At the risk of sounding a bit doomsday, I think we need to face the fact that our buildings are a container for contaminants. These are released from the products we use every day. There is also off-gassing from most things we add to our house such as furniture and fabrics. Contaminants are even created in the process of lighting a candle or cooking a steak. Most newer homes exhaust this contaminated air outside and bring in new fresh air but a lot of older homes (like mine) just rely on air leakage as a means of exchanging the air. (can you expand this section?) As we become more mindful of creating healthier homes, air quality is something we, as homeowners and designers, should pay more attention to. Starting with reducing contaminants and remediating the air instead of just exhausting it outside into our immediate environments.
So let’s look at the basics. What are the biggest contributors to air quality and how do we mitigate them?
Particulate Matter
First let’s talk about particulates or particular matter (PM). Particulates are small solid or liquid particles in the air like dander, pollen, dirt, smoke, ash, viruses etc. Measuring particulates is most often used when determining exterior air quality. And those measurements are usually broken down based on the sizes of particulates (PM2.5 is looking at smaller particles 2.5 microns or less and PM10 is a measure of larger particles).
How do we manage particulate matter? Air filtration systems - although that isn’t going to be the answer to everything! Nonetheless, to filter out particulates in the air, we need air filters with MERV ratings that are either integrated into our air handling or heating system or come as part of a stand alone unit. Higher MERV ratings mean finer particles are being filtered out. And HEPA (High Efficiency Particulate Air) filters have a MERV rating of 17 or higher. However, you can’t just put a higher rated MERV filter in your furnace. It reduces air flow and can mess up your system. Check and see what the highest MERV filter your system can handle. For residential units, it is usually around 8-10 MERV. So, often additional stand alone units are required if you want to filter finer particles out of the air.
VOC's
Second on our list is Volatile Organic Compounds - or VOC’s - these are harmful often cancer-causing chemicals that get released into the air from our paint, flooring, furniture, fabric, hair products and cleaning products. Chemicals used in manufacturing and preservation like Formaldehyde, benzene and toluene etc. This is best dealt with by being aware of the VOC’s in the products we bring into our home. Selecting paint, varnishes, flooring and furniture that don’t give off VOC’s, or low amounts of them is a great start. Due to the surge of interest in healthier spaces, there are a lot of certification processes or product lists that specifically address VOC's. However, this interest has also led to a lot of greenwashing… making a product seem like it has a positive impact on the environment more than it really does. Look for declarations associated with LEED (a green building standard), that address the Living Building Challenge’s Red List or the Cradle to Cradle Basic Level Restricted Substances List. Especially, be careful of the formaldehyde content in the furniture you buy. Most furniture contains formaldehyde but many manufacturers like Ikea have been looking to reduce the amount.
You can exhaust these VOC’s outside with fans (for bathroom products) or your air handling system. You can also get stand alone units that trap the VOC’s with an activated carbon filter. For more aesthetically pleasing solutions, check out bio filtration systems like Ontario-based Respira (hyperlink the name). They filter out contaminants by drawing air through the plant roots which then trap and break down the VOC’s. Some biofiltration systems also use the soil to create an ecosystem that captures and breaks down VOC’s.
Inorganic Compounds
Thirdly, let’s look at inorganic compounds. This is things like nitrogen dioxide, ozone, and carbon monoxide that are created when we cook (even with induction), light a candle, use a printer, turn on the fireplace or anything with combustion. There are no residential air filtration system made to filter out carbon monoxide. Though there are studies that show that specific activated carbon filters can filter out some carbon monoxide as well as bio filtration systems. Additionally, filters with MERV 13 or above can filter out the smoke usually associated with Carbon Monoxide. However, there aren't filtration systems specifically designed to filter out inorganic compounds.
Monitoring is a great start. Understanding what and where these compounds are produced lets us segregate them at the point of origin and then exhausting them out. Kitchens should have exhaust fans. In offices, printing rooms should be enclosed and have their own exhaust fan. Combustion appliances that create a lot of Carbon Monoxide should be limited or even replaced. I’m sorry, wood fire places… I’ll miss you.
Radon
Fourthly, we’ll look at Radon. Radon usually gets singled out due to it's greater impact. It is the second leading cause of cancer after smoking. It is found in the ground and any basement or first floor space should be tested to see if there is Radon. You can buy detectors and can even rent them at local libraries, especially in areas with high amounts of radon like Kingston, ON (where we are located). Radon can’t be filtered out due to it being a Noble gas, (I don’t think I’ve seen that term used since First Year Chemistry). And Radon should be exhausted before it enters your home. This is usually done by collecting the gas underneath your basement floor slab and then expelling it out.
Adding an air monitoring system to your home will let you know what issues you are having. Most filtration systems with integrated monitors as well as standalone monitors make it too simple, such as using three coloured lights (think green/yellow/red). Make sure to get find a monitor system that differentiates between the different types of contaminants. As a side note, we didn't touch on CO2 but often these devices monitor CO2 because it gives a good indication of generally how well ventilated and filtered the air is.
If you are still awake and you’d like to know more about Air Quality (as this just scratches the surface,) I’d recommend checking out the Well Certification Standard. It is a certification system for buildings that look at creating healthier spaces. In their overview, they have a great set of references to applicable studies. There is also information on the health problems associated with the different contaminants as well as other air quality factors such as humidity and types of ventilation etc. And yes, I did read all those sections (not just the air one) and passed the exam. But don't worry, there isn't an exam at the end of this article.
https://v2.wellcertified.com/en/wellv2/air
And if you are interested, we designed our own modular biofiltration system for an architectural design competition called Breathe.
https://www.fabricaearchitecture.com/post/breathe
Jen Demitor, Owner and Architect at Fabricae Architecture and Art Ltd.
コメント