For Home For Pro

In this discussion, we explore indoor air quality (IAQ) with licensed architect Scott Farbman. With a Master’s degree in architecture and building science training from the Passive House Institute US, Scott has been professionally interested in IAQ for a while now. The time spent at home during the COVID-19 pandemic with a compromised immune system made him into an IAQ enthusiast though. 

Armed with a collection of indoor air quality monitors, extensive IAQ measurement experience, and a solid foundation in building design, Scott shares his journey and insights with Aranet. The following conversation delves into the complexities of IAQ, offering a practical look into the strategies that enhance the air we breathe in our spaces. 

Personal Journey to Improved Indoor Air Quality

Like many of us, Scott began prioritizing indoor air quality around 2020 when working from home became the norm for him and his spouse. Spending roughly 20 hours a day inside their home sparked his curiosity about the health of their environment. 

“We quickly noticed our CO2 levels were high, especially at night when we’d close the bedroom door. It builds up over time,” he observed when measuring the IAQ at home. Nightly, CO2 in the bedroom reached 1800 ppm (parts per million), prompting Scott and his spouse, Dr. Caroline Antler, a PhD and clinician-scientist, to research alternative solutions. Scott adds that “Caroline’s scientific training and background in data analysis has been crucial in evaluating existing research and comparing the data across the various IAQ devices and platforms”. 

Experimenting with IAQ monitoring devices, they discovered the need for more kitchen ventilation during and after cooking. “I’ll make sure that we’ve got some windows open if the outdoor air quality is good and that the kitchen exhaust is running for the proper amount of time to make sure that the air gets changed over. I’m much more sensitive to how I set up the space and how the space reacts over a period of time now.”

With additional time and measurements, Scott and Caroline realized a more significant change was necessary. To maintain continuous fresh indoor air quality, they decided to retrofit the ventilation system. Together, they installed an energy recovery ventilator (mechanical ventilation with heat recovery – MVHR), bringing in fresh filtered air constantly to keep CO2 levels low.

“Now it rarely goes above 600 ppm [CO2], so it’s been cut dramatically. It’s almost as good as being outside,” Scott reports.

The Dangers of Poor Outdoor Air Quality

As we unravel the complexities of indoor air quality, acknowledging the external environment becomes imperative. According to Scott, making strategic ventilation adjustments in response to outdoor air conditions is crucial for ensuring optimal IAQ.

“In school, we were taught that natural ventilation is the golden sustainability strategy.  Living in a densely populated city, I can no longer support this. The volatility of outdoor air quality, whether from traffic pollution or wildfire smoke, makes bringing fresh air in through windows a risky decision. In North American urban settings, natural ventilation is becoming less reliable. I am a huge proponent of filtered mechanical ventilation now. It is what I would recommend for nearly every setting and still allow for natural ventilation, but only when outdoor conditions are appropriate,” he explains.

Monitoring outdoor air quality is typically conducted by national or regional government programs. People can access real-time data and forecasts on sites such as:

  • for air quality data in the United States, including real-time air quality maps and forecasts;
  • offering a visual map of real-time air quality index in different regions worldwide;
  • providing a live world air pollution and air quality index (AQI) interactive animated map, combining PM2.5 data from public government sources, air quality stations, and their community;
  • for hyper-local and real-time air quality data.

While viewing this data offers a general sense of natural ventilation health in your area, Scott emphasizes another consideration. Depending on the location of the nearest public monitoring station, the provided data may sometimes be too general, missing hyper-local impacts from a city or regional-level air quality report.

“I’ve been tracking and comparing my hyper-local data with regional data, and it can vary substantially. It could be as simple as my neighbor starting up their truck in the morning and it running for 30 minutes next to us, or my neighbor on the other side having a fireplace going because it’s really cold out,” Scott explains. 

Assessing these risks can be facilitated by an outdoor air quality monitor or by adopting a more mindful approach to your surroundings. “I think it really depends on who you are and what the situation is,” he adds, noting that individuals may vary in their attention to these factors based on health concerns, environments, and other factors. 

Aranet4: A Portable Game-Changer

Aranet4 HOME

Having the home environment in check, it was time to turn the gaze outwards. This was especially important because both Scott and his spouse are disabled, meaning their risk of getting sick and falling ill more severely is higher than normal. So, they got themselves an Aranet4. 

“Our primary purpose for getting the Aranet4 was to bring it with us to help inform the decisions we would make to protect ourselves in public settings. I think it being portable was an absolute game-changer for the indoor air quality device industry too,” Scott shares.

Typically, 1000 ppm is the threshold for problematic indoor air quality, prompting actions to improve ventilation. However, individuals with chronic health conditions, like Scott, may have different needs, making an indoor air quality monitor invaluable. 

“750 ppm is my threshold for a change or a reconsideration of what’s happening in that space or what I’m doing. It also depends on how long I’m going to be there. If I’m just moving in quickly and I see a high number, I might tell myself, OK, get in there and get out, don’t linger,” Scott shares his approach. 

He adds that if the air quality went above 1000 ppm in a public or shared space, it would encourage him to either leave the space immediately or see if the situation can be quickly improved. 

“Can we open some windows and turn on some bath fans? If we’re going to have people over for a prolonged period of time and the CO2 isn’t where I’d like it to be, maybe that tells you we need to get the HEPA filter in here closer,” he elaborates. 

While Scott’s approach is driven by his health needs, he emphasizes the broader impact, urging awareness of indoor air quality for everyone. “I want other people to be aware that you don’t have to have chronic health conditions for this [poor IAQ] to be a potential problem. It could affect anyone,” he reasons. 

CO2: The Key Indicator for Indoor Air Quality

Drawing on his wealth of expertise in measuring indoor air quality and optimizing building design for better air, we sought Scott’s advice on where to begin for those interested in the air quality around them. He agrees with the industry standard of using CO2 as a proxy for the overall indoor air quality. 

“CO2 is kind of the go-to measure to get a quick sense of overall indoor air quality at least qualitatively. If CO2 is very high, that typically means you either have a densely populated space per floor area or you’ve got not enough outdoor air coming in to flush and dilute the space. So I would say CO2 is definitely the easiest to convert into an evaluation of IAQ at home,” he explains. 

Scott emphasizes the transformative impact of carrying a CO2 monitor like Aranet4. It not only informs individuals about their air quality but also empowers them, creating a ripple effect in the public and commercial sphere.

“There’s new pressure on building owners, public spaces, retail spaces etcetera, to do better because of the amount that individuals are monitoring with their own devices to hold them more accountable,” Scott shares, adding that Aranet4 has been a big part of this shift.

Looking for Solutions on a Larger Scale

Another shift that Scott has observed in his professional journey is the growing equilibrium between IAQ and energy efficiency within buildings. What was once a binary debate is now in search of a more proportional middle ground.

“People didn’t want to invest in indoor air quality measures because it had a direct conflict with energy efficiency. You would have to spend more energy and money space conditioning the outdoor air before you introduced it into the building,” Scott remembers. 

To make that shift more permanent, it is important to measure IAQ more routinely. Otherwise, it’s hard to grasp just how bad the indoor air quality can be in a lot of places many people occupy daily.

“There’s still a lot of resistance to doing it at the commercial level, and I think the big concern, which is unfortunate, is building owners are worried about liability if they display their indoor air quality and it’s not good and then they’re going tobe on the hook for repairing it or making it better,” Scott comments. 

Designing buildings with air quality in mind is a way to prevent such problems in the future. For the buildings already in place, the solution could be retrofitting or looking for more creative solutions. “If things can’t be solved at the building system level, then decentralized systems, like plug-in HEPA filters, may need to be explored so that specific spaces can maintain high levels of air quality,” Scott mentions as an example. 

In such cases, it becomes even more important to measure the IAQ to find out the problem areas and types (humidity, temperature, CO2 and others) before it’s possible to fix them. “You can’t manage what you don’t measure,” Scott concludes, emphasizing the importance of a data-driven approach in ensuring healthier built environments.


As we bring our conversation with architect Scott Farbman to a close, the Aranet team thanks him for sharing valuable insights and guiding us toward healthier indoor spaces. May these revelations empower everyone to make mindful choices and foster well-ventilated environments, enriching not only our homes and shared spaces but also our overall well-being.

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