Editor’s note: This article original ran in November of 2018, during a long fire seasons in which the Ranch Fire, River Fire, and the Camp Fire frequently left Mendocino County with terrible air quality.
WILLITS, 11/12/18 — It has been miserable outside for the past few days, and as air has a tendency to go everywhere, it’s been kind of bad indoors too. The tremendous amount of smoke from the Camp Fire in Butte County, has darken our skies and maybe out lungs. For a time last week Ukiah had the worst air quality in the country and among the worst on earth.
But air purifiers are kind of expensive, so if you’re looking for a budget solution, you can make your own, with a box fan and a furnace filter. We built one with a fan, filter, and duct-tape purchased at Mendo Mill, and it cost about $45.
But don’t take our word for it, check out this sciencey video from the University of Michigan — complete with a particulate counter, and a guy in a lab coat. (Scroll down for more air quality information.)
Remember if you put together one of these you want to use the finest filter. We found some 13 “Merv” filters at the hardware store, which are apparently fine enough to sift out smoke particulates.
And here is what our attempt at a purifier looked like after a couple of days, running indoors in Willits. Now, maybe this particular member of The Mendo Voice has a dusty house, but still, kind of gross.
Some readers reported building a similar purifier in Potter Valley and blackening them in a matter of days.
At the Mendo Voice we also tried a variation on this with a fine filter on the blowing side of the fan, and a courser filter to catch dust and dirt on the intake side. We figured that this would save the more expensive fine filter, and we could replace the cheaper course filter more frequently. It seemed to work for us, based on how much easier it got to breath in the room, but a quick google will show you a variety of configurations and designs from DIY air purifiers across the world.
One quick note, we are not scientists, and haven’t actually tested the particulate count in our houses after trying these things out. But the guy above in a lab coat is a scientist, or at least the University of Michigan says so. Also, anecdotally, our friends and families agree that these quickie filters really did do the trick.
Checking Local Air Quality
The Mendocino County Air Quality Management District shows hourly reports of particulate matter and ozone concentrations on their website. Look at the sidebar to the right, or scroll down if you are using a mobile device to the section titled “Air Quality for Mendocino.” The air quality is color coded from green (best) to purple (hazardous). You can also sign up for daily air quality email alerts from the Mendo Air Board at this link. The local air quality sensors are located at the Willits Police Department, the Ukiah library, and in Fort Bragg. Regular updates are also issued from the agency’s Twitter account.
The local air quality map is generated from the federal Environmental Protection Agency air quality monitoring site “AirNow,”and you can also still see an interactive map of air quality sensors, where you can type in a location to see the current air quality. Air quality, surface smoke, and ozone reports are also available from the National Weather Service’s air quality monitoring webpage.
Checked in with my brother who’s an actual climate scientist with a PhD who works on air quality and smoke propagation modeling for the west coast — he endorses the home-made fan filter idea, said it;s proven to work perfectly well. He noted that it’s probably more effective to put filter one the intake side of the fan though, for whatever reason the flat fan blades do a better job of making suction than fighting back pressure.
Also notable, I’ve been buying Nordic Pure filters on Amazon that are a lot cheaper than the 3M filters in the big box stores but highly rated (NYT Wirecutter, etc.) . You can also get higher MERV ratings (like a 14 or 15 which do a better job on PM2.5) and different thicknesses (thicker filter has more media area so air flows better). One example:
Hope that’s helpful to somebody.