In a Nutshell:

  • The particulate matter in wildfire smoke comes with real health consequences, and some populations are more susceptible than others (such as children, elderly, those with pre-existing conditions).
  • When it comes to wildfire smoke, any air filter is better than no air filter.
  • That being said, if you are going to invest in an air purifier, it’s worth purchasing one that can actually filter the particulate matter from wildfire smoke. Not all air purifiers are created equal, and not all air purifiers can adequately filter toxic wildfire smoke from the air in your home.
  • Ideally, you’ll want to get an air purifier that has an UltraHEPA filter and an adequate amount of activated carbon.

Suffocating smoke from Canadian wildfires filled East Coast skies in June 2023 and caught millions unprepared. Maybe you were one of the people who realized firsthand that the climate crisis knows no borders. 

With hundreds of uncontrolled fires still raging and many more predicted to start on the West Coast of the United States later this summer, it’s only a matter of time before poor air quality returns to places thousands of miles away from the flames. Now is the time to prepare with the best air purifier for wildfire smoke.

In this article, you’ll discover the key features of an air purifier responsible for eliminating the tiniest of smoke particles and gaseous contaminants from indoor air. Not all air purifier brands have these key features. Or, they may contain inferior components that aren’t as effective in cleaning your airspace.

Although any air filter is definitely better than no air filter, if you are going to invest in the best air purifier for wildfire smoke (as well as other kinds of air pollutants), you might as well know what to look for so that you can get the most out of your investment.

Whether you have an existing respiratory condition or wish to prevent the onset of one, clean indoor air is now a medical necessity. The best air purifiers for wildfire smoke described here will go a long way toward meeting that need for you.

RELATED: Check out this guide for more tips on how to take care of yourself and your loved ones during wildfire season.

This article contains affiliate links, which means we may earn commission if you decide to make a purchase.

Health Effects of Wildfire Smoke

The health effects from wildfire smoke (WS) exposure are many and widespread, even at levels far below the national standards. The primary culprit is particulate matter (particle pollution), PM2.5. This type of pollution is 2.5 microns or smaller in diameter. Ultra-fine particles (PM0.1) are only 0.1 micron wide, but extremely hazardous to your health when inhaled.

Adverse effects from PM2.5 exposure observed in numerous short-term studies conducted all over the world include:

  • Cardiopulmonary disorders (asthma, COPD)
  • Lung and heart impairments (reduced lung function, arrhythmias)
  • Premature death
  • Diabetes
  • Abnormal birth outcomes

A first-of-its-kind, recent long-term study (11 years) on over 490,000 people in the UK indicates higher rates of tumor incidence and of all-cause, nonaccidental mortality in people exposed to only a 10 micrograms/m3 of PM2.5 pollution increase in the last 1-5 years of their lives. 

By comparison, the air in New York City on June 8th, 2023 from Canadian wildfires was 460 micrograms/m3.

What Are the Pollutants in Wildfire Smoke? 

Wildfire smoke (WS) contains several different pollutants. The major ones are:

  • Particulate matter (PM2.5)
  • Ultra-fine particles (PM0.1
  • Carbon dioxide (CO2)
  • Carbon monoxide (CO)
  • Volatile organic compounds (VOCs)
  • Nitrogen oxides (NOx)

Let’s talk briefly about each of those.

Particulate Matter PM0.1 and PM2.5

Particulate matter (PM2.5) is the largest component of wildfire smoke. The United States Environmental Protection Agency (US EPA) sets standards on acceptable levels of PM2.5 as well as five other air pollutants that all states must adhere to. However, they consider only the size—not the source—of the particle pollution when determining how bad it is for human health. 

Ultra-fine particle pollution, however, is not regulated in the US at all.

Particle pollution PM0.1 and PM2.5, are the most insidious of all air pollutants. According to researchers, they enter the smallest alveoli in the lungs where they may remain permanently lodged unless they pass to the bloodstream. From there, they enter all body systems. 

Other smaller pollutants, such as polycyclic aromatic hydrocarbons (PAHs), can latch onto particulate pollution and likewise enter the body where they wreak havoc. Cellular stress, genetic damage, and inflammatory responses can result. 

Scientists have recently discovered that particulate matter in wildfire smoke is worse than that from other sources. 

Research published in 2021 assessing California wildfire smoke effects spanning a 14-year period in more than 1.6 million people admitted to hospitals for respiratory conditions shows that WS particulate pollution is associated with up to 10 times more adverse health outcomes than particle pollution from other sources. 

Carbon Monoxide (CO)

Carbon monoxide does not travel far from burning trees because it quickly reacts with other airborne contaminants. So, it’s not a major problem for people distant from wildfires. However, people living three miles or less from a fire, as well as firefighters, can be exposed to WS carbon monoxide. CO can be a health concern for them.

Carbon Dioxide (CO2)

Carbon dioxide is a product of combustion reactions. It’s a greenhouse gas that contributes to global heating. A small amount of carbon dioxide (0.04%) is naturally present in the atmosphere. 

As you’re probably already aware, however, the huge amounts of CO2 released from power plants, vehicles, and deforestation fuel the climate and ecological crises. 

Volatile Organic Chemicals (VOCs)

Some of the VOCs that are emitted from wildfires are known carcinogens. They are extremely small gaseous substances that pass right through high efficiency particulate air (HEPA) filters. Common examples of VOCs in WS that are known or suspected carcinogens are:

  • Acetaldehyde 
  • Acrolein 
  • Formaldehyde 
  • Benzene

Nitrous Oxides (NOx)

Nitrous oxides are released from wildfires as well. Urban areas can also contain high levels of nitrous oxides from car exhaust. In the chemical reactions that occur in the presence of nitrous oxides, ground level ozone (O3) forms. Both NOx and O3 are regulated by the US EPA under the Clean Air Act. 

Can Air Purifiers Trap Wildfire Smoke?

Certain air purifiers can do an adequate job of removing wildfire smoke (WS) from indoor air. But you need to be sure your air purifier contains two essential features: a HEPA filter and an adequate amount of activated charcoal. Most companies market their products as good for removing WS by considering only one of them.

1. How to Choose the Right HEPA Filter to Filtering Wildfire Smoke

A high efficiency particulate air (HEPA) filter will trap 99.97% of particles that are 0.3 micron or larger. Some smoke particles are this large so they will be removed from your indoor air by devices with a HEPA filter. 

However, there are many other WS particles that are much smaller than this. To give you an idea of how small smoke particles can be compared to other contaminants, look at the graph below.

Source: Sparks & Chase (2016)

Although wildfire smoke is not shown, tobacco and oil smoke are. Notice the size ranges for these: 

Tobacco smoke: 0.05 – 0.5 micron

Oil smoke: 0.01 – 1 micron

How does the size of wildfire smoke particles compare?

A 2019 study analyzing smoke particle size from a pine wood fire revealed a peak at 0.1 micron or less in the early stages. Later on during the course of the fire, larger particles were produced up to 1 micron in diameter. The majority stayed small, however, averaging only 0.2 micron. Notably, there was a high number of even tinier particulates, 0.02 micron wide, observed throughout the stages of the fire.

In other words, the majority of wildfire smoke particles are significantly smaller than what a HEPA filter will trap! 

So, to rid your home of wildfire smoke, look for an air purifier with an UltraHEPA filter that traps 95% of particles as small as 0.003 micron. That’s 100 times more effective than the large majority of air purifiers equipped with HEPA filters.

2. Looking for the Right Amount of Activated Carbon

Remember the carcinogenic volatile organic chemicals (VOCs) that are present in wildfire smoke? Look at where they fall on the graph of particle sizes above: 0.0001 – 0.001 micron. 

No HEPA filter—even UltraHEPA—will remove them from your indoor air.

To catch these super-tiny gaseous chemicals you need activated carbon. But just like there are different grades of HEPA filters, there are different grades of activated carbon. Unsurprisingly, they are not equally effective in removing WS smoke from the air.

What Is Activated Carbon?

Typically composed of coal or coconut husks that has been heated at over 1,000℉ under a vacuum so it won’t burn, activated carbon (AC) possesses an enormous surface area of highly porous material. This means there are plenty of nooks and crannies for extremely small chemicals like formaldehyde to attach to. 

An activated carbon filter removes VOCs from the air via adsorption (physisorption), a physical process of attachment between substances. The strength of the attachment depends on: 

  • The carbon source 
  • Granule size
  • How tightly the carbon atoms are packed 

Here is a short video that illustrates how adsorption by activated carbon works.

Which Type of Activated Carbon is Best to Trap Wildfire Smoke? 

The best type of activated carbon (AC) to remove wildfire smoke (WS) is a very fine mesh of AC beads or granules made of coconut shell

There are more micropores in AC from coconut shells than in AC made from other carbon sources. As the smallest of all pores, they can best trap super-tiny gaseous chemicals like formaldehyde.

A slow air flow rate through the air purifier set on a low setting maximizes the ability of a fine mesh AC to catch smoke particles. As air moves slowly over the AC, there’s plenty of time for extended contact between the VOCs and the AC. This results in better capture by the AC. 

Generally, ultra-small contaminants slip through on the first pass while larger particles get trapped. They may become attached in subsequent trips as air circulates continuously from your home through the device. 

Can an Activated Carbon Filter Release Wildfire Smoke Back into My Home?

Unfortunately, it is possible that an activated carbon (AC) filter can release contaminants back into your home. The reason for this is that adsorption, as a physical process, is reversible. So, desorptionthe inverse processmay occur. 

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) states on page 9 of its handbook chapter on gaseous contaminants: “Adsorption decreases as contaminant load on the adsorbent surface increases. Very low concentrations in the gas flow also result in low adsorption rates or even reemission of collected contaminants.” 

In other words, for maximum effectiveness and to prevent desorption, change your activated carbon filters or cartridges as often as is recommended. 

If your household possesses high levels of WS smoke, changing the AC filter or cartridge regularly is necessary. Follow the user manual instructions. 

You can gauge how much WS smoke is in your indoor air by testing for particulate matter with a high-quality portable air quality monitor. If readings are consistently high, you may wish to upgrade the type of air purifier you have. You can also check the air quality in your local area using a website like Purple Air.

Unfortunately, as ASHRAE indicates in the quote above, if too few VOCs are present in the air, they may not even be picked up by an AC filter. Worse, a low concentration of VOCs in your air could cause the desorption of VOCs from the filter back into your home airspace! This happens since chemicals naturally move from a place where they are more concentrated to a location where they are not as common if they are not tightly attached to the activated carbon.

To avoid this situation, choose an AC filter that has been chemically treated so air contaminants will bond tightly to it as described below. 

Chemisorption

In chemisorption, activated carbon (AC) is impregnated (saturated) with certain substances that capture small air contaminants such as formaldehyde by chemically bonding to it. When there is a strong bond, it cannot easily desorb (disengage) from an AC filter and reenter your home’s air. 

Potassium permanganate (KMnO4) is one example of a chemical used to make impregnated AC filters. It could also be applied to a non-reactive surface in the AC filter, such as an alumina pellet.

5 Tips to Keep Wildfire Smoke Out of Your Home

Air pollution is a silent killer. So here are some steps you can take to minimize your risk.

  1. When outdoor air quality is poor, stay inside with windows and doors closed. 
  2. Place wet towels or rags under exterior doors to prevent infiltration.
  3. Wet mop the floors and walls daily if air quality is poor.
  4. Vacuum all surfaces with a HEPA filter-equipped vacuum cleaner.
  5. Run air conditioning on recirculation mode if you’re sure it’s not bringing in outside air. Check the user manual to be sure. 

10 Tips: Home Air Purifier Use for Wildfire Smoke Removal

Note: The tips below on activated carbon are based on what activated carbon experts say.

  1. Use an air purifier possessing a pre-filter that will trap some contaminants so they won’t fill up the activated carbon as they move through the air purifier.
  2. Remove and vacuum the pre-filter daily with a HEPA-equipped vacuum cleaner. Replace before running the device.
  3. Buy a machine equipped with an UltraHEPA air filter.
  4. Purchase an air purifier with more than one pound of activated carbon (AC). The more activated carbon in the filter, the better the adsorption result.
  5. High air flow rate through an air purifier results in lower adsorption quality and shorter life of the filter. Its efficiency is then proportionately lower. So, do not use a high setting.
  6. Choose an air purifier with AC made from coconut husks. Bituminous coal is good, but it’s a non-renewable fossil fuel.
  7. If your air quality monitor indicates high levels of particulate matter or you still smell smoke after long periods of use, reduce the airflow even more.
  8. Since filter efficiency increases with decreasing the temperature, run an air conditioner to keep it cool.
  9. Because filter efficiency increases with decreasing the humidity, use a dehumidifier to keep the indoor moisture level at the US EPA-recommended 30-50% level.
  10. If you have a respiratory condition, are older, pregnant, or have young children, you may wish to invest in two air purifiers to eliminate the most pollutants possible: one with an UltraHEPA filter (for particulate matter) and a second with several pounds of impregnated AC (for VOCs and very small smoke particles).

Best Air Purifiers for Wildfire Smoke

Based on what we know about HEPA filters and activated carbon (AC), here are our recommendations for the best air purifiers for wildfire smoke. 

Unfortunately, a device that has both an UltraHEPA filter and several pounds of impregnated AC is not currently on the market to the best of our knowledge. So, if you’re really intent on eliminating the most wildfire smoke as technically possible, purchase two: an air purifier to eliminate most smoke particles via an ultraHEPA filter, and another with plenty of impregnated AC to trap VOCs. 

That said, it can obviously be quite expensive to purchase two different air purifiers. Remember that any air filter is better than no air filter, so just make the best decision you can based on your needs, budget, etc.

AirDoctor AD3000

best purifier for wildfire smoke AirDoctor

Price: $349 (with our discount). Financing is available.

The AirDoctor website states it uses an ultraHEPA filter. Nothing else appears about its activated carbon (AC) filter on the website or in the user manual. 

We called the company and spoke with Ruben who told us that the AD3000 contains 1.5 pounds of coconut shell AC impregnated with KMNO4. For the price, overall, this is a good choice. 

NOTE: This device comes with an air ionizer which produces a small amount of ozone. Ionizers do not remove contaminants from the air, but only make them fall to the ground. We recommend that if you purchase this device, set the ionizer to the off position.

[A note from Abbie: I have been using one of the AirDoctor 3500 for a couple of years now and I really like it. It’s easy to move around the house if I need to. It’s got an “Automatic” setting, which increases the filtering speed/strength based on the amount of pollution detected in the air, but you can also manually speed it up or slow it down. A light tells you when to replace the filters, and they are easy to swap out.

Also, another reason why I like the AirDoctor is because it’s one of the most affordable high-quality air purifier brands on the market.]

You can save $300 on your purchase when you use this link.


IQAir GC Multigas

best purifiers for wildfire smoke IQAir

Price: Starting at $1,369. Financing is available.

Equipped with a HyperHEPA filter with a 99.5% efficiency down to 0.003 micron, the IQAir GC Multigas is an excellent air purifier. It has 12 pounds of bituminous coal with potassium permanganate-coated alumina pellets. 

On the phone, Eric of IQAir told us that the alumina pellets serve as the surface on which chemisorption happens with VOC pollutants, while the AC surfaces are open to trapping other contaminants via physisorption.

This is obviously a more expensive option, but you’re getting more powerful purifier.


Airpura V700

best purifiers for wildfire smoke Airpura

Price: Starting at 849.98 (on sale)

Designed specifically to eliminate wildfire smoke, the V700 comes with a standard HEPA filter (down to 0.3 micron). It boasts 18 pounds of coconut shell AC enhanced with potassium iodide for chemisorption. 

You may upgrade it to a similarly weighted AC filter with potassium permanganate as the impregnated substance. Airpura also offers an ULPA filter with an efficiency down to 0.1 micron. Neither of these upgrades will significantly improve the device’s performance.

Airpura also offers the C600DLX which contains a whopping 26 pounds of AC, but the HEPA filter is only rated at 1 micron.


What About Austin Air?

Austin Air makes the Healthmate Plus air purifier. I contacted the company for more details on its components. Here’s their response:

“The Healthmate Plus contains…approximately 15 lbs. of coconut shell-based carbon (90%) and zeolite (10%) and is impregnated with potassium iodide.”

This means there is 13.5 lbs of activated carbon of the best type for adsorption of airborne pollutants. That is a substantial amount for a home air purifier!

Zeolite is a common adsorption medium in air purifiers, but unfortunately, it’s not very effective. Many sources call it an inexpensive filler added to give shoppers the impression that multiple media ensure greater contaminant capture.

The Healthmate Plus activated carbon is impregnated with potassium iodide which equips it for chemisorption of pollutants. 

Chemisorption involves the formation of a chemical bond which results in stronger capture of airborne pollutants. However, the contaminants could be released under certain circumstances as described earlier.

Zeolite, as a desiccant, quickly binds with moisture. This feature would reduce zeolite’s effectiveness to trap volatile organic chemicals.

This device’s HEPA filter is standard down to 0.3 micron. You can find more effective HEPA filters on other purifiers we recommend above.

Final Thoughts on the Best Air Purifier for Wildfire Smoke

In a climate emergency, no one can take clean air for granted anymore. When the outdoor air quality is so poor, it becomes essential to have a safe haven inside your home where the air is cleaner. It is a matter of life or death. 

Unfortunately, as long as fossil fuels are burned for energy, the risk of wildfires intensifies. As a result, it becomes more likely that you will encounter poor air quality more frequently.

An air purifier equipped to remove even the smallest of smoke particles is a major way to improve indoor air quality. The key component in the best air purifier for wildfire smoke is activated carbon made of coconut shells impregnated with a chemisorption enhancer. The more your device has, the better it will eliminate even the smallest of smoke particles from your home’s airspace.

AirDoctor, Airpura, and IQAir have the best air purifiers on the market for wildfire smoke removal. Invest in your good health with one or more of these air purifiers before the next smoke clouds move in.



About Jeanne

Jeanne Yacoubou, MS is an experienced researcher and writer passionate about all things environmental. She's written extensively on renewable energy, sustainability, the environmental impacts of diet, and toxic chemicals in food, water, air, and consumer products. When she’s not tending her organic garden or hanging out with her three teens, Jeanne is blogging about the latest scientific reports on our climate crisis. Jeanne holds master’s degrees in chemistry, ethics, and education. In between her graduate work, Jeanne served as a high school science teacher in Benin, West Africa as a Peace Corps volunteer for over three years.


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