You've done extensive research on tools to prepare for the next wildfire, but the air is currently filled with smoke and you're missing some of the items on that list (like air purifiers). requires this temporary tool. Fixing it may alleviate the immediate situation.
In 2018, I tested a common claim. By attaching a furnace/HVAC filter to a standard box fan, you can create a handy DIY air purifier. We taped a 20 x 20-inch Honeywell FPR 9 filter to a Lasko 20-inch box fan and ran the combination in his standard 35-minute, five-game test in a 200-square-foot New York test space. Fans are high. And you know what? It worked, reducing the initial particle load by 87% in his 35 minutes in the medium. Although this doesn't come close to his 99% reduction that our water purifier achieved on high settings, the results were better than expected.
Some caveats apply.
As with any dedicated air purifier, we were careful to seal the entire area around the filter with clear, strong duct tape, as any gaps would allow unfiltered air to pass through. You should do the same if you try this hack.
Most box fans aren't designed to withstand the extra workload of forcing air through a filter, so this hack is unlikely to be a long-term solution to your air quality problem.
And in the long run, a fan and filter combination will cost more than a purifier. Fans are much less energy efficient than the purifiers we recommend, and HVAC filters have a shorter lifespan. Most of them rely on electrostatic attraction to trap particles efficiently, so their efficiency drops sharply when they become clogged (in fact, they are used in water purifiers where they become more efficient). HEPA filters). This means you should replace your fan filter at least every few months and in the event of an air quality crisis.
But if you're facing an air quality emergency, like a localized wildfire or burning your dinner under the broiler, and even though you have a box fan, tape, and the right kind of filter, you don't have an air purifier in hand. If you don't have time to put it in, it's worth a try.
Check out our guide to the best air purifiers for more details, information on how we tested them, and which air purifiers we recommend if you want something more sophisticated than a fan and filter rig.