cause: Ask if there have been any changes to that area recently
• context Symptoms begin at the start of the work shift — Possible Source or Cause: Review HVAC system’s operation. For example, a contaminant may accumulate when the building is not occupied or when the HVAC has been operating at reduced rates overnight
• context Symptoms get worse over a period of time (the day or shift) — Possible Source or Cause: Make sure the HVAC system has the capacity to support the number of people and activities occurring while the building is occupied.
• context Intermittent symptoms — Possible Source or Cause: Look for patterns in hourly, daily, weekly, or seasonal changes
• context Intermittent symptoms — Possible Source or Cause: Determine if symptoms occur during specific weather events
• context Intermittent symptoms — Possible Source or Cause: Investigate occasional activities such as waxing or cleaning the floors, vacuuming, painting, etc. occur at these times
• context Single event — Possible Source or Cause: Determine if there was a specific event, such as a spill or repair to equipment

What is a sample Assessment and Resolution flow chart for IAQ?

What is an example of a health survey to help identify if IAQ is related to reported issues?

The following is a sample of a questionnaire that could be used to help identify if an office or building has an indoor air quality problem. SAMPLE HEALTH SURVEY (Adapted from: Indoor Air Quality Health and Safety Guide, prepared by CCOHS)

• context Use this questionnaire in consultation with a health and safety professional or other expert(s).
• context Modify or customize this questionnaire to address the conditions and work practices at your workplace.
• context Analyze the responses in consultation with an expert.

When should I seek professional help?

• context If the issue persists even after you have identified and corrected some issues, you may want to seek professional assistance. You may also require help if the issue requires immediate attention and your resources are limited, or if your investigation does not reveal possible causes.

How do I select and IAQ consultant?

There are no legal requirements for a person to be designated as an indoor air quality consultant. It is the client's responsibility to find a competent consultant who is qualified by education, knowledge, and experience. When hiring consultants, assess their professional background including education, professional credentials, the reputation of their firm, and, most important, demonstrated success in resolving similar situations. Ask for references. See the OSH Answers Fact Sheet on Selecting and Hiring a Health and Safety Consultant for more information.