Helping Kids Protect Themselves From Dirty Air, One DIY Filter at a Time

When the smoke clouds from the 2017 Northern California fires engulfed the Bay Area, Lil Milagro Henriquez found herself wrestling with one question:

“What can we teach young people about how to prepare for both our current reality, which is forest fires, as well as the escalating level of climate-related disasters that are guaranteed to come?”

Her answer: founding the educational nonprofit Mycelium Youth Network.

The organization’s goal is to prepare Bay Area youth for the challenges they face on a warming planet, providing them with the tools they need to cope with climate change.

While Mycelium works with all youth, Henriquez says, it prioritizes serving young people on the front lines. “Largely youth of color that are coming from low-income communities that are already under-resourced, already going through difficult environmental issues like water pollution or air pollution,” she said.

Just as the coronavirus pandemic and subsequent sputtering economy have thrown deep societal inequities into stark relief, it’s clear that a disparity exists around resources to mitigate the effects of climate change and air pollution.

As smoke once again blankets the Bay Area due to wildfires, those with wealth and connections may be able to flee to vacation homes, shelter with relatives, or outfit their homes with multiple air purifiers.

Henriquez’s work targets people without those options. Mycelium Youth Network educators work in a handful of Oakland and San Francisco schools, teaching classes on confronting the climate crisis.

One of the courses is “Clean Air is a Right,” in which students receive instruction on how to make their own air purifiers out of a new box fan, a furnace/HVAC filter and tape.

These materials cost around $50; that’s less than you’d pay for commercial air purifiers, which can cost up to hundreds of dollars.

But are these homemade purifiers effective?

“It works,” said Jose-Luis Jimenez, a professor of chemistry at the University of Colorado Boulder. He said the makeshift devices are “not rocket science,” and he’s been looking into how Do-It-Yourself purifiers can help filter air from both COVID-19 and wildfires.

He points to a peer-reviewed study out of Singapore, which found similar DIY air filters removing around 75% of particulate matter.

The purifiers in that study pulled air from outside, something doctors and scientists recommend avoiding when thick wildfire smoke infiltrates indoors. Instead, they say, it’s better to keep the windows closed and to focus on cleaning the air that’s already in your home.

It’s also more effective to clean the air in a limited area, says Theresa Pistochini, engineering manager at the UC Davis Energy Efficiency Institute and Western Cooling Efficiency Center.

“You want a smaller, enclosed space,” she said. “Like a bedroom that you’re trying to drop the smoke levels in. I mean, when it was really bad, a couple of us were sleeping in one room that we could manage to filter better,” she said, referring to her experience during the 2018 Camp Fire.

Jimenez and Pistochini both said that if you do make and use a DIY air purifier, there are a few things to keep in mind.

1. Use a MERV 12 or 13 filter. “It matters what filters you use,” Jimenez said. While HEPA filters are the strongest, their thickness may cause the box fan to overheat or fail. On the other hand, you don’t want anything too flimsy, Jimenez says. “The MERV 13 is like a sweet spot in between. That’s a pretty good filter. But it doesn’t make that fan work so hard.” Placing the filter on the back of the fan reduces the filtration a little, but experts who have tested it say placing the filter on the front of the fan can tax the motor more.
2. Don’t leave the DIY purifier unattended. Jimenez  and Pistochini both warn it could be a fire hazard if the fan gets too hot. Holmes, a make of box fans, says “Any other use not recommended by the manufacturer may cause fire, electric shock, or injury to persons.”
3. Place the DIY purifier in the middle of the room. You’ll want to keep it at a height midway between the floor and the ceiling, according to Jimenez.
4. Don’t expect the DIY purifier to last too long:  They’re meant as a short-term solution, for a few months or so. “You can use the filter until it’s visibly obstructed with smoke/dirt and then replace [it],”  Pistochini said.
5. Consult a doctor if you have lung or breathing challenges that may require more protection than what the DIY air purifier can provide.

Does having to create makeshift air purifiers sound a little bleak? Maybe. But Lil Milagro Henriquez of Mycelium Youth Network has a different perspective.

“The more that we can do now, knowing what is coming, the better young people could actually be prepared,” she said. “They can then take that information and that knowledge and do what young people do best, which is be creative, be visionary, be innovative.”