More Thoughts And Strategies For Managing Wildfire Smoke And Problematic Air Quality

In 2020 we had a bad wildfire smoke year with days of record-high heat and poor air quality. It was especially problematic in the greater Seattle area and Pacific Northwest (PNW) where most people don’t have air conditioning. I previously wrote about some of our strategies here, such as box fans with furnace filters; additional air purifiers; and n95 masks. All of those are strategies we have continued to use in the following years, and while our big HEPA air purifier felt expensive at the time, it was a good investment and has definitely done what it needs to do.

This year, we got to September 2022 before we had bad wildfire smoke. I had been crossing my fingers and hoped we’d skip it entirely, but nope. Thankfully, we didn’t have the record heat and the smoke at the same time, but we did end up having smoke blowing in from other states, and then a local wildfire 30-40 miles away that has been making things tricky for several days on and off…several different times.

I’ve been training for an ultramarathon, so it’s been frustrating to have to look not only at the weather but also the air quality to determine how/when to run. I don’t necessarily have a medical condition that makes me higher risk to poor air quality (that I know of), but I think there’s some correlation with being allergic to a lot of environmental things (like dust, mold, trees, grass, etc) that makes it so that I also am more sensitive to most people I know to poor air quality.

Everyone’s sensitivity is different, but I’ve been figuring out thanks to multiple stretches of up and down AQI that my threshold for masking outside is about 50 AQI. If it gets to be around 100 or above, I don’t want to be walking or running outside, even with a mask. And as it gets above 150 outside, it becomes yucky inside for me, too, even with the doors and windows closed, the vents on our windows taped shut, and air purifiers and box fans etc running. My throat was scratchy and my eyes hurt, and my chest started to feel yucky, too.

It got so bad last week that I took a small, portable mini air purifier that I had bought to help mitigate COVID-19 exposure on planes, and stuck it in front of my face. It noticeably made my throat stop feeling scratchy, so it was clearly cleaning the air to a degree. On the worst days, I’ve been sitting at my desk working with the stream of air blowing in my face, and I’ve also been leaving it turned on and pointed at my face overnight.

This is kind of a subjective, arbitrary “this helps”, but today we ended up being able to quantify how much it helps to have our big air purifier, box fans with furnace filters, smaller air purifier, and the mini air purifier. Scott ordered a small, portable PM2.5 / PM10 monitor to be able to see what the PM2.5 and PM10 levels are in that exact spot, as opposed to relying on IQAir or similar locally reported sensors that only tell us generally how bad things are in our area.

It also turned out to be useful for checking how effective each of our things are.

It turns out that our box fans with furnace filters taped to the back are most effective at fan speed “1” (they all go up to 3), probably because putting it up to 3 is prone to stirring up dust from the floor (despite robot vacuuming multiple times of day) and increasing PM10 levels. A box fan with 2” MERV 10 filter taped to the back doesn’t affect the already-low PM2.5 levels indoors; on fan level 1 the PM10 gets reduced to zero as long as it’s not pointed at the carpet and stirring up dust. So while it doesn’t help with smoke, these fans are good with increasing circulating air (so it feels cooler) and getting rid of the dust and cat hair that I’m allergic to.

The big HEPA air purifier we bought has a connected app that tells us the PM2.5 levels, and our portable PM2.5 monitor confirms that it’s putting out air with a PM2.5 level of 0. Yay! This sits in our kitchen by our front door, so it helps clean the smoky hallway air coming inside.

A cat sticking it's face toward the phone camera. Behind the cat, a portable PM 2.5 / PM 10 air monitor sits on the floor by a door to measure incoming air.

The hallway air is TERRIBLE. The hallway opens directly to the parking garage, and is usually about as smoky as the outdoor air: it only has a single A/C duct for the whole building, which isn’t always running. The stairwell leading outside is a little cleaner than the hallway and outside. (So I’m glad we have our best air purifier situated to take on the air coming in when we open the hallway door). So we won’t be spending time exercising in the hallways, either; with that level of air quality you might as well be outside anyway, because we need to be masked either way.

The other purifier we have is a smaller purifier. I have it sitting on the counter in our bathroom, because the air exchange to outside is really reduced compared to what it should be (and the building management doesn’t seem very interested in trying to figure out how to fix it). That purifier gets PM2.5 down from 4 to 1 ug/m^3, or about a 4x improvement! Which is pretty good, although not quite as good as the big purifier in our kitchen/entry. Since it’s small enough to sit on a desk or bedside table and blow clean air at me where I’m working or sleeping, we decided to order 2 more of these smaller purifiers for my office and our bedroom, since the box fans take care of PM10 but not the PM2.5.

PM2.5 and PM10 readings from the portable monitor, from on top of the air purifier; next to my office; next to a box fan with filter; in the hallway; in the stairwell; and outside. This is roughly in order of best (inside over the air purifier) to worst (hallway and outside; the stairwell is slightly better than the hallway).

Since the portable air quality monitor would be hard to fit inside his mask or his mouth, and impossible to read there, Scott also held up the PM2.5/10 monitor to the exhaust valve on his n95 mask (note: not all our n95 masks our valved but the valved ones are good for wildfire smoke and managing temperature levels inside your mask when exercising) while outside, and the average PM2.5 level there is about half that of the ambient air. Since about half the time he’s breathing in (and the meter is sucking in outside air) and the other half of the time he’s breathing out (so it’s getting the mask-filtered air he inhaled and then exhaled), this suggests that the mask is doing it’s job of reducing PM2.5 levels he’s breathing inside the mask to very low levels (probably about the same as our very clean indoor air).

He also held it over the small air purifier that I’ve been keeping my face over. It, too, reduces PM2.5 down to about 2 – so not as good as the bigger purifiers, but a ~2x improvement over the ~4 in the ambient air that I would otherwise be breathing.

TLDR:

  • Box fans with MERV 10 filters are great for allergens and PM10, but don’t noticeably reduce the PM2.5. Higher MERV filters might do better, but are very expensive, and probably less cost-effective than a purifier with a proper HEPA filter.
  • Small and big air purifiers work well for reducing PM2.5.
  • N95 masks are effective at drastically reducing the PM2.5 you’d be exposed to outside.
  • If you’re like me and are bothered inside when the air quality outside is bad, additional air purifiers (small or big) might help improve your quality of life during these smoky days that we are increasingly getting every year.

How to deal with wildfire smoke and air quality issues during COVID-19

2020. What a year. We’ve been social distancing since late February and being very careful in terms of minimizing interactions even with family, for months. We haven’t traveled, we haven’t gone out to eat, and we basically only go out to get exercise (with a mask when it’s on hiking trails/around anyone) or Scott goes to the grocery store (n95 masked). We’ve been working on CoEpi (see CoEpi.org – an open source exposure notification app based on symptom reports) and staying on top of the scientific literature around COVID-19, regarding NPIs like distancing and masking; at-home diagnostics like temperature and pulse oximetry monitoring, prophylactics and treatments like zinc, quercetine, and even MMR vaccines; and the impact of ventilation and air quality on COVID-19 transmission and susceptibility.

And we live in Washington, so the focus on air quality got very real very quickly during this year’s wildfire season, where we had wildfires across the state of Washington, then got pummeled for over a week with hazardous levels of wildfire smoke coming up from Oregon and California to cover our existing smoke layer. But, one of our DIY air quality hacks for COVID-19 gave us a head start on air quality improvements for smoke-laden air, which I’ll describe below.

Here are various things we’ve gotten and have been using in our personal attempts to thwart COVID-19:

  • Finger pulse oximeter.
    • Just about any cheap pulse oximeter you can find is fine. The goal is to get an idea of your normal baseline oxygen rates. If you dip low, that might be a reason to go to urgent care or the ER or at least talk to your doctor about it. For me, I am typically 98-99% (mine doesn’t read higher than 99%), and my personal plan would be to talk to a healthcare provider if I was sick and started dropping below 94%.
  • Thermometer
    • Use any thermometer that you’ll actually use. I have previously used a no-touch thermometer that could read foreheads but found it varied widely and inconsistently, so I went back to an under the tongue thermometer and took my temperature for several months at different times to figure out my baselines. If sick or you have a suspected exposure, it’s good to be checking at different times of the day (people often have lower temps in the morning than in the evening, so knowing your daily differences may help you evaluate if you’re elevated for you or not).
    • Note: women with menstrual cycles may have changes related to this; such as lower baseline temps at the start of the cycle and having a temperature upswing around or after the mid-point in their cycle. But not all do. Also, certain medications or birth controls can impact basal temperatures, so be aware of that.
  • Originally, n95 masks with outlet valves.
    • Note: n95 masks with valves cannot be used by medical professionals, because the valves make them less effective for protecting others. (So don’t freak out at people who had a box of valved n95 masks from previous wildfire smoke seasons, as we did. Ahem.) 
    • We had a box we bought after previous years’ wildfire smoke, and they work well for us (in low-risk non-medical settings) for repeated use. They’re Scott’s go-to choice. If you’re in a setting where the outlet valve matters (indoors in a doctor’s/medical setting, or on a plane), you can easily pop a surgical/procedure mask over the valve to block the valve to protect others from your exhaust, while still getting good n95-level protection for yourself.
    • They were out of stock since February, but given the focus on n95 without valves for medical PPE, there have been a few boxes of n95 masks with outlet valves showing up online at silly prices ($7 per mask or so). But, kn95’s are a cheaper per mask option that are generally more available – see below.
    • (June 2021 note – they are back to reasonable prices, in the $1-2 range per mask on Amazon, and available again.)
  • kn95 masks.
    • kn95 masks are a different standard than US-rated n95; but they both block 95% of tiny (0.3 micron) particles. For non-medical usage, we consider them equivalent. But like n95, the fit is key.
    • We originally bought these kn95s, but the ear loops were quite big on me. (See below for options if this is the case on any you get.) They aren’t as hardy as the n95s with valves (above); the straps have broken off, tearing the mask, after about 4-5 long wears. That’s still worth it for them being $2-3 each (depending on how many you buy at a time) for me, but I’d always pack a spare mask (of any kind) just in case.
      • Option one to adjust ear loops: I loop them over my ponytail, making them head loops. This has been my favorite kn95 option because I get a great fit and a tight seal with this method.
      • Option two to adjust ear loops: tie knots in the ear loops
      • Option three to adjust ear loops: use things like this to tighten the ear loops
    • We also got a set of these kn95s. They don’t fit quite as well in terms of a tight face fit, but these actually work as ear loops (as designed), and I was able to wear this inside the house on the worst day of air quality.
  • Box fan with a filter to reduce COVID-19 particles in the air:
    • We read this story about using an existing AC air furnace filter on a box fan to help reduce the number of COVID-19 particles in the air. We already had a box fan, so we took one of our spare 20×20 filters and popped it on. I’m allergic to dust, cats (which we just got), trees, grass, etc, so I knew it would also help with regular allergens. There are different levels of filter – all the way up to HEPA filters – but we had MERV 12 so that’s what we used.
  • Phone/object UV sanitizer
    • We got a PhoneSoap Pro (in lavender, but there are other colors). Phones are germy, and being able to pop the phone in (plus keys or any other objects like credit cards or insurance cards that might have been handled by another human) to disinfect has been nice to have.
    • The Pro is done sanitizing in 5 minutes, vs the regular one takes 10 minutes. It’s not quite 2x the price as the non-pro, but I’ve found it to be worthwhile because otherwise, I would be impatient to get my phone back out. I usually pop my phone in it when I get home from my walk, and by the time I’m done washing my hands and all the steps of getting home, the phone is about or already done being sanitized.
  • Bonus (but not as useful to everyone as the above, and pricey): Oura ring
    • Scott and I also both got Oura rings. They are pricey, but every morning when we wake up we can see our lowest resting heart rate (RHR), heart rate variability (HRV), temperature deviations, and respiratory rate (RR). There have been studies showing that HRV, RHR, overnight temperature, and RR changes happen early in COVID-19 and other infections, which can give an early warning sign that you might be getting sick with something. That can be a good early warning sign (before you get to the point of being symptomatic and highly infectious) that you need to mask up and work from home/social distance/not interact with other people if you can help it. I find the data soothing, as I am used to using a lot of diabetes data on a daily and real-time basis (see also: invented an open source artificial pancreas). Due to price and level of interest in self-tracking data, this may not be a great tool for everyone.
    • Note this doesn’t tell you your temperature in real time, or present absolute values, but it’s helpful to see, and get warnings about, any concerning trends in your body temperature data. I’ve seen several anecdotal reports of this being used for early detection of COVID-19 infection and various types of relapses experienced by long-haulers.

And here are some things we’ve added to battle air quality during wildfire smoke season:

  • We were already running a box fan with a filter (see above for more details) for COVID-19 and allergen reduction; so we kept running it on high speed for smoke reduction.
    • Basic steps: get box fan, get a filter, and duct tape or strap it on. Doesn’t have to be cute, but it will help.
    • I run this on high speed during the day in my bedroom, and then on low speed overnight or sleep with earplugs in.
  • We already had a small air purifier for allergens, which we also kept running on high. This one hangs out in our guest bedroom/my office.
  • We caved and got a new, bigger air purifier, since we expect future years to be equally and unfortunately as smoky. This is the new air purifier we got. (Scott chose the 280i version that claims to cover 279 sq. ft.). It’s expensive, but given how miserable I was even inside the house with decent air quality thanks to my box fan and filter, little purifier, and our A/C filtered air… I consider it to be worth the investment.
    • We plugged it in and validated that with our A/C-filtered air combined with my little air purifier and the box fan with filter running on high, we already had ‘good’ air quality (but not excellent). We also stuck it out in the hallway to see what the hallway air quality was running – around 125 ug/m^3 – yikes. Turns out that was almost as high as the outside air, which is I’ve had to wear a kn95 mask even to walk hallway laps, and why my eyes are irritated. example air quality difference between hallway and our kitchen. hallway is much higher.
  • Check your other filters while you’re on air quality monitoring alert. We found our A/C intake duct vent had not had the air filter changed since we moved in over a year ago… and turns out it’s a non-standard size and had a hand-cut stuffed in there, so we ordered a correctly sized one for the vent, and taped a different one over the outside in the interim.
  • The other thing to fight the smoke is having n95 with valves or kn95 masks to wear when we have to go outside, or if it gets particularly bad inside. Our previous strategy was to have several on hand for wildfire season, and we’ll continue to do this. (See above in the COVID-19 section for descriptions in more detail about different kinds of masks we’ve tried.)
  • 2022 update: I got a mini personal air purifier to try for travel (to help reduce risk of COVID-19 in addition to all other precautions like staying masked on planes and indoor spaces), but it also turned out to be beneficial inside during the worst of our 2022 wildfire smoke season. I had a slightly scratchy throat even with two box fans and two different air purifiers inside; but keeping this individual one plugged in and pointed at my face overnight eliminated me waking up with a scratchy throat. That’s great for wildfire smoke, and also shows that there is some efficacy to this fan for it’s intended purpose, which is improving air around my face during travel in inside spaces for COVID-19 and other disease prevention.

Wildfires, their smoke, and COVID-19 combined is a bit of a mess for our health. Stay inside when you can, wear masks when you’re around other people outside your household that you have to share air with, wash your hands, and good luck.