Can houseplants clean dirty air? Q&A answers this and more

Read this Q&A for a taste of what was discussed during the “HVAC: IAQ and IEQ” webcast

By Consulting-Specifying Engineer February 29, 2024
To help eliminate excess leakage of contaminated air, taping air handling unit (AHU) filter edges to prevent as much outside air (OA) leakage as possible helps ensure that all that air is passing over filter media to capture as much as possible that's at a building level. Courtesy: Consulting-Specifying Engineer

Some questions were directly addressed during the live event in November 2023. While watching the webcast HVAC: IAQ and IEQ is a much more complete overview, reviewing this transcript of the Q&A helps define the topic better. It has been edited for length and clarity.

The expert presenters are:

  • Garett Karalus, PE, CCP, Director of Engineering/Lead Commissioning Agent, IEA Inc., Brooklyn Park, Minnesota
  • Emmy Riley, CEM, BEAP, WELL Performance Testing Agent, Energy Engineering Team Leader & Account Manager, Cyclone Energy Group, Chicago
Garett Karalus, PE, CCP and Emmy Riley, CEM, BEAP, WELL Performance Testing Agent

Garett Karalus, PE, CCP and Emmy Riley, CEM, BEAP, WELL Performance Testing Agent

What’s the best approach in providing ventilation air? Is it a dedicated outside air unit or supplying outdoor air to multiple air handling units?

Garrett Karalus: Yes, in my experience, there are several different methods that provide adequate ventilation. I don’t think any of those strategies mentioned is necessarily better than the other. Ultimately, what really matters is just that the designer accounts for how the system is going to be operating after the building’s installed and any varying conditions that can impact it. Generally, what we struggle to resolve our design problems that maybe depend on certain pressures between return or exhaust or other air ducts.

And then if the design is set a certain way, there are sometimes design limitations for us to be able to commission it to where it will function properly. But ultimately the method, whether it’s one unit that’s sent to a bunch of fan coil units or outdoor air that’s 100% outside air to systems with partial outside air versus 100% dedicated outside air systems with the induction coil or induction units. We’ve seen both work and both can function when they’re properly designed and when they’re properly installed.

What is your experience in indoor air quality (IAQ) treatment using specific plants to reduce contaminants and add oxygen?

Emmy Riley: The most organized scientific information I’ve read about this is from the American Lung Association and their take. There’s a NASA study that’s commonly cited about having plants in a very, very controlled environment improves indoor air quality. The American Lung Association says it’s really a mixed bag. There could be some benefits in terms of increased oxygen, but you may be introducing things like mold and even from my own personal experience like little fungus gnats. Plants are not a primary means of improving indoor air quality, but consider plants as a way of maybe using them for an indoor environmental quality, feeling nicer about the space.

With the recent IAQ concerns regarding COVID and wildfires, has there been much attention to sick building syndrome and potential remedies to that?

Garrett Karalus: My company has been doing IAQ walkthroughs from long before the recent COVID issues and I think there’s been a general awareness of the elevated carbon dioxide (CO2) levels. It was astronomical after the pandemic. I think it’s been heightened since then and it’s the general awareness of it has improved, but even before we were doing that, there was awareness of the sick building syndrome within the industry, it just probably wasn’t quite as promoted and ultimately within the building and building owners.