The Best Air Purifier for Smoke
Smoke consists of
- solid and liquid particles and
The exact chemical makeup of the smoke – i.e. the type/nature of particle and/or gas - depends on
- the “fuel” being burned
- the “conditions of combustion” – e.g. the chemical makeup of the surrounding air, the temperature at which the combustion is taking place, the presence of wind, etc.
I. Tobacco/Cigarette Smoke
One type of “fuel” for smoke is tobacco (tobacco accounts for 65 to 100% of the weight of a typical cigarette). The resulting smoke is composed of more than 5,000 chemicals.
Gaseous components include
- nitrogen (N2)
- oxygen (O2)
- carbon dioxide (CO2)
- carbon monoxide (CO)
- hydrogen cyanide (HCN)
- many others
Particulate components include
- carboxylic acids
- paraffin waxes
- many others
Note that certain chemicals are not limited to only one particular phase (gas or particulate). For example, nicotine might appear as both a gas and a particle (solid/liquid) in a particular sample of tobacco smoke.
Gaseous components of smoke can, for the most part, at least theoretically, be ventilated fairly easily. We will talk about these gaseous components later.
For now, we want to focus on the particulate components. These solid/liquid components CANNOT be as easily ventilated, making them of special concern.
Let’s take a closer look at the exact nature of these particles to better understand how to remove them from the air:
To do so, let’s categorize our analysis into
- primary smoke inhaled by the smoker
- secondary smoke inhaled by passive smokers (second-hand smoke)
Primary smoke produces approximately 70% of particles in the <0.3 μm range and about 30% of particles in the 0.3 to 2 μm range. Median particle diameter is 0.21 to 0.29 μm.
Secondary smoke produces about 95% of particles in the <0.3 μm range and only about 5% of particles in the 0.3 to 2 μm range. Median particle diameter is 0.08 to 0.11 μm.
For both, particle distribution in the >2 μm range is close to 0.
Similar findings here.
Obviously, we don’t need to be concerned about primary smoke. This smoke is directly inhaled by the smoker. However, secondary smoke might be a problem for you.
And this type of smoke has a median particle diameter around 0.09 μm.
A HEPA filter effectively removes 99.97% of particles 0.3 microns or larger. The smoke particles we’re most concerned about here are much smaller – 0.09 microns. Does this mean that HEPA is ineffective filtering these smaller particles?
Absolutely not. The efficiency rating is given in terms of 0.3 microns because particles of this size are the most difficult to filter. Smaller particles – that is to say particles smaller than 0.3 microns are actually easier to filter than particles in the 0.3 micron range. So rest assured that a HEPA filter will be very effective in removing airborne tobacco smoke particles from the air.
The Winix 5500-2 is our current recommendation for the best HEPA equipped air purifier on the market.
II. Wildfire Smoke
Recall that the chemical makeup of smoke is heavily influenced by the “fuel” that is burned. It’s not surprising then that the chemical makeup of wildfire smoke is subject to high variance because of the wide variety of “fuels” (different types of wood and vegetation) burned to produce it. This is the primary difference between wildfire smoke and cigarette smoke. For the former, the fuel varies. For the latter, the primary fuel is almost always tobacco.
Wildfire smoke is similar to tobacco smoke in that the chemical makeup of the smoke also consists of chemicals in both or either the gaseous and/or solid/liquid (particulate) state.
Many of the same gaseous chemicals in tobacco smoke can be found in wildfire smoke. Namely,
- Carbon monoxide
Of all these gaseous chemicals, only carbon monoxide is deemed a “pollutant of concern” by the EPA.
And you should never rely on an air purifier to remove carbon monoxide from your home. Make sure you have several carbon monoxide detectors installed and if any one of them starts beeping eliminate the source and ventilate. If the high CO levels are caused by wildfire smoke, you’ll likely need to evacuate as ventilating will only introduce more pollutants. Don’t wait around for your air purifier to take care of the problem!
The rest of the gaseous chemicals on the list, many of which are VOCs, appear in much lower concentrations than particles (more on these below) and carbon monoxide. For this reason, the EPA does not deem these gases pollutants of sufficient concern to warn the public to remove them.
The EPA calls particulate matter (PM) “the principal pollutant of concern” in wildfire smoke. PM in wood smoke has a size range around 0.4 to 0.7 micrometers – much larger than the particles that make up second-hand tobacco smoke. As we discussed earlier, the exact nature of these particles is heavily dependent on the nature of the “fuel” being burned. Namely the varying amounts of cellulose, lignin, oils, fats, resins, etc. in the wood and vegetation being burned.
Regardless of their exact nature these particles are still particles and they still have a particular size – mostly 0.4 to 0.7 microns. At this size a HEPA filter is still highly effective.
Our recommendation for a HEPA equipped air purifier is, broadly speaking, a 250 CFM unit – a unit that can process 250 cubic feet of air per minute. These units provide the best combination of processing power, energy efficiency, noise output, and value of all the different types of air purifiers on the market.
As for a specific model recommendation? We would again recommend the Winix 5500-2. This specific 250 CFM unit is our recommendation as the best air purifier for smoke, no matter if its tobacco smoke or wildfire smoke.
The Winix 5500-2 is going to do a great job filtering both the gaseous components (more on this in just a bit) – with its carbon filter - but especially the solid/liquid components of both cigarette and wildfire smoke – with its HEPA filter.
Filtering out the gaseous components of smoke
Earlier we mentioned that
- gases ventilate easily and that
- the EPA considers CO to be the only gas you need to be concerned about in wildfire smoke.
BUT that is not to say that other gases aren’t present at all or that those gases absolutely cannot have a negative impact on your health. You may also not be able to ventilate the gas components that are there.
The good news is that most air purifiers on the market are equipped with an additional filter (on top of a HEPA filter) for the sole purpose of gas filtration. That of course is the unit’s carbon filter.
We do want to note here that some carbon filters are better than others.
Specifically, pellet-based carbon filters are better than carbon filters that consist of a fibrous medium that’s only coated with carbon. If you’re interested as to how and why this is true, see our guide for activated carbon filters.
In any case, the particular model we recommend for particle filtration, the Winix 5500-2, is also especially well equipped for gas filtration. It’s equipped with a pellet-based carbon filter which, as we just discussed, is the superior type between the two types of carbon filters commonly found in air purifiers.
Extra Steps to ensure you’re breathing in clean air – especially if you find yourself affected by wildfire smoke
If you’ve been affected by wildfire smoke air quality is a serious concern. We believe that the concern is great enough that you need to take extra steps to ensure that you’re breathing in sufficiently clean air.
First, we would recommend that you purchase a particle meter. The meter will show you exactly how high the particle concentration is in your home. A HEPA equipped air purifier will be able to lower particle concentration in your home, but by how much? Is one unit sufficient? Do you need more? A particle meter will help you answer these questions.
run on turbo
If you live in an area affected by wildfire smoke you absolutely need to run your air purifier on its maximum setting to ensure that you’re removing particles from the air as quickly as possible.
Running a single air purifier on its maximum settings will ensure maximum particle removal rate for that particular air purifier but in order to remove particles even faster you need to strongly consider purchasing multiple units.
One top rated 250 CFM unit like the Winix 5500-2 can only service a room with a maximum area of about 300 sq. ft. For larger areas we recommend multiple units.
If your air quality is especially poor (eg. wildfire smoke is constantly coming into your home) then you absolutely need to consider multiple such units for the same area. Again, a particle meter is the only way to tell the full story here. With a particle meter in hand you’ll be able to tell for sure if you need multiple units or not.
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