Indoor Air Quality: Common Pollutants Revealed

Indoor air pollution is a serious environmental hazard that can have detrimental effects on human health. Common indoor air pollutants include excessive moisture, volatile organic compounds (VOCs), combustion products, radon, pesticides, dust particles, viruses, and bacteria. These pollutants can enter the home through various sources, such as cooking stoves, building materials, and outdoor air pollutants. Poor indoor air quality can cause or contribute to respiratory infections, lung cancer, asthma, and other chronic lung diseases. As such, it is important to identify the sources of indoor air pollutants and implement strategies to improve indoor air quality, such as ventilation and the use of air filters.

Volatile organic compounds (VOCs)

• Paints, varnishes, and waxes
• Cleaning, disinfecting, cosmetic, degreasing, and hobby products
• Fuels
• Building materials and furnishings, such as furniture and carpets
• Tobacco smoke

Concentrations of VOCs are typically much higher indoors compared to outdoors, with studies finding levels to be 2 to 5 times higher, and up to 10 times higher in some cases. This is due to the widespread use of products containing organic chemicals in indoor environments. The use of these products can expose individuals to very high pollutant levels, and elevated concentrations can remain in the air long after the activity is completed.

The health effects of VOC exposure vary, with some compounds being highly toxic and others having no known health effects. Some immediate symptoms that may occur soon after exposure include eye, nose, and throat irritation, headaches, nausea, dizziness, and difficulty breathing. Long-term exposure to certain VOCs can lead to more severe health issues, including potential damage to the liver, kidneys, and central nervous system, and some compounds are suspected or known to cause cancer in humans.

To reduce exposure to VOCs, it is recommended to increase ventilation when using products that emit them, read product labels, avoid or limit the use of items with harmful ingredients, safely dispose of unwanted products, and choose products with lower VOC content.

Combustion products

Indoor combustion pollutants can also be caused by environmental tobacco smoke, unvented kerosene and gas space heaters, wood stoves, fireplaces, and gas stoves. These sources release major pollutants such as carbon monoxide, nitrogen dioxide, and particles. Carbon monoxide is particularly dangerous as it is a colorless and odorless gas that can cause serious health issues and even death if inhaled in high concentrations. It interferes with the delivery of oxygen throughout the body, and the symptoms of carbon monoxide poisoning can be similar to those of the flu or food poisoning.

Another source of indoor combustion pollutants is the use of gas-fired appliances, including furnaces, water heaters, ranges, and dryers. These appliances produce carbon dioxide, carbon monoxide, nitrous oxides, and water vapor. Improper ventilation or negative air pressure around these appliances can cause backdrafting, allowing combustion pollutants to enter the home. It is important to ensure that gas-fired appliances are properly vented and maintained to prevent exposure to these harmful pollutants.

In addition, activities such as burning incense, grilling foods, using the oven's cleaning cycle, and hobbies that produce smoke or flame can increase indoor combustion pollution levels. Outdoor sources of combustion pollutants, such as nearby wood stoves, fireplaces, motor vehicle traffic, and gasoline-powered equipment, can also contaminate indoor air. The only sure way to eliminate indoor combustion pollutants is to remove the sources of these pollutants from the home and garage.

To reduce exposure to indoor combustion pollutants, it is recommended to use "sealed combustion" or "direct vent" gas appliances, which have completely sealed exhaust vents and air supplies. Regular maintenance and following manufacturer instructions are crucial for all combustion appliances to minimize the release of harmful pollutants.

Excessive moisture

Moisture problems often arise when warm moist air encounters a cool surface, such as a mirror, window, or the wall of a cooler space. Cooler air holds less moisture, so the excess condenses into droplets on the surface. These surfaces then become breeding grounds for mold, mildew, and dust mites, which can cause allergies, asthma, and other respiratory issues. High humidity also facilitates the "off-gassing" of toxins in furniture or cleaning products.

The amount of moisture in indoor air affects the health and comfort of that space. High humidity levels can cause irritating odors, particles, and vapors, as well as increasing the concentration of certain pollutants. For example, water vapor can combine with sulfur dioxide to form sulfuric aerosols, acids, and salts, which can irritate the skin and respiratory system.

Biological pollutants such as bacteria, viruses, and fungi also thrive in environments with high humidity. Viruses like polio and herpes are more likely to spread in environments with more than 50% relative humidity. Additionally, pests like cockroaches and dust mites are more likely to invade a home with high moisture levels.

To reduce excessive moisture and improve indoor air quality, several measures can be taken:

• Using a dehumidifier to remove moisture from the air
• Turning on air conditioning or fans to circulate and replace humid air with cooler, less muggy air
• Avoiding activities that increase humidity, such as using the oven or taking hot showers

Radon

If elevated levels of radon are detected, a mitigation system can be installed to collect radon gas from underneath the building and vent it outdoors, thereby reducing indoor radon levels. Knowing your level of radon risk and fixing it if necessary may save lives. Radon levels can temporarily increase due to severe storms or periods of high winds, so testing should not be conducted during or immediately after such events.

Pesticides

To minimize exposure to pesticides, it is recommended to use non-chemical pest control methods where possible. This includes removing moisture by fixing leaks and drying out wet materials, blocking pest entryways, and increasing ventilation. If pesticides must be used, it is important to follow the manufacturer's directions for use and disposal, only using the recommended amounts, and storing them in their original containers, out of the reach of children.

To avoid having to use pesticides, keep your home clean, dry, and well-ventilated. This will help prevent pest and odour problems. If you use a pest control company, choose one carefully and ask for an inspection and written control program before signing a contract.

Frequently asked questions