Ever since the arrival of COVID-19, there has been a major shift in the level of focus around indoor air quality (IAQ) from building operators, designers and code officials. The most common strategy for both new and existing buildings to improve IAQ has been to introduce more fresh air whenever and wherever possible. However, this strategy is based on a key assumption which rarely gets checked:
‘Outside Air = Clean Air’
The wildfire events which occurred in Quebec throughout June 2023 have provided an eye watering reality check for Ontarians and many others. Fresh air may not be quite as ‘fresh’ as we are expecting it to be. In fact, Toronto was registered to have the worst air quality worldwide at one point in summer 2023.
Wildfire smoke is a complex mixture of airborne particulate matter (PM), as well as vapors and gases produced by incomplete combustion. While these contaminants may vary by event, test data from recent wildfire events has shown that the primary contaminants of concern include:
- PM2.5 – Fine Particulates Matter (<2.5 µm in diameter)
- PM1.0 – Ultra-Fine Particulate Matter (<1.0 µm in diameter)
- Semi-volatile organic compounds (SVOC’s)
Hourly PM2.5 readings published by Air Quality Ontario for Downtown Toronto between June 28th to 30th were consistently well above 35 μg/m3 and peaks above 160 μg/m3. This was the time period during which the wildfire smoke was most potent in the Toronto area. For reference, the table below outlines the risk levels associated with varying concentrations of PM2.5 over a 24-hour exposure period. While the data reflects PM2.5 levels, ultrafine (PM1.0) particles are considered to be the most dangerous of what is in the air.
|
Concentration Level |
Health Impacts: |
|
PM2.5 ≤ 12 μg/m3 |
Healthy with no risk of exposure |
|
PM2.5 ≥ 35 μg/m3 |
Unhealthy; increased risk for people with existing breathing issues (ie. Asthma) |
|
PM2.5 ≥ 50 μg/m3 |
Extreme risk to health and potential premature mortality |
To protect building occupants from smoke during wildfire events industry guidelines recommend upgrading filtration to MERV 13 or higher. MERV 13 filters are recognized as the lowest efficiency filter which is performance tested to for removal efficiencies of particle sizes 0.3 µm to 1.0 µm.
A better way to address both the fine and ultrafine particulates would be to consider the use of polarized media technology. Polarized media air cleaners are able to provide up to MERV 15 performance with very high removal efficiencies for coarse (PM10), fine (PM2.5) and ultrafine particles (PM1.0). With the ability to effectively remove ultra-fine particles, these air cleaning systems are also able to remove gas-phase contaminants which have adsorbed on the surface of these particles. Biological contaminants (eg. mold, bacteria and viruses) which are also often transmitted via the ultra-fine particles found in recirculation air can also be addressed with the help of polarized media air cleaners.
The data provided in the charts below demonstrate the effectiveness of the DynamicAQS V8 filtration system at maintaining extremely low PM2.5 and PM1.0 levels during a wildfire event.
When applied correctly, a polarized media air cleaning system can be utilised to significantly improve the indoor air quality for occupants year-round. Additionally, these air cleaning systems offer significant reductions in operating and maintenance costs via extremely low operating air pressure drops and unmatched dust loading capacity.
Reach out to your HTS contact for more information relating your specific application.