NYC air quality got you down? Here's how to make a homemade air cleaner.

June 8, 2023, 3:23 p.m.

It's relatively easy and safe to make a DIY air filter. Unfortunately, it may now come in handy more often.

A photo of a box fan, which can be used to make a homemade air filter.

As the skies over the New York City metropolitan area exude doomsday vibes, residents are looking for ways to make the air a little more breathable.

Some have returned to masking outdoors while others are wondering how to keep safe indoors amid the arrival of haze and an array of physical discomforts caused by wildfires burning in Canada. Reports of scattered shortages on air filters and AC units have begun to surface as the week of bad air quality continues, but there are relatively easy ways to rig your own air-cleaning machine.

While there is limited scientific information on the efficacy of DIY air cleaners in comparison to commercial air purifiers, early results from the Environmental Protection Agency and others suggest homemade air cleaners can reduce exposure to smoke particles.

Here’s how to create a homemade air cleaner, according to a guide from the EPA:

What you’ll need (All of these materials should be available at your local hardware store, big box store or online):

  • A 20x20 air filter, with a suggested rating of MERV 13
  • A UL or ETL safety-marked 20x20 box fan that is a 2012 model or newer
  • Choose one: duct tape, clamps or bungee cords

Steps

  1. Secure the air filter to the back of the box fan with your securer of choice: duct tape, clamps or bungee cords.
  2. Check the filter to make sure the air is flowing toward the front of the fan. A label illustrating the direction of air flow should be on the side of the filter.

Safety tips

  • Make sure you’re using a newer fan. The EPA recommends only using models from at least 2012. Prior to that time, fans were not tested in the same manner newer fans are, and could pose a fire risk. To be clear, the EPA does not recommend using older fans for DIY air cleaners at all, but warns that if you do decide to use an air cleaner powered by an old fan, you should never fall asleep while doing so.
  • Use fans that meet the UL 507 safety standard. Those will have a UL or ETL safety marking.
  • Follow the box fan manufacturer’s safety instructions, which may include avoiding extension cords.
  • Make sure your home’s smoke detectors are working.
  • Keep extra filters handy (most come in multipacks), since they get dirty more quickly during and at the end of a smoke event. Replace them when they begin to look dirty or smell like smoke.
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