Will An Air Purifier Help With Secondhand Cigarette Smoke?


Secondhand cigarette smoke has a strong odor, not to mention the dangers it poses to health.

But can an air purifier remove secondhand cigarette smoke? Yes, it can, although you may find you’ll need to purchase an air purifier with a larger air flow capacity than advertised and may need specialized filters that can eliminate smaller particles.

So, let’s go into more detail to give you what works and what doesn’t.


What Is Secondhand Smoke?

Secondhand smoke is smoke that is generated AFTER something like an appliance or fireplace has been used or AFTER it has been exhaled by a smoker.

Smoking specifically can produce two types of secondhand smoke:

  • mainstream smoke – smoke exhaled directly from a smoker.
  • sidestream smoke – smoke coming from the objects used to smoke, like a cigarette tip or hookah. This type of smoke is much more dangerous.

It contains a mixture of 7,000 chemicals, 1% of which are thought to be potentially cancer-causing. There are also many chemicals in the mix that drastically increase the risk of heart or respiratory diseases.

Secondhand smoke is dangerous at any level, especially to children and the elderly. For that reason, no minimum or maximum exposure levels have been established.

Contrary to popular belief, secondhand smoke is no worse than smoking. They’re equally dangerous.

The CDC states that just using venting or sitting in another area doesn’t eliminate secondhand smoke. In other words, either the smoke must be eliminated, or the nonsmoker can’t reside in the same building with the same ventilation system.

Since you can’t exactly move away from your family or roommates, the solution then is to find a way to eliminate the smoke rather than allow it to circulate in a home.


Secondhand Vs. Thirdhand Smoke

Once introduced, secondhand smoke can linger inside a home. This is referred to as thirdhand smoke.

The good news is that the research shows that this lingering smoke alone isn’t dangerous enough to cause cancer, but can mix together with other cancer-causing particles and settle into dust on surfaces. There is no definitive research on how dangerous thirdhand smoke is as of now, although it’s widely considered less dangerous than secondhand smoke.

Since thirdhand smoke can stay in a home for a long time, future research must address whether it has the same health effects as secondhand smoke at longer exposure times.


What’s Inside Tobacco Smoke?

As mentioned, tobacco smoke particles contain thousands of chemicals.

It’s considered an aerosol, or small solid particles that are suspended in a liquid (water vapor in this case).

The list of ingredients is too long to write here, but here are just a few examples:

  • nicotine
    • Is addictive, increases blood pressure, and causes hardening of the arteries that leads to heart attacks.
  • carbon monoxide
    • Causes dizziness, nausea, headache, and can cause death even at low exposures. Read more here.
  • ammonia
    • Causes a burning sensation in the nose, throat, and respiratory tract. Can lead to respiratory failure.
  • arsenic
    • Leads to lung and bladder cancer.
  • cadmium
    • Causes flu-like symptoms at acute exposures. At long-term exposures, causes bone, kidney, and lung diseases.
  • formaldehyde
    • An eye, nose, and throat irritant. A carcinogen that can cause leukemia and other cancers.
  • hydrogen cyanide
    • A general irritant at low doses, but can affect the nervous system and cause death within minutes at poisoning levels.
  • acetone
    • Another general irritant with symptoms that are similar, although less severe, than hydrogen cyanide.
  • lead
    • Generally causes weakness at low levels, but can be dangerous at high levels. Small children and newborns are especially vulnerable to lead poisoning since it has major developmental effects.
  • NNN, NNK, and NAT
    • Compounds specifically found in tobacco; made from nicotine. They are considered carcinogenic.
  • chromium
    • Generally considered a respiratory and skin irritant.
  • benzene
    • A carcinogen that can lead to leukemia in serious cases, but being exposed to tobacco smoke and benzene can affect blood-related cells and tissues.
  • tar
    • Carcinogenic and damaging to the smoker, but when it comes to secondhand smoke, tar can be an irritant.
  • and may even contain some radioactive materials
    • This has to do with the soil that the ingredients are coming from. Some tests have found uranium in tobacco products.

Sadly, a cigarette on average contains 600 ingredients, and the ones omitted from this list are just as dire.


What To Look For In An Air Purifier

When it comes to indoor air quality and air purifiers, most tobacco smoke is grouped under the category of particulate matter, or PM. This category includes particles that are up to 2.5 micrometers (microns) in size. Generally speaking, most cigarette smoke will fall in the 0.1 to 1.0 micron size range.

But since it contains thousands of chemicals, some tobacco smoke particles can be larger as well.

And if you want to eliminate tobacco particles that have combined with dust to produce thirdhand smoke, then you’ll need to address particles in the 20 micron range in size as well. (For more information on particles and indoor air quality, read this post.)


The Types Of Air Purifiers And Which One Is The Best Choice?

Picking the right air purifier to eliminate tobacco smoke comes down to two things:

Particle size and air flow…

By now, you should know that in order to combat tobacco smoke, you need an air purifier that’s able to filter out particles that are 0.1 to 20 microns in size. You’ll also need an air purifier that’s powerful enough, and that’s measured by the air flow.

In fact, this test by the Wirecutter showed that over 99% of smoke can be cleared out in a room within an hour, as long as the airflow in the room is sufficient.

So, amid all these depressing health effects I shared with you, there is some great news after all!


Particle Size

Nowadays, air purifiers come with multiple air filters, each serving its own purpose. It’s best to look for air purifiers that have the following filter types and features:


HEPA Filters

HEPA (High Efficiency Particulate Air) are filters that remove 99.97% of air pollution particles. This assumes that the particles are 0.3 microns or larger.

If you need to eliminate tobacco smoke, avoid any product that uses language like “HEPA-like” or “near-HEPA.” While those filters claim that they can remove 99.0% of particles, they usually can only remove larger particles that are 2.0 microns in size.

In other words, they won’t help you with tobacco smoke.

In all honesty, even a real HEPA filter will only be able to remove some tobacco-related particles since it typically traps only those 0.3 microns in size, which bring me to…


Activated Carbon Filters

Once you’ve made sure the air purifier you plan on buying has a real HEPA filter, the next thing that’s an absolute must is an activated carbon filter.

Activated carbon is unique in that it has a complex porous structure that gives it a large surface area to trap as many small particles as possible. This is known as adsorption. However, if you want a filter that’s a real workhorse in a smoking home, then you’ll need one that has heavy carbon beads inside, not just a lightweight film.

Activated carbon filters remove the smallest particles in tobacco smoke and are most useful of the filters on this list to remove odors as well. This is the filter that will fill in the missing gap and trap those small particles that the HEPA filter can’t.



Ionizers are considered as third level of “filtering” so to speak. I recommend to stay away from most of them since they can generate ozone, but there are some healthy ionizers that don’t. Those generate negative ions that tend to be harmless.

I have had a Winix air purifier in my home for the past 2 years. It has something called PlasmaWave technology, which can safely remove odors without generating dangerous ions.

While my home is non-smoking, it does a great job clearing out the heavy cooking odors in our large living area in just a matter of 20 to 30 minutes, and it’s shown to have eliminated smoke from a clogged up fireplace quite a few times in our home. Plus, it’s virtually silent on its first three power settings.


Air Flow

Hopefully all this advice can help you, but it will be useless if you don’t understand how air flow is REALLY calculated when it comes to air purifiers. Air flow in simplified terms is just a measure of how often the air in a room can be pushed out, or cycled, in a given time period. Usually, this is 1 hour.

First, I hope that you’ll look at air purifiers that use a reputable air flow rating system. Don’t trust everything you see since these numbers can be manipulated to suit the manufacturer.

The one I personally prefer is the AHAM Verifide rating, which gives you something called a CADR rating. A CADR rating essentially tells you how many square feet an air purifier can be used for based on the type of pollutant you’re trying to eliminate.

Products that have been rated using this system will have an AHAM label that looks like something like this:


CADR Label Example for Air Purifier


How easy, right?!

Not so.

I hate to say it, but there are many caveats when it comes to air purifiers, so you’ll need to pay attention to a few things with the AHAM Verifide labels as well:

  • The square footage rating is really for a room with an 8-foot ceiling, so you’ll need to convert their recommendation in terms of volume and recalculate if your room has higher ceilings.
  • Pay attention to the unit. Honest companies measure CADR in ft³/min. If it says m³/h, you’ll need to do yet another conversion calculation.  For example, a CADR of 135 ft³/min is equivalent to a 230 m³/h CADR.

If you need more information on how air flow and the CADR rating works, you can read this more detailed post.


Other Solutions That Also Help

I won’t give you the obvious solutions you already know, like opening windows and creating a designated, closed-off smoking area.

As a conclusion to this post, I’ll leave you with one final idea you may consider besides an air purifier:


A Highly MERV-Rated A/C Filter

Most homes use cheap filters that are there to just protect the A/C furnace from being damaged and aren’t intended to filter any small impurities.

Why not go a step beyond that and use your home’s A/C to help you clean the air as well? MERV-rated air filters are a great solution. A MERV-13 rated filter is hospital-grade and will do wonders to clean the air, but it may also restrict air flow in an average residential home.

So, the best compromise is the MERV-11 air filter, like this one on Amazon. Its a bit less restrictive to air flow, but is still very much capable of removing smoke particles. And, it’s a great choice if you have pets as well.