This podcast is airing while catastrophic wildfires are raging over the entire West Coast, and many of us have been living in air quality that is beyond the air toxics index. I have never thought so much about my HVAC system and the trade-offs of protecting my home from external particulate matter versus needing to ventilate my home. As a lung doctor, it is hard not to think about how much our buildings need to breathe just like we do. One person who makes it his job to study this is Dr. Elliott Gall, a scientist in the Department of Mechanical and Materials Engineering at Portland State University. He obtained his PhD in Civil Engineering from the University of Texas at Austin. He studies indoor air quality, including HVAC systems and understanding how air pollution enters and leaves our homes and other buildings where we live our lives.
I interviewed him on the podcast today, and was able to ask him many questions that have been so pertinent to my patients and to my family about how to keep ourselves as healthy as possible in the massive wildfires that are currently engulfing the West Coast. We talk about the general principles of indoor air quality and pitfalls in trying to buy air filters with all the misinformation and marketing out there. He gives concrete guidance on improving your indoor air quality, planning for future wildfire events, and what we can do to decrease their frequency and build resiliency. We also talk about different ways of monitoring the air, whether smell is sufficient, how Purple Air monitors fit in, etc.
One of the concerns he raised was about the gas phase compounds and including toxins like benzene that are also elevated. Importantly, our particulate matter filters do not address these gas phase compounds. He discusses strategies to address this, but also recognizes our limitations, particularly around carbon monoxide. These fires are raising these gases in our outside air, so we are limited in our ability to clear it from our homes.
As a lung doctor, I have been bombarded with questions and memes from social media about whether people should be boiling water with herbs and what options are helpful for maintaining good indoor air quality. We dive into this topic as well; he even did some experiments this morning in his house to see if boiling water was effective at meaningfully reducing PM2.5 (spoiler- it wasn’t).
Overall, it is hard to not think about the magnitude of the cost of these fires, not only in the toll on human life and property that has already occurred, particularly for those who have lost loved ones and homes directly due to fire, but also in the healthcare expenditures and economic devastation from those affected by the smoke itself, in addition to the costs that all of us will have to lay out to prepare our own homes for decreasing air pollution exposure. It has never been so clear to me that healthy air leads to healthy people and a healthy economy.
References: from Dr. Gall- @etgall on Twitter- follow for more!
- AHAM has some basic guidance on choosing an air cleaner
- ASHRAE has a great technical document on air cleaning and filtration (perhaps too technical for some, but loads of great info in much more detail that I could go into on the show)
- Your own home’s ventilation- challenging to find something on the basics and likely unique to various homes. Big thing to determine is whether your system recirculates air through forced air and ventilated by infiltration or via air exchange, etc. A few resources from energy.gov and EPA aren’t bad:
- DIY Air-Cleaner
- DIY air-cleaner on steroids:
- Selecting a higher MERV filter for your forced air system than you usually use is a bit more complicated and probably should be done with consult of an HVAC professional. Most systems can probably accommodate a MERV10-12 for a short period like a wildfire, but not all. Some more details on this: https://www.texairfilters.com/selecting-the-right-filter-to-improve-indoor-air-quality/
- General sources for IAQ
- https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality
- Harvard has a good website: https://forhealth.org/
- ASHRAE – American Society of Heating, Refrigerating and Air-Conditioning Engineers – formed by the merger in 1959 of American Society of Heating and Air-Conditioning Engineers (ASHAE) founded in 1894 and The American Society of Refrigerating Engineers (ASRE) founded in 1904. Working on home resiliency in wildfire prone areas.
