Prepping for Wildfire Smoke Season

8 min readMay 14, 2019

In Seattle we’ve had an unwelcome visitor the past few summers — smoke from wildfires burning in the Pacific Northwest. You might recall lovely photos such as this one from last summer. What will you do when the wildfire smoke returns along with the evil red eye?

Climate change is leading to more fires, and weather patterns are pushing some of that wildfire smoke toward Seattle. As a resident I want to bury my head in the sand and pretend the problem doesn’t exist. It’s easy to forget about the summer smoke as we slog through our nine months of drizzle. Maybe it happened once or twice but it probably won’t happen again. Right?

This might be the new reality for Seattle. We need to adapt. How can we protect ourselves from the many hazards of wildfire smoke season? In this post I’ll outline the four M’s for dealing with wildfire smoke — Mitigate, Monkey-Wrench, Monitor and Migrate.

Mitigate

During peak smoke in Seattle last year, it was impossible to buy an air purifier or filter. The stores were filled with frantic customers wandering the empty aisles in search of air filters. I personally tried Home Depot, Lowes, Target, and Fred Meyer during my vain search for a decent air filter.

This year I’m doing something different. I’m preparing my home now so I don’t have to scramble in August. I’ve spent countless hours reading up on air filtering and I’m summarizing the best bits right here in this post.

Air Purifiers

An air purifier circulates air in your house, running the air through a filter to remove smoke and other particles. You’ll want to get an air purifier that’s big enough for your room, and uses the right filter to capture the smoke particles as the air is pulled through the machine.

As part of my prep this year, I bought air purifiers for several rooms in my house. As usual, Wirecutter has a great article on air purifiers. Based on their recommendation I picked up the following

I own these.

Coway AP-1512HH Air Purifer for our daughter’s small bedroom
Coway Airmega 300 for our large kitchen

These machines are amazing. The build quality is immediately obvious when you remove them from the box, especially compared to cheap air purifiers I’ve owned in the past. They feel solid and snap together in a pleasing way. It feels like unboxing an iPhone.

Pro tip #1 — Measure your room before buying an air purifier. You won’t be able to clean the air in your whole house with a small purifier.

Pro tip #2 — Don’t bother paying extra for air purifiers that come with “apps” or integrate with your phone. These junky features are unlikely to help you when wildfire smoke strikes, and buggy apps might actually get in the way.

Pro tip #3 — When you buy a new air purifier, you have to remove the plastic around the new air filter inside. It sounds obvious, but don’t forget! Otherwise, you won’t be getting any filtering whatsoever.

Pro tip #4 — Don’t forget to change the filter in your purifier every few months. This expense adds up over time, and it’s part of the reason why an air purifier’s initial price is relatively cheap. Give away the razor, sell the blades.

HVAC Filters

We retrofitted our home with AC a few years ago to take the sting out of our increasingly hot Seattle summers. Our house wasn’t built with ducts, but we were able to jam the AC into the attic and drop vents into the bedrooms upstairs. I wasn’t thinking about smoke at the time, but it’s easy to slip in better filters. This goes a long way toward keeping the house free of smoke.

An HVAC system pushes warm or cold air throughout your house. The filters that came with the unit are probably cheap meshes intended to keep out harmful dust and hair. Purify the air in your house by upgrading to higher quality filters.

The most common rating for air filters is the MERV systems. A MERV 8 can filter out large particles, but you’ll need to upgrade your filters to a higher MERV to remove the small particles found in smoke. With MERV 12 I didn’t notice any wildfire smell in my house.

I use MERV 12 Nordic Pure filters, which are highly ranked on Amazon and also scored well with Wirecutter. The hardest part was figuring out the correct filter dimensions, since each return vent is different. Measure first and when in doubt try to find the exact measurements for the filter, which will differ from the advertised size by a small amount. This turned out to matter in my case.

Here’s the MERV chart. Depending on circumstances, this year I might bite the bullet and go all the way to MERV 13 or 14 for peak season.

I’d also happily use Filtrete 1500 filters if I could find the right size for my vents. Naturally, big companies like 3M try to use their own ranking system. If you poke around a bit you’ll see that Filtrete’s MPR 1500 ranking is pretty similar to MERV 12.

Pro Tip — Fresh Chalk can help you find a great HVAC Contractor if you get stuck.

Monkey-Wrench : DIY Box Fan Air Purifier

There’s actually a cheap and cheerful way to tackle noxious wildfire smoke. When all else fails, you can build a cheap air purifier using a 20x20 box fan, a Filtrete 1500 20x20 filter and some duct tape. Watch out, though — when wildfire season strikes all the stores will be sold out of box fans and air filters. I can’t stress this enough. Prepare now if you want clean air later. You are not the only one in Seattle with this idea.

This hack was originally proposed by this official looking fellow from UMich:

The video is an epic four minutes, but I can save you the trouble:

Tape the filter to the fan
There is no step two

The most important thing is to attach the filter to the BACK of the fan so the fan sucks the filter ever closer toward the spinning bits instead of blowing the filter off. Also make sure that you flip the filter so that the arrows are POINTING TOWARD the fan.

Your homebrew unit will look like this:

I frantically built three of these last summer when I couldn’t find the proper filters for my HVAC system. The verdict? These worked pretty well! When I peeled off the filters at the end of the season, the pristine white filters were stained a sooty black. Think of all the lung junk I avoided with my DIY purifiers.

Pro tip — If your local hardware store is sold out of box fans, you might be able to get them on Amazon Prime Now. Worked for me.

Monitor

Let me refresh your memory of late August 2018. In the red and purple areas, we mostly huddled inside. People who were more sensitive wore respirators. Does this ring a bell?

For a two week period in August I was glued to my phone, refreshing various web sites and apps in a vain attempt to understand what was happening to my city. Here are the best web sites for checking current air quality and monitoring wildfires:

In peak season some of these sites were slow or inaccessible. Hopefully they’ve been upgraded this year. If not, try to check first thing in the morning before everyone wakes up. Most of the data is coming from the same place (NOAA), but at least there are a variety of ways to see it.

I particularly liked the NEIS Data Visualization. I was hypnotized watching lines of toxic red smoke jet into Seattle.

Migrate

When the air quality plummeted in Seattle, people started to get desperate. We kept our kids and pets indoors, with the windows and doors sealed. It was unpleasant. Seattle summers flash by in an instant, and it’s painful to get trapped by smoke.

One option if you have the flexibility — plan a vacation for the last few weeks of August when wildfire smoke is likely to peak. If the smoke invades Seattle again, you’ll feel like a genius. You will experience a secret joy breathing clean mountain air instead of stewing at home in the toxic smog. If Seattle ends up with clear skies, at least you’ll get to spend some quality time with your in-laws.

How does one go about planning a wildfire vacation? That’s easy — head for green. Take a peek at historical smoke charts from last year:

Note the relatively clear air east of the rockies. The midwest looks pretty good, and New England is untouched. I wouldn’t normally go to Florida in August, but it could be the perfect time for a Disney trip.

With a bit of foresight you might be able to get a great vacation and beat the smoke at the same time.

Looking Ahead

Each year, Seattle slides gratefully from drizzly spring into pure blue summer. We race outside and turn our faces upward for our brief allotment of sun. Sadly, wildfire smoke might be the new reality for the PNW. With a little bit of foresight, we can easily adapt our homes to weather the smoke.

Feel free to send me your own wildfire tips, which we will include in this post!