Purifying Indoor Air: Keeping Outdoor Pollution Out

Outdoor air pollution is a serious issue that affects the health and well-being of people worldwide. While staying indoors can help reduce exposure to harmful pollutants, outdoor pollution can still seep into your home, affecting indoor air quality. Older homes, especially, may be more susceptible to leaks due to age-related damage and less airtight designs. To keep outdoor air pollution from getting indoors, it is essential to understand the sources of pollution and implement effective strategies to mitigate them. This includes source control, proper ventilation, and the use of air purification systems, which can help reduce the concentration of pollutants and improve the air you breathe inside your home.

Seal gaps in older homes to prevent outdoor pollutants from seeping in

Older homes are more susceptible to outdoor pollutants due to their lack of airtightness compared to newer, more energy-efficient homes. Over time, seals and weather-stripping around doors, windows, and other openings tend to break down, allowing polluted outdoor air to seep in. Therefore, it is crucial to seal any gaps and leaks in your home to prevent this.

Firstly, identify the areas where air may be leaking in, such as windows, baseboards, doors, and other openings. Inspect your home thoroughly for any visible gaps or cracks. Pay close attention to areas where different materials meet, such as between the walls and windows or doors. Don't forget to check your dryer vent to ensure it is not blocked, as this can be a fire hazard.

Once you have identified the areas of concern, you can use various materials to seal the gaps. For larger gaps, foam sealant can be an effective solution. Apply the foam from the inside of your home to fill in the gaps and create a tight seal. You can also use caulk, a duct seal product, or silicone to seal smaller cracks and openings. These materials are flexible and can be painted over to match the surrounding area.

Additionally, consider replacing exterior door bottoms and thresholds with ones that have pliable sealing gaskets. This will create a tighter seal and prevent polluted outdoor air from entering your home. If you have a fireplace, ensure the flue damper is kept tightly closed when not in use, and seal any air leaks around the fireplace chimney with fire-resistant materials such as sheet metal or furnace cement caulk.

By taking these measures to seal gaps and leaks in your older home, you can effectively prevent outdoor pollutants from seeping in, improving the indoor air quality and creating a healthier living environment.

Use a high-performance air purifier to filter particles and gases

Using a high-performance air purifier is an effective way to filter out particles and gases from indoor air. Air purifiers work by passing air through a filter, trapping polluting particles or gases, and then returning the cleaned air into the room.

There are several types of air purifiers available, each with its own advantages and disadvantages. HEPA filters, for example, are highly effective at cleaning particles out of the air. The diameter specification of 0.3 microns responds to the most penetrating particle size, and particles that are larger or smaller are trapped with even higher efficiency. Mechanical filters, which use fans to force air through a dense web of fine fibres that trap particles, are another option. While these filters can remove microscopic particles, they are ineffective against gases or odours.

Activated carbon filters, on the other hand, are designed to capture certain types of gases, including some odour-causing molecules. However, they are not as effective against certain gases like formaldehyde, ammonia, or nitrogen oxide. Ozone generators are another type of air purifier, but these are not recommended as they can produce dangerous indoor air quality by altering the chemical composition of the air.

When choosing an air purifier, it is important to consider factors such as room size and the type of pollutants you want to remove. The Clear Air Delivery Rate (CADR) is a value that reflects the volume of clean air an air purifier produces on its highest setting. A higher CADR means a faster and more efficient air purifier. The Association of Home Appliance Manufacturers (AHAM) recommends that the CADR of your air purifier is equal to at least two-thirds of the room's area.

In addition to CADR, noise level and speed settings are also important considerations. Many air purifiers have multiple speed settings, allowing you to adjust the purification level as needed. It is also worth noting that air purifiers with higher speed settings tend to produce more noise. Therefore, it is recommended to look for a purifier that can run below 50 decibels, which is the upper limit for normal conversation, watching TV, or sleeping.

Lastly, maintenance and operating costs are crucial factors when choosing an air purifier. All filters need to be regularly replaced as per the manufacturer's recommendations. Activated carbon filters, for instance, require replacement every three months, while mechanical filters can last up to 12 months. Energy consumption is another cost factor, as air purifiers need to run continuously to be effective.

Monitor indoor air quality with a live air quality monitor

Monitoring indoor air quality with a live air quality monitor is an effective way to keep outdoor air pollution from entering your home. Air quality monitors can help you become aware of your indoor air quality index, allowing you to take the necessary steps to improve the air you breathe.

Live air quality data can inform you when your indoor air is becoming too polluted, indicating when you need to mitigate the sources and effects of air pollution. These monitors use laser and infrared sensors to measure real-time pollution levels, especially PM2.5 and CO2, which can rise to dangerous levels indoors.

There are several options available for indoor air quality monitors, ranging from inexpensive to more advanced models. The Temtop M10 Air Quality Monitor, for instance, is a simple and inexpensive option, but it has been reported to have inaccurate or short-lived sensors. The PurpleAir Zen is another monitor that costs around $300 and can be used both indoors and outdoors. It uses the EPA AQI color scale to indicate air quality, with green representing good air and hazardous air indicated by deep violet or maroon.

If you're looking for a more comprehensive monitor, the SAF Aranet 4 is one of the most accurate CO2 monitors available and can act as a reliable indicator of your indoor air quality. For a more accessible option, the IKEA Vindriktning is available for as little as $15, although it may not be as accurate as the more expensive models.

In addition to these dedicated monitors, there are also free apps available, such as the Environmental Protection Agency's AirNow app, which provides air quality readings and forecasts for almost every corner of the US.

Limit indoor pollution sources such as mould, dust mites, and tobacco smoke

Mould, dust mites, and tobacco smoke are common sources of indoor pollution. Here are some ways to limit their presence in your home:

Mould

Mould is a type of fungus that grows in warm, damp environments with poor airflow. To prevent mould, focus on controlling moisture and improving ventilation:

• Keep your home well-ventilated by regularly opening windows, especially after activities that generate moisture, such as showering or cooking.
• Use extractor fans in bathrooms and kitchens to reduce moisture and prevent condensation, a major cause of mould.
• Avoid drying clothes indoors on radiators, as this increases moisture and condensation. Instead, dry clothes outside or in a well-ventilated room.
• Ensure furniture is not placed too close to walls, allowing air to circulate freely.
• Avoid overfilling wardrobes and cupboards, as this can prevent air circulation and create a damp environment conducive to mould growth.

Dust Mites

Dust mites are microscopic pests that can trigger allergies and asthma. They thrive in bedding, carpets, and soft furnishings, and their allergens can settle into dust and fabrics. To reduce dust mites:

• Regularly dust and vacuum to remove dust and mite allergens from surfaces and fabrics. Use a damp cloth or a vacuum with a HEPA (High-Efficiency Particulate Air) filter to trap and lock in dust mites.
• Consider replacing carpets with hard-surfaced flooring, as carpets can harbour dust mites and their allergens.
• Wash bedding and fabrics regularly to remove dust mite allergens.

Tobacco Smoke

Tobacco smoke, including secondhand smoke, is a significant source of indoor air pollution and can have harmful health effects on family members, especially children. To limit tobacco smoke pollution:

• Implement a strict no-smoking policy in your home and car.
• Encourage smokers in your household to quit smoking for their health and the well-being of those around them.
• Advocate for tobacco-free policies in public spaces, such as schools, workplaces, and restaurants, to protect yourself and your loved ones from secondhand smoke exposure.

By following these measures, you can effectively limit indoor pollution sources and improve the air quality in your home.

Increase ventilation by opening windows and using fans to disperse indoor pollutants

Improving indoor air quality is essential for maintaining a healthy living environment. One effective strategy to achieve this is to increase ventilation by opening windows and utilizing fans to disperse indoor pollutants. Here are some detailed guidelines to help you implement this strategy effectively:

Opening Windows

Opening windows is a simple yet effective way to increase ventilation and improve indoor air quality. By allowing outdoor air to enter your home, you can dilute and reduce the concentration of indoor pollutants. This is especially beneficial in areas where there may be limited options for mechanical ventilation, such as older homes or apartments without built-in air conditioning systems. However, it is important to be mindful of outdoor air pollution levels. If the outdoor pollution rises to unhealthy levels, it is advisable to keep windows closed until the air quality improves.

Utilizing Fans

Fans play a crucial role in enhancing ventilation and dispersing indoor pollutants. There are several types of fans that can be used for this purpose:

• Window or Attic Fans: Operating window or attic fans is an excellent way to increase the outdoor ventilation rate. These fans help draw in fresh air while exhausting stale air.
• Exhaust Fans: Bathroom and kitchen exhaust fans are particularly important for removing contaminants directly from the rooms where they are located. When showering or cooking, use these fans to exhaust pollutants, including water vapor and VOCs, before they spread to other areas of your home.
• Vent Hoods: In the kitchen, a vent hood above the stove can help capture and remove pollutants generated during cooking, such as gases and odors.

Combining Windows and Fans

For maximum effectiveness, combine the use of windows and fans. Open windows while operating fans to create a cross-breeze effect, facilitating the dispersal of indoor pollutants and the intake of fresh outdoor air. This strategy is especially beneficial during short-term activities that can generate high levels of pollutants, such as cooking, painting, or maintenance work.

Other Considerations

While increasing ventilation is a crucial step, it should be complemented by other measures:

• Source Control: Whenever possible, eliminate or reduce the sources of indoor pollution. For example, control humidity levels to prevent mold growth, minimize carpeting to reduce the trapping of pollutants, and store chemicals safely away from living areas.
• Air Purifiers: Consider using high-performance air purifiers, especially if outdoor pollution levels are high or if you have specific concerns, such as a family member with asthma.
• Filter Maintenance: Regularly clean or replace air filters to ensure optimal performance and avoid overloading your fans with dirty and clogged filters.

Frequently asked questions