As wildfires rage across Washington, Oregon and Northern California, residents may have to deal with smoke and ash for weeks or even months. Air scrubbers that contain HEPA filters and additional activated vapor-lock activated charcoal filters can not only purify the air of pollutants, but the smell of smoke as well. Smoke contains harmful particulates that can adversely affect health, especially for vulnerable populations such as children, the elderly, and people with asthma or cardiovascular disease. For these populations purchasing or renting an air scrubber may be a good investment.

Although both air purifiers and air scrubbers can help clean the air, they work differently and require different amounts of maintenance. Air purifiers work within the device itself, delivering clean, fresh air to your space immediately after installation. On the downside, an air purifiers require regular maintenance to replace the high-efficiency MERV filters which are quite costly. By comparison, an air scrubber does not have any components that will require regular replacement or maintenance, making it less expensive to run.

Maintenance of an air scrubber should be minimal. Most HEPA filters are designed to run continuously for a year, though many manufacturers recommend checking them every six months. Quality air scrubbers will have a series of filters; primary, secondary and the main HEPA (with an optional charcoal filter). It is much less expensive to replace the primary and secondary filters to ensure the longevity of the more expensive HEPA filter. The air scrubber has a key advantage in the fact that negative ions in the air will also attach to particles on surfaces in your home like countertops, doorknobs, and light switches. An air purifier can only clean particles that are airborne. If you are seeking both clean air and clean surfaces, an air scrubber is the way to go.

Air scrubbers capture small particles in the air, trap them in a dense mat of fine fibers within a filter and then blow out clean air. In order to be HEPA certified, air filters have to remove 99.97 percent of particles that are exactly 0.3 microns in diameter — a size that’s especially difficult to filter mechanically. Wildfire smoke particles are in the 0.4 to 0.7 micron range, according to the E.P.A. HEPA filters remove both larger and smaller particles, as well.

For homes in smoke-prone areas, including those near wildfire-affected areas, running an air scrubber should keep the amount of smoke in your home to a minimum. Beyond purifying your air, there are additional precautions to take if you live in a smoke-adjacent area or you’re concerned about pollutants. Keep your windows closed, and avoid spending too much time outdoors to keep from bringing particulates into your home. Do not exercise outdoors until the air quality is considered safe and if you must venture outside, clean your clothes and sheets to remove smoke after entering your home.

When choosing an air scrubber, ensure that the unit is HEPA certified; it’ll usually be listed as “true HEPA.” You’ll also want a model with a tight seal around the filter. Insist that the HEPA filter itself be certified to HEPA standards, with a certification label affixed to the frame of the HEPA filter.

Cubic Feet Per Minute (CFM) is one of the most difficult aspects of air scrubbers to compare between various pieces of equipment. First, peak (maximum) airflow ratings do not necessarily provide an accurate indicator of performance under “real life” operating conditions. Second, manufacturers often use vastly different ways to measure airflow, which often produce different results. Some claims are based on tests without filters in place; some simply quote blower curve ratings; others simply seem to use “guesstimates”. This makes it very difficult for a purchaser to compare different equipment on an “apples to apples” basis. Because of these discrepancies, it is probably not a good idea to put too much emphasis on differences in manufacturers’ published CFM ratings. However, quality units focused on commercial use will have accurate CFM ratings, typically exceeding the minimum value needed to clean the air in a residence.

Smoke can travel hundreds of miles from the source, so even if you live far away from the fire and are in no immediate danger, you could still have harmful smoke coming into your house. Usig a high quality air scrubber with multiple filters can help you keep your indoor air clean.