Controlling Indoor Air Pollution: Tips For A Healthy Home

Indoor air pollution is a serious issue, causing approximately 3.2 million deaths globally each year, according to the World Health Organization. It is caused by the release of harmful pollutants such as fine particulate matter, carbon monoxide, and toxins, which can have detrimental effects on human health. The good news is that there are ways to control indoor air pollution and reduce the risk it poses.

One key strategy is source control, which involves eliminating or reducing the sources of indoor air pollution. This can be achieved by avoiding burning indoors, not using unvented fuel-burning appliances, opting for fragrance-free products, and not smoking or vaping indoors. Ensuring proper ventilation is another effective way to tackle indoor air pollution. Ventilation helps remove polluted indoor air and replace it with fresh, clean air from outside. Additionally, using air cleaners and filters can help remove airborne particles, especially when paired with adequate ventilation.

Other measures to control indoor air pollution include using safe building materials and furnishings, reducing the use of chemical products, and providing adequate filtration for combustion appliances. By implementing these strategies, it is possible to significantly improve indoor air quality and protect the health and well-being of those who spend a significant amount of time indoors.

Ventilation with outdoor air

Understanding the Importance of Ventilation

Begin by understanding the importance of ventilation in maintaining healthy indoor air. Indoor air can accumulate harmful pollutants, such as moisture, odors, gases, dust, and other pollutants that can adversely affect health. Ventilation helps to dilute and remove these indoor pollutants, creating a healthier living or working environment.

Increasing Outdoor Air Intake

One of the most effective ways to improve indoor air quality is to increase the amount of outdoor air coming indoors. This can be achieved by opening windows and doors to facilitate natural ventilation. Mechanical ventilation, such as fans and air conditioning systems, can also be utilized to increase the exchange of indoor and outdoor air.

Considering the Air Exchange Rate

It is essential to ensure adequate ventilation by considering the air exchange rate. The recommended air exchange rate for residential buildings is at least 0.35 air changes of outdoor air per hour to maintain good indoor air quality. Consult an HVAC technician or use online calculators to determine the air exchange rate in your space.

Timing Your Ventilation

Pay attention to the timing of your ventilation efforts. Opening doors and windows for 15 minutes each day is an effective way to increase ventilation. However, avoid doing so on days with poor outdoor air quality, or if you live close to busy highways, ports, airports, or factories with high emissions.

Using Exhaust Fans

Exhaust fans in bathrooms and kitchens are excellent for removing moisture, gases, and airborne particles. Be sure to run these fans during and after activities that generate pollutants, such as bathing or cooking. Ceiling fans can also improve airflow, especially when used in conjunction with open windows.

Addressing Specific Activities

Certain activities, such as painting, using hobby supplies, or engaging in chemical-intensive tasks, can generate high levels of pollutants. During these activities, it is crucial to provide extra ventilation. If possible, consider performing these activities outdoors to minimize the impact on indoor air quality.

Maintaining a Clean Environment

Keeping your indoor space clean and dry is essential for reducing indoor air pollution. Pay particular attention to areas like kitchens and bathrooms, where moisture and contaminants can accumulate. Promptly address any leaks or water damage to prevent the growth of mold and mildew.

Using Air Cleaners and Filters

In addition to ventilation, consider using air cleaners and filters to further improve indoor air quality. High-Efficiency Particulate Air (HEPA) filters, for example, are effective at removing pollutants like mold spores, pet dander, and tobacco smoke. Air cleaners can be integrated into vacuums, air purifiers, and heating or air conditioning systems for comprehensive air purification.

Monitoring and Controlling IAQ

To ensure the effectiveness of your ventilation strategies, consider investing in indoor air quality (IAQ) monitoring systems. These systems can provide real-time data on the levels of various pollutants, allowing you to make informed decisions about ventilation and air purification.

Combining Ventilation with Other Strategies

While ventilation is crucial, it is most effective when combined with other pollution control measures. Source control, for example, involves eliminating or reducing emissions from specific sources, such as gas stoves or building materials. By addressing the sources of pollution and implementing proper ventilation, you can create a healthier and more comfortable indoor environment.

Source control

Avoid Burning Indoors

• Fires, candles, and incense can release pollutants into the air. Opt for alternatives that do not produce smoke or use proper ventilation if burning is unavoidable.
• Do not use kerosene heaters, camp stoves, or other unvented fuel-burning appliances indoors. These can emit toxic gases.
• If using a kitchen range hood that vents outdoors, always turn it on while cooking, and set it to the highest fan speed.

Go Fragrance-Free

Air fresheners and strongly scented products often contain volatile organic compounds (VOCs) and other harmful chemicals. Minimize their use or opt for fragrance-free alternatives.

Don't Smoke or Vape Indoors

Tobacco smoke and aerosols from vape products release numerous harmful pollutants into the air. Restrict smoking and vaping to outdoor areas away from doors and windows. If possible, avoid smoking or vaping altogether.

Opt for Low-Emitting Building Materials and Furnishings

• When building or renovating, choose materials and furnishings that emit lower levels of VOCs. Examples include bamboo, wool carpets, and latex paint.
• Avoid materials that contain formaldehyde, and air out new carpet or furniture before bringing them indoors.

Keep Pets Off Furniture and Beds

Pets can be a source of indoor air pollution, especially for individuals with allergies. Keep pets off furniture and beds to reduce exposure to pet dander.

Use Dust Mite Covers and Vacuum Regularly

• Use dust mite mattress and pillow encasements for individuals allergic to dust mites.
• Vacuum with a HEPA vacuum at least weekly to reduce dust and other pollutants from carpets and rugs.

Improve Ventilation During Chemical Use

When using products containing chemicals or VOCs, improve ventilation by opening doors and windows. Use these products when people are not around and always follow the instructions on the label.

Air cleaners/filtration

Air cleaners and filtration systems are an effective way to improve indoor air quality. They can be used in conjunction with source control and ventilation to reduce indoor air pollution.

Types of Air Cleaners/Filtration Systems

• Portable air cleaners: These are designed for single-room use and are practical for existing homes where the addition of a central air cleaner is too costly or not possible. They are also useful when air cleaning is needed in a specific room or area of the house.
• Central air cleaners: These are larger units that can be used for large rooms or the whole house. They are often combined with technologies such as ESPs (electrostatic precipitators), HEPA (high-efficiency particulate air) filters, PCO (photocatalytic oxidation), and UVGI (ultraviolet germicidal irradiation) to remove particles and chemical vapours from the air.
• In-duct air cleaners: These are installed in the ductwork of a building's heating, ventilation, and air conditioning (HVAC) system. They can be effective in improving the air quality of the entire home, as most HVAC systems circulate large volumes of filtered air.
• Air scrubbers: These use UV light and ions to remove pollutants from the air.
• Air purifiers: These eliminate pollutants such as dust, pollen, mould spores, and pet dander. They can also remove VOCs, carbon monoxide, and other harmful chemicals.

Factors to Consider When Choosing an Air Cleaner/Filtration System

• Installation: In-duct air cleaners require an access point for inspection, maintenance, and repair.
• Purchasing costs: Consider not only the initial price but also the ongoing costs of operating the system and cleaning/replacing filters.
• Odour removal: Air cleaners designed for odour removal may not be effective against all types of gases and can add unwanted odours.
• Soiling of walls and surfaces: Ion generators can cause soiling when the electric charge is no longer strong enough to suspend particles in the air, causing them to be deposited on walls and other surfaces.
• Noise: Portable air cleaners with fans may emit noticeable noise, while fanless units are generally less effective.

Examples of Air Cleaner/Filtration Technologies

• HEPA filters: These are highly efficient at capturing dust, pollen, and mould spores, removing particles as small as 0.3 microns.
• MERV rating: This scale rates the effectiveness of air filters based on their ability to remove solid particles, with ratings ranging from 1 to 20. A higher MERV rating indicates greater removal efficiency for smaller particles.
• Activated carbon: This highly porous material is effective at removing gases and odours from the air and is often used in combination with primary filters to capture smaller particles.
• Ultraviolet (UV) light: UV light is effective at destroying bacteria, viruses, and other organic matter, especially mould spores. It is often combined with HEPA filters for optimal air cleaning.

Maintenance of Air Cleaners/Filtration Systems

To maintain the efficiency of air filters and cleaners:

• Ensure the filter fits tightly to prevent air bypass.
• Check for dust and debris buildup at least monthly during heavy use.
• Replace or clean the filter as recommended by the manufacturer to maintain efficiency and reduce strain on the system.
• Consider installing a pressure gauge to accurately indicate when a filter needs changing.
• Some filters or air cleaners have sensors that indicate when replacement is necessary.
• For HEPA filters, install a low-efficiency pre-filter upstream to prolong the useful life of the filter.

Building materials and furnishings

To control indoor air pollution from building materials and furnishings, it is important to select products that emit little to no harmful chemicals. Here are some specific ways to achieve this:

• Opt for low-emission products: Look for building materials and furnishings that are low-emission, low-toxicity, and low-VOC. Avoid products that contain chemicals such as formaldehyde, benzene, and methylene chloride. Formaldehyde is commonly found in pressed-wood products, such as plywood, furniture, and other pressed-wood products, and can off-gas over time.
• Use water-based products: Water-based adhesives, sealants, and coatings are often lower in VOCs than their solvent-based counterparts. They are generally safer to handle and have lower health risks.
• Improve ventilation: During and after the installation of building materials and furnishings, ensure proper ventilation to reduce the concentration of pollutants in the indoor air. Open windows, use exhaust fans, and follow manufacturer recommendations for ventilation during and after installation.
• Airing out: Request that building materials and carpets be aired out for at least 72 hours before installing them. This helps to reduce the initial release of VOCs.
• Encapsulation: For materials that contain formaldehyde or other pollutants, consider encapsulation by applying barrier coatings or sealants. This creates a barrier between the material and the indoor air, reducing emissions.
• Materials minimization: Use the minimum amount of materials required, especially adhesives, to reduce potential emissions.
• Installation sequencing: Plan the installation order of materials to minimize the interaction of different chemicals. For example, install soft finishes, such as carpets, after painting to reduce the absorption of VOCs.
• Avoid disturbing old building materials: When remodelling or demolishing, be cautious when dealing with old building materials that may contain asbestos or lead paint. Cover and leave them undisturbed if possible. If disturbance is necessary, follow recommendations from the U.S. Environmental Protection Agency or seek professional help.

Combustion appliances

Under certain conditions, these appliances can produce combustion pollutants that can be harmful to your health. The types and amounts of pollutants produced depend on the type of appliance, how well it is installed, maintained, and vented, and the kind of fuel it uses. Some common pollutants produced from burning these fuels are carbon monoxide, nitrogen dioxide, particles, and sulfur dioxide.

• Ventilation: Ensure proper ventilation by opening windows or doors when using combustion appliances, especially if there is no range hood or exhaust fan. If possible, use a range hood that vents to the outdoors and turn it on while cooking. Leave it on for 10-20 minutes after finishing cooking.
• Use of Vented Appliances: Opt for vented appliances whenever possible. These appliances are designed to carry the combustion pollutants outside the home through a duct, chimney, or pipe. Examples of vented appliances include most furnaces, wood stoves, fireplaces, gas water heaters, and gas clothes dryers. However, ensure that the vent system is properly designed, installed, and maintained to prevent indoor pollutant buildup.
• Avoid Unvented or Poorly Vented Appliances: Unvented or poorly vented combustion sources, such as most gas stoves, kerosene heaters, and charcoal grills, release combustion pollutants directly into the home. Using charcoal grills or gas stoves for home heating can produce extremely high levels of indoor air pollutants.
• Regular Inspection and Maintenance: Have your combustion appliances, such as wood heaters and gas stoves, inspected and maintained regularly by a trained professional. This is crucial because appliances that are not working properly can produce dangerous pollutants like carbon monoxide.
• Carbon Monoxide Monitors: Install carbon monoxide monitors in your home, especially if you rely on combustion appliances for heating, hot water, or cooking. Carbon monoxide is a dangerous gas that can interfere with the blood's ability to carry oxygen.
• Air Cleaning Devices: For homes that rely on wood-burning for heat or cooking, consider using an air cleaning device with HEPA filtration to provide some protection from the soot and smoke produced by these appliances.
• Fuel Choice: Always use the correct fuel for the appliance. For kerosene heaters, use only water-clear ASTM 1-K kerosene. Never use gasoline in a kerosene heater as it can cause a fire or an explosion.
• Fuel Efficiency: Choose appliances that are the correct size for the area you want to heat. Using an oversized appliance may produce more pollutants and is not an efficient use of energy.
• Proper Installation: Ensure that combustion appliances are professionally installed following the manufacturer's instructions and applicable building codes. Improperly installed appliances can release dangerous pollutants and create a fire hazard.
• Avoid Using Cooking Appliances for Heating: Never use a cooking stove, oven, or dryer to heat your home. Misusing gas appliances in this way can produce fatal amounts of carbon monoxide and high levels of nitrogen dioxide.
• Avoid Idling Cars in Garages: When idling cars or using kerosene heaters in an attached garage, the pollutants produced can enter the main house, contributing to indoor air pollution.
• Use Electric Alternatives: Consider using electric alternatives, such as high-efficiency electric appliances or solar heating systems, instead of combustion appliances to reduce indoor air pollution.

Frequently asked questions