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We started this post to investigate the air purifying qualities of our houseplants. We wanted to know which plants do the best job at removing indoor pollutants that reduce air quality. Several articles say that houseplants can remove pollutants like volatile organic compounds (VOCs) from the air, such as benzene, formaldehyde and trichloroethylene. And many of them reference NASA’s Clean Air Study, conducted in 1989, which looked at ways to clean the air in space stations. But more recent scientific study has shown that plants don’t clean indoor air quickly enough to significantly reduce VOCs. You would need to have 10-1000 plants per square metre of floor space in your home to improve your air quality as efficiently as just opening a window or using a building air handling system.. That’s probably not what your home looks like, unless you live in a greenhouse or a plant store.
So houseplants aren’t the answer to how we clean our indoor air. (Even though we still love the positive psychological and physiological benefits of our oxygen-producing house plants (all 30+ and counting)). Then what will do the job?
Topics in this post:
Why do we need to clean the air in our homes?
So, what’s wrong with our indoor air quality anyways? Why even bother “cleaning” or “purifying” the air? Well, poor indoor air quality can lead to Sick Building Syndrome (SBS) with symptoms such as eye, nose and throat irritation, headaches, fatigue and irritability, chest tightness and wheezing, nausea and loss of coordination, and skin dryness and irritation. So, it’s pretty important to be mindful about keeping your indoor air fresh and clean.
The quality of the air outdoors and emissions from indoor sources influence our indoor air quality. Outdoor sources can include pollens that trigger allergies in some people. As well as cars and other combustion sources that exhaust contaminants like carbon monoxide, nitrogen and sulphur oxides, dust-like particles, and ozone. Indoor sources of pollutants tend to be related to:
- Heating and cooking processes;
- Construction materials and home furnishings; and
- Day-to-day indoor activities.
Several indoor sources release volatile organic compounds (VOCs) into the air. VOCs are chemical gases emitted from certain solids or liquids that can cause short- and long-term negative health effects.
Heating & cooking
Oil and gas furnaces, and wood-burning stoves can release contaminants, including carbon monoxide, oxides of nitrogen and sulphur, aldehydes and polycyclic aromatic hydrocarbons. Gas-fired stoves can also raise indoor levels of carbon monoxide, nitrogen oxides and formaldehyde.
Properly vent and regularly maintain heat and cooking sources (including your gas-fired oven and pilot light) to minimize airborne pollutants.
The way you cook your food can also impact your indoor air quality. When you heat cooking oils, their chemical composition starts to change. And if they get too hot, they can pass their smoke point and begin to burn and smoke. At this point an oil breaks down, and releases toxic fumes and free radicals that are unhealthy to breathe and eat. We wrote a post about how to pick the healthiest cooking oils, and which oils are ideal for specific cooking methods and temperatures.
Construction materials & home furnishings
Construction materials can include fibreglass and asbestos, which are unsafe to breathe in. Home furnishings with fibres made up of synthetic polymers can degrade over time and release contaminants such as formaldehyde. Furnishings and construction materials can include drapery, rugs and fabrics, foam insulation, laminate wood flooring and particle board flooring underlay. Sometimes contaminants are “sealed” into your home after construction, but can be released during building renovations.
Day-to-day indoor activities
There are some obvious sources of pollutants from day-to-day indoor activities such as smoking, but a lot of less obvious ones too. These include cleaning products and disinfectants, moth repellents and air fresheners, furniture waxes and polishes, paints, paint strippers and other solvents, pesticides used for house plants, fabric protectors. Personal care products can emit contaminants too, including anything with an aerosol spray, dry-cleaning clothing, nail polish, shampoos, deodorants, and other scented products. Office equipment such as copier and printers can have an effect too by releasing particulate matter into the air.
When we exhale we also increase the levels of carbon dioxide (CO2) in our homes, which are often found to be higher indoors than outdoors. Elevated levels of carbon dioxide can lead to headache, fatigue and feelings of stuffiness.
So, how can you clean your indoor air?
There are many strategies you can use to improve and maintain your indoor air quality, from avoiding contaminants in the first place to improving your home’s ventilation. Ventilation, an exchange of indoor and outdoor air, is an important part of the picture. Homes without adequate ventilation can have higher levels of indoor air pollution, and increased humidity and moisture. High humidity and moisture can encourage mould growth and dust mites that can trigger allergens and asthma.
Here are five common strategies to keep your home’s air clean and fresh year-round. These strategies work on their own, but work even better in combination.
1. Just open a window
Kind of a no-brainer, but it’s important to remember how effective regularly opening windows or doors can be. Opening a window lets fresh air in and pushes stale air out. The indoor air in the average North American home or workplace can be replaced by air from the outside in about an hour. Open doors and windows a few times a day to “air out” your home. Even better if you can create a cross breeze by opening them on opposite ends of your space. This will naturally ventilate your home and help to get rid of pollutants, allergens and excess moisture.
2. Avoid contaminants in the first place
Reduce indoor sources of pollution by being mindful about what you bring inside, and how you maintain your home. Here are some additional ways to reduce sources of contaminants inside your home:
- Make your home smoke free, including from cigarettes, candles and incense, and wood fires. (I know, this recommendation sucks. There’s some controversy about which candles are better to use, but it’s probably a good idea to avoid ones made of paraffin (petroleum-based) wax or with artificial scents. I love the smell of a wood fire just like the next person. So, if you’re going to have one then well-ventilate your home or use an outdoor fire pit.)
- Use lots of strategies to control humidity, such as checking pipes, hoses and connections for condensation or water, and fixing water leaks. You can also remove mould, and repair cracked tiles, grout and caulking around your bathtub, sinks or shower. Even drying wet laundry outside helps.
- Use less chemical-heavy cleaning products, and don’t store paint, glue, bleach or pesticides and insecticides in your living quarters. Try to use cleaning solutions with less or no chemicals (scents included), and more natural ingredients.
- Use an exhaust fan vented to the outside when you’re cooking to reduce particles and gases.
If you decide to use cleaners with chemicals, use them according to manufacturer’s directions and in a well-ventilated area. Also consider disposing of partially full containers or old or unneeded chemicals safely because gases can leak from close containers too.
3. Clean mindfully and minimize your use of chemicals
Creating a regular cleaning routine can help keep pollutants at bay. Use a mix of methods like:
- Use a damp mop/cloth to clean dust and other particles from your floors, surfaces and even houseplants.
- Try to vacuum your floors and furniture once or twice a week to catch larger particles like pet hair and dust mites. Also choose a vacuum with a high-efficiency particle air (HEPA) filter to trap smaller particles.
- Vacuum your mattress and wash your bed sheets in hot water once per week. And use a mattress and pillow protector to reduce dust mites.
- Use an exhaust fan in the kitchen, washroom and laundry areas.
- Minimize clutter to reduce spots for dust and other pollutants to gather.
4. Use a HEPA filter wherever you can
High-efficiency particle air (HEPA) filters can trap small particles and reduce contaminants such as pet dander, pollen and dust mites. Use HEPA filters in your furnace, vacuum cleaner, or buy a free-standing air purification and filtration unit. HEPA filters capture various sized particles within a multi-layered netting usually made out of very fine fiberglass threads.
To choose an air purifier:
- Check for a clean-air delivery rate (CADR) rating of at least 240.
- Pick a model designed for larger area than the one it’ll be used in so that your unit will operate on a lower, quieter setting.
- Look for an Association of Home Appliance Manufacturers (AHAM) Verified mark.
- Make sure you’re buying a true HEPA filter. The industry standard is that the unit should be able to remove at least 99.97% of particulates measuring 0.3 micron diameter in a lab setting. Make sure you verify this by checking the manufacturer’s description.
Other types of filters like activated carbon can also be used to help clean your indoor air. Carbon filters can absorb some odour-causing molecules and may tackle some gases, and are even used in organic waste bins.
5. Use your central HVAC system to your advantage
If your home uses a centralized mechanical heating, ventilation and air conditioning (HVAC) system with built in duct work, upgrade your system to use a HEPA filter. These forced air systems are great for drawing in and treating outdoor air and circulating it around your home. Particulate matter can get trapped in your air ducts and recirculated around your home. Get your ducts cleaned from time to time to make sure clean air is circulating around your home. Replace and clean filters regularly and keep the system well maintained, so that it can perform at its best.
Conclusion: Keep your indoor air clean with natural ventilation and intentional choices
We hope this list gives you some ideas for simple changes to improve your indoor air quality today. If you came to this post to figure out which plants may do the trick, at least now you know that opening some windows might be all you need. It’s also important to be intentional about what kinds of products and home systems you use indoors.
Do you know of more ways to keep your indoor air clean? Let us know in the comments below:)