Kathleen McKee: Indoor air in the Salt Lake Valley is worse than you think

But there are some things you can do about it.

(Rick Egan | The Salt Lake Tribune) Smokey skies from wild fires in California, Oregon and Washington, effect the visibility and air quality in Salt Lake City, on Friday, Aug. 6, 2021.

I am a Salt Lake City physician and mother. I am concerned about the effects of poor air quality on my children’s health, my patients’ health and my own health.

Bad air is not just a lung issue. The particulate matter from wildfire smoke and winter inversions penetrates alveoli (the tiniest air sacs deep in the lungs) and enters the blood stream, where it can affect every organ in our bodies.

While the lung effects of polluted air such as a tight chest or asthma exacerbation are immediate and obvious, the effects on other organ systems are invisible until you look at the data that shows increased heart attacks, lower test scores, increased school absences and even increased mortality on bad air days. And while the effects of chronic exposure even to low levels of air pollution are still being studied — we know they are not good. The Lancet Countdown on health and climate change grimly lays out the tragic health risks for a child born today if we fail to respond to climate change, including air pollution.

Unfortunately, bad air is no longer an occasional Salt Lake occurrence. Rather, practically every summer day shows deteriorating air quality in the afternoon from ozone — catalyzed into existence by ever hotter temperatures. Add in the wildfires and, we’ve had round the clock poor air quality this entire summer. It’s not going to get any better in summers to come. These are the effects of exponential climate change and they are upon us now.

It’s tempting to think that keeping ourselves inside on the worst air days is sufficient. That is a falsely reassuring and woefully insufficient solution. Houses and commercial buildings are leaky enough that the bad air gets in very quickly. Yet there are simple steps we can take to clean the air in our homes, daycares, schools, gyms, offices, places of gathering and worship.

A recent article in The Salt Lake Tribune highlighted the myriad sources of indoor air pollution that require different mitigation strategies. However, when we are talking about cleaning the air of particulate matter coming from winter inversions or wildfire smoke, the most strongly recommended intervention is high-efficiency particulate air (HEPA) filters.

In a study done in Salt Lake City, portable HEPA filters were shown to significantly reduce the particulate concentration in the sleeping zone of a home during periods of air pollution. Additionally, HEPA filters remove viruses such as COVID-19 from circulation. (Note that a carbon filter is needed to trap ozone. A single portable filter unit can have both a HEPA and carbon filter.)

So why doesn’t every indoor space in Salt Lake have portable HEPA filters? In addition to cost, I think it’s because without an air quality monitor you can’t tell if the filter is working — and so you never know if the investment was worth it.

It’s only within the last few years that portable air quality monitors have become widely available. Prior to that time, the only data on air quality came from EPA operated sensors. Within Salt Lake County there are nine official sensors (e.g. at Hawthorne, Rose Park, Murray). There is no EPA operated sensor in Park City, although research sensors are beginning to capture the variable air quality in this Wasatch Back city. The EPA monitors measure PM 2.5 (or particulate matter 2.5 microns and larger), ozone, nitrogen oxides, carbon monoxide and sulfur dioxide. They cost tens of thousands of dollars and are quite large — thus it’s not feasible for these units to be deployed to measure indoor air.

Portable air quality monitors use different technology to measure air quality. It is true the lower-cost portable sensors are not as accurate as the EPA or research-grade sensors, and certain portable sensors perform better than others as established by the Air Quality Sensor Performance Evaluation Center. But the best performing of these portable sensors are good enough to figure out if your indoor air is trending better or worse, particularly during or after significant events like fireworks, wildfires and inversions. And they only cost a few hundred dollars. (Note that none of the most affordable sensors measures ozone.)

One sensor output I find particularly intuitive is a color-coding scheme that matches up with the EPA Air Quality Index ranging from green (good) to yellow to orange to red to purple to maroon (the worst air). (Salt Lake City reached maroon levels on August 6, earning us the distinction of having the worst air in the world that day.)

Twice in the last month I’ve seen proof that it’s hard for us to take action until we can “see” the bad air.

On bad air days when my kids’ daycares were keeping the children inside, both daycares were doing the right thing — but our portable air monitor showed the air was yellow to orange inside my kids’ classrooms. One daycare took the monitor and tested every room in their center. We were all surprised and saddened to find not a single “green” air room throughout the daycare.

We brought one of our HEPA filters and left the air monitor and filter at each daycare for a day. The teachers got to see the air quality turn from orange to yellow to green. This visual was very powerful. Obviously, no one wants to breathe bad air — but most people simply don’t realize the air they are breathing is a lot less clean than it could be. The air monitor allows real-time knowledge of air quality and can inform immediate changes in action (e.g.: shut windows, turn off swamp cooler, kick filters into turbo).

If both my kids’ daycares and our home all have non-green air quality without a portable HEPA filter, I’m guessing most other indoor spaces in our city have less-than clean indoor air as well. Thankfully, we have the technology to clean particulate matter and viruses including COVID-19 from indoor air.

Of course additional sources of indoor air pollution require different mitigation strategies, and those experiencing homelessness have no indoor air to clean. But being mindful of the complexity and inequity of our world, we still must start somewhere.

After a summer that has felt very out of control, I breathe (pun intended!) a little easier knowing my kids are sleeping and learning in green air. Here’s to facing the future together and using this fall to get ready for the coming winter inversions, and the smoke and ozone that will be back next summer.

Kathleen McKee, MD

Kathleen McKee, M.D., MPH, is a neurologist in Salt Lake City. She thanks Daniel Mendoza, Ph.D., and Denitza Blagev, M.D., for their expertise in crafting this commentary.

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