Don’t Buy the Wrong Air Purifier for Wildfire Smoke

Wildfires have always been a part of life in some locations, but they are certainly becoming more severe and more frequent.

If you live in a wildfire-prone area, I’d definitely recommend getting an air purifier now if you don’t have one already. But even folks who don’t live in an area with regular fires can still experience the downstream effects of poor air quality as the smoke drifts to other places.

To help you find the best air filter for you and your family, I’m going to tell you the key features to look for in an air filter that can filter out 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.

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

This guide contains product recommendations, and we may earn a small commission if you decide to make a purchase. As always, we only make recommendations that are genuine.

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My Picks for the Best Air Purifiers for Wildfire Smoke

Based on what we know about HEPA filters and activated carbon (AC), here are my recommendations for the best air purifiers for wildfire smoke, listed in order from most affordable to most expensive.

(And again: 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.)

Below my recommendations, you’ll find a deep dive into what exactly to look for in a high-quality air filter and the health effects of wildfire smoke.

AirDoctor (3500 model and above)

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

AirDoctor uses an ultraHEPA filter which removes particles as small as .003 microns, which is great.

Nothing else appears on their website about its activated carbon (AC) filter on the website or in the user manual. So, I called the company and spoke with Ruben who told me that the AD3500 contains 1.5 pounds of coconut shell AC impregnated with KMNO₄. For the price, overall, this is a good choice. 

Any of the larger air purifiers from AirDoctor (the 5500) would also be a good choice. If possible, I wouldn’t recommend going with one that’s smaller than the 3500 because those don’t have an adequate amount of carbon.

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. I recommend that if you purchase this device, set the ionizer to the off position.

Abbie’s Review: I have been using one of the AirDoctor 3500 for a few 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. (I usually keep it on low so that the air can spend more time being filtered.) 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. Ideally, it would have more carbon, but with the ultraHEPA and at this price point, I think it’s the best bang for your buck.

Last thing I will say is that I live in Ohio. We did experience very poor air quality last year due to the Canadian wildfires, but if I lived in a place where the wildfires were closer, then I might consider investing in an additional carbon filter.

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

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Jaspr

Price: $1099 (before our discount!)

The founder of Jaspr actually worked in wildfire and flood restoration before starting his air filter company, so he’s seen the damage wildfires can cause.

HEPA has a 3-in-1 filter, which includes a:

• a pre-filter, which captures larger molecules and increases longevity of the HEPA+
• a HEPA+ filter, which can capture particles as small as 0.035 microns
• 1 lb of carbon

Jaspr has a sleek and easy-to-use design, too. And one of the main things that sets it apart from the AirDoctor is the fact that it’s low-plastic. The main outer part of the filter is made of stainless steel. Also, if you sign up for their recurring subscription for filter replacements, you get a lifetime warranty for the whole device, which is like unheard of anymore.

Use the code THEFILTERY for a minimum of 10% off. (Sometimes they increase that to 25% off during wildfire season, so be sure to check!)

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Airpura V700

Price: Starting at $1099

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.

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IQAir GC Multigas

Price: Starting at $1,399. 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 me 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.

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Health Effects of Wildfire Smoke

The health effects from wildfire smoke exposure are many and widespread, even at levels far below the national standards.

The primary culprit is particulate matter (particle pollution), aka PM_2.5. This type of pollution is 2.5 microns or smaller in diameter. Ultra-fine particles (PM_0.1) are only 0.1 micron wide, but extremely hazardous to your health when inhaled. They can penetrate deep into the lungs and even enter the bloodstream.

Adverse effects from PM_2.5 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)
• Diabetes
• Abnormal birth outcomes
• Premature death

A first-of-its-kind, recent long-term study (11 years) on over 490,000 people in the UK indicated higher rates of tumor incidence and of all-cause, non-accidental mortality in people exposed to only a 10 micrograms/m³ of PM_2.5 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. 😳

As you can see, wildfire is nothing to laugh at when it comes to potential health effects.

What Are the Specific Pollutants in Wildfire Smoke? 

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

• Particulate matter (PM_2.5)
• Ultra-fine particles (PM_0.1) 
• Carbon dioxide (CO₂)
• Carbon monoxide (CO)
• Volatile organic compounds (VOCs)
• Nitrogen oxides (NO_x)

Let’s talk briefly about each of those.

Particulate Matter: PM_0.1 and PM_2.5

Particulate matter (PM_2.5) is the largest component of wildfire smoke.

The US EPA sets standards on acceptable levels of PM_2.5 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 PM_0.1 and PM_2.5, 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 wildfire smoke 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 wildfire smoke carbon monoxide, which can definitely 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. Ideally, we don’t want to be putting even more CO₂ into the atmosphere via wildfires.

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. (This is why you want an air filter that has a HEPA filter and carbon.)

Common examples of VOCs in wildfire smoke that are known or suspected carcinogens are:

• Acetaldehyde 
• Acrolein 
• Formaldehyde 
• Benzene

Nitrous Oxides (NO_x)

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 NO_x and O₃ are regulated by the US EPA under the Clean Air Act. 

How Air Purifiers Trap Wildfire Smoke

Now we’re going to get a little more science-y. (You can skip this part if you want to! The air purifiers listed above have already been vetted for you based on the info below.)

Certain air purifiers can do an adequate job of removing wildfire smoke from indoor air. But you need to be sure your air purifier contains two essential features:

• a pre-filter (this traps larger molecules and extends the life of the HEPA)
• a HEPA filter
• and an adequate amount of activated charcoal

1. How to choose the right HEPA filter for 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 wildfire smoke 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.

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?

Well, 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 or HyperHEPA filter, which can capture smaller particles.

2. Look for activated carbon too

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 wildfire smoke from the air.

What is activated carbon, anyway?

Typically composed of coal or coconut husks that have been heated at over 1,000℉ under a vacuum so it won’t burn, activated carbon 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 to remove wildfire smoke is a very fine mesh of activated carbon 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. 

But be careful… activated carbon can actually release wildfire smoke particles back into your home.

Unfortunately, it is possible that an activated carbon filter can release contaminants back into your home. The reason for this is that adsorption, as a physical process, is reversible. So, desorption—the inverse process—may 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 wildfire smoke, changing the AC filter or cartridge regularly is necessary. Follow the user manual instructions. 

If you want, you can gauge how much wildfire 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. 

This called 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.

8 More Tips For Wildfires

Here are some steps you can take to minimize your risk of both short & long-term health effects of air pollution during wildfires:

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. 
6. Remove and vacuum your air purifier’s pre-filter daily (during & right after a fire) with a HEPA-equipped vacuum cleaner. Replace before running the device.
7. 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.
8. Change your HVAC filters immediately following a wildfire and then again a few weeks later.

For even more recommendations for staying healthy during wildfire season (including detox tips and more), see this comprehensive guide.

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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.

An air purifier equipped to remove even the smallest of smoke particles is a major way to improve indoor air quality.

If you can, I recommend investing in your health with one or more of these air purifiers before the next smoke clouds move in.

If you want to learn more about other things you can do to improve your indoor air quality on a year-round basis, there’s actually an entire lesson all about indoor air quality inside the Low-Tox for Real Life Course!

And to stay updated on the latest toxin-related news, get access to exclusive content, and more, sign up for Filtered Fridays.