Sadly, wildfires have become common for residents in states such as California and Oregon, prompting them to consider how best to deal with the smoke and ash that lingers afterwards for weeks or even months. Many residents have taken to air purifiers to help reduce the particulate pollution in their homes, and Tim Heffernan, a science writer and editor at Wirecutter, has offered some advice for those looking to purchase such a device.
At a minimum, Heffernan recommends HEPA certified air purifiers, which are rated to remove 99.97 percent of particles that are exactly 0.3 microns in diameter, though he also tested and found positive results with certified models that remove virtually all particles as small as 0.01 micron, one-thirtieth the HEPA standard.
“Most of us spend a lot of time indoors,” Mr. Heffernan said. “And indoor air is more polluted than outdoor air. It kind of comes down to what we have in our homes: pets, rugs, furniture that traps dust. And many homes are not terribly well ventilated.”
In addition to the HEPA certification–which Heffernan states should be listed as “true HEPA”–individuals seeking an air purifier will want to make sure the device has a tight seal around the filter to get the full effect of the device. Some models may list a CADR (Clean Air Delivery Rate) rating, which will indicate how efficiently the model will work depending on the size of the room it’s placed in. Heffernan suggests a CADR of at least 200, which means the unit effectively delivers the equivalent of 200 cubic feet of pure air per minute.
For a more cost-effective solution, it’s also possible to upgrade an existing HVAC system to improve air quality with filters that trap smaller particles. In these instances, filters with a MERV (Minimum Efficiency Reporting Value) rating between 7 and 13 are likely to be nearly as effective as “true HEPA” filters.
Within the air purifier market, buyers should watch out for dubious additional features, such as models that produce ozone to destroy pathogens (ozone is actually a respiratory system irritant) and ones that claim to reduce VOCS (volatile organic compounds), as very few models truly have such a capability.
Regardless of model, Heffernan recommends checking an air purifier every six months for buildup on the filter. Furthermore, for those in smoke-afflicted areas, Heffernan suggests keeping windows closed when possible, washing sheets and pillowcases, and when able mopping instead of vacuuming to avoid kicking up any dust or smoke that’s settled. Lastly, for those wishing to purchase a face mask, they should seek masks with an N95 or P100 rating, as these are the necessary levels to provide adequate protection from smoke particles.