The sources of indoor air pollution vary. Some of them, such as building materials and furnishings, release pollutants more or less continuously. Others, such as cooking, smoking, cleaning or redecorating, release them intermittently.
Health and safety legislation in Canada generally refers to ASHRAE ventilation standards for acceptable indoor air quality.
Pollutants
Poor air quality can be due to many sources, including combustion pollutants (gasoline, kerosene and wood products), volatile organic compounds, tobacco smoke, bioaerosols and pesticides. In addition, radon and asbestos can be contributing factors. These chemicals may cause immediate health problems, such as irritation of the eyes, nose and throat, headaches, fatigue and other symptoms. Other health effects may show up only years after exposure or over a long period of time, such as some respiratory diseases and lung cancer.
Because of the large amount of time we spend indoors, it is important to know how to reduce indoor pollutants and their negative health effects. A good place to start is with a safety guide prepared by EPA and the Consumer Product Safety Commission, with steps for reducing indoor pollutants in your home. You can also find out more by visiting our page on common household pollutants.
Allergens
Allergens are substances that cause an allergic reaction in the body, which can include sneezing, itchy eyes, nose or throat, skin rash, asthma, nausea and diarrhea. Some people can also experience a life-threatening reaction called anaphylaxis. Allergens can come from plants, animals (like dander and fur), or food such as peanuts and shellfish.
Allergies in the indoor setting often result from the inhalation of airborne allergens such as dust, some pollen, mold and animal dander. Other sources of allergy symptoms in the home may include a lack of ventilation, using chemicals or toxic cleaners, keeping indoor plants that produce pollen and support mold growth, and a poorly maintained furnace and chimney.
Luckily, there are many ways to improve indoor air quality for those with allergies and asthma. Simple measures such as regular vacuuming, saving indoor plants for outside, and cleaning with nontoxic cleaners can help to reduce allergens in the home. Professionals are also able to help with hard-to-reach places like air ducts.
Humidity
Many health problems linked to indoor air quality, such as headaches, fatigue and difficulty concentrating, and irritation of the eyes, nose, throat or lungs can be traced back to certain air pollutants and humidity conditions. Other health effects, such as asthma and some cancers, are seen only after years of exposure.
Typical sources of indoor pollutants in office buildings are environmental tobacco smoke, asbestos from insulating and fire-retardant building materials, formaldehyde from pressed wood products, other organics from building materials, office equipment and furnishings, noxious chemical fumes, restroom air fresheners, and cleaning materials and activities.
If an activity is likely to produce large amounts of short-term pollutants, increasing ventilation before and during the activity can reduce their concentration in the air. This will also move pollutants away from occupants and reduce their potential for contact with occupant surfaces. This is an especially important measure when an occupant has known allergies to a pollutant or other sensitivities to chemicals.
Temperature
The temperature of the air affects how chemical pollutants function in the indoor environment. Lower temperatures can make it harder for odors and particles to evaporate, while higher temperature reduces their ability to do so. Some airborne chemicals, such as VOCs (volatile organic compounds), release more of their vapors at warmer temperatures. Controlling indoor humidity levels mitigates the release of these vapors.
Some chemical pollutants, such as carbon monoxide, can be deadly at high concentrations. This odourless and tasteless gas is produced by incomplete combustion of fossil fuels, such as in tobacco smoke or malfunctioning central heating furnaces.
Many of the same issues that cause poor indoor air quality in homes can be found in office buildings. These include secondhand tobacco smoke, volatile organic compounds, molds and allergens, radon, and inadequate ventilation. Source control, ventilation, and air cleaning devices are the main solutions. Encourage building management to follow the guidance provided in EPA’s Building Air Quality: A Guide for Building Owners and Managers.