Is indoor air quality (IAQ) a health and safety concern?

ANSWER
Indoor air quality has become an important occupational health and safety issue. In the past few decades, energy conservation measures have led to airtight building construction that can create problems with IAQ. Frequently the ventilation systems are set to minimize the amount of fresh air entering and circulating within the building. This restriction impacts indoor air by allowing a build-up of air contaminants within the building that are not properly removed.
People spend a lot of time indoors -- for example, many office workers will spend their entire working day inside buildings. People working indoors often experience symptoms such as headaches, shortness of breath, coughing or nausea just to mention a few. However, it is rarely possible to prove that these symptoms are related to a particular indoor air contaminant. In fact, building occupants are simultaneously exposed to a wide range of indoor air contaminants.
 

QUESTION?

What are the common causes of IAQ problems?

ANSWER
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, lighting, excessive noise
Indoor air contaminants - chemicals, dusts, moulds or fungi, bacteria, gases, vapours, odours
Insufficient outdoor air intake
 

QUESTION?

What are indoor air contaminants?

ANSWER
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.

QUESTION?

What symptoms are often linked to poor indoor air quality?

ANSWER
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, and/or
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.

QUESTION?

What are some related health issues?

ANSWER
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.

QUESTION?

Is air contamination the only cause of these symptoms?

ANSWER
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, and ergonomics. It is important that all possible causes be investigated when assessing complaints.
Other OSH Answers documents on these topics include:
Noise - General
Thermal Comfort for Office Work
Office Ergonomics - Eye Discomfort in the Office
Ergonomics
Lighting Ergonomics - General

QUESTION?

Why do only some people seem to develop symptoms?

ANSWER
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. Some people may be exposed to more contaminants in the building than others and they may experience symptoms earlier than other people. As air quality deteriorates and/or the length of exposure increases, more people tend to be affected and the symptoms tend to be more serious.

 

QUESTION?

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

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

QUESTION?

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

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

QUESTION?

When should I start suspecting that IAQ may be a problem?

ANSWER
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.

QUESTION?

Are there laws or guidelines for IAQ?

ANSWER
Many Canadian jurisdictions do not have specific legislation that deals with indoor air quality issues. 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.
Several organizations* have published recommended guidelines for indoor air quality. For example:
Health Canada has prepared a number of publications such as:
Indoor air quality in office buildings: A technical guide
Exposure Guidelines for Residential Indoor Air Quality
Indoor Air Quality - Tools for Schools Action Kit for Canadian Schools
Dampness, Mold and Indoor Air
In the United States, the Occupational Safety and Health Administration (OSHA) has compiled information on Indoor Air Quality Standards.
In addition, IAQ is implied in most building codes as design and operation criteria. Building codes in Canada and the U.S. generally refer to the American Society of Heating, Refrigerating, and Air Conditioning Engineers* (ASHRAE) Standard 62.1-2004 "Ventilation for Acceptable Indoor Air Quality" (1989 or 1999 version may be cited), CSA International* Standard Z204-94 "Guideline for Managing Indoor Air Quality in Office Buildings", or other acceptable standards.
It is important to understand that most IAQ standards and guidelines are established to ensure the comfort of workers. So these values tend to be lower than regulatory values that are set to protect workers from possible health based hazards.
*We have mentioned these organizations as a means of providing a potentially useful referral. You should contact the organizations directly for more information about their information and/or services. (ASHRAE - http://www.ashrae.org/; CSA - http://www.csa.org/)

QUESTION?

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

ANSWER
It is not recommended that "regular" occupational exposure limits (e.g., OELs, TLVs®, PELs) be used to determine if the general indoor air quality meets a certain standard. Occupational exposure limits listed in health and safety regulations and the Threshold Limit Values® (TLVs) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) are intended as a guide to prevent illness or certain effects (like eye and nose irritation) in industrial situations. These limits may not be appropriate in office settings or for the home.
Occupational exposure limits 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 IAQ problems. Currently, there is not enough information available to predict the effects of exposure to several potentially harmful agents at the same time.

QUESTION?