Do HEPA Air Purifiers Remove PM2.5? (Find Out Now)
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Do HEPA air purifiers remove PM2.5

Do HEPA Air Purifiers Remove PM2.5?

Do HEPA air purifiers remove PM2.5, you ask. Yes, they do. According to ScienceDirect, HEPA air purifiers can reduce PM2.5 by 29 percent in settings with very high concentrations. While 29% may not seem like much, it’s significant. And according to the EPA, True HEPA air purifiers actually remove particles smaller than 0.3 microns in diameter better than they do larger ones.

And a bunch of air quality experts working independently have carried out tests that have shown that HEPA air purifiers do a ton more than they receive credit for. As you’ll learn a little later, the experts in this post found that True HEPA air purifiers can filter down to 0.001 microns!

Now, before we proceed any further, might you be looking for an air purifier proven to remove PM2.5 effectively? My best recommendation remains the IQAir HealthPro Plus. It’s expensive (costs almost $1k as of this writing), but it works. It’s been shown to filter out pollutants in the 0.003-micron range. Take a look:


IQAIr HealthPro PLus (New Edition)

It pulls contaminated air from the bottom through its arched base and pushes it out sideways near the top. See the arrows above. 



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However, one shouldn’t rely on portable room air cleaners exclusively to push down PM2.5 levels. Air quality experts recommend that air purifiers be used alongside other effective measures. These measures include improving ventilation as well as addressing the source of indoor pollution.


Research on the Efficacy of True HEPA Air Purifiers


Here’s a list of studies, small and large, that provide important findings about PM2.5 and the ability of HEPA purifiers to eradicate them. Let’s hear what these authorities have to say about whether these devices actually take out PM2.5 from the air.


Experiment #1


The first “researcher” cobbled together a DIY air purifier and used an air quality monitor to test its efficacy. The particle counter used could test the machine’s effectiveness down to 0.5 microns. Note that the AQI in the room read “Very Unhealthy.” Also, 4 regular air purifiers were tested alongside the homemade contraption. These were Blue Air, Philips, IQ Air, and Cannon air purifiers.




After 1 hour, the reading had improved to somewhere between “Unhealthy” and “Good.” Another 1 hour after that, the number stood at “Moderate.” Between the 4th and 7th hours, the counter showed that the air quality was “Good.” You can view the findings via the link above.

For the 4 regular air purifiers, the results didn’t significantly deviate from the findings described above. In these tests, the air purifiers removed 80 to 90 percent of particles smaller than 0.5 microns!

The researcher leaned another astounding truth. Shockingly, they found that air purifiers are actually better at eliminating particles that are smaller than 0.3 microns. Our researcher reasoned that Brownian motion was probably responsible for that effect. Chandrasekhar (1943) defined Brownian motion as the stochastic motion that particles made after being randomly bombarded by molecules.


Experiment #2


While researching for this post, I discovered another “researcher” who’d performed a similar experiment. This person tested 10 air purifiers, and the particle counter used detected particle pollution down to 0.01 microns. The experiment took 10 minutes.



Interestingly, the air purifiers in question removed as many PM2.5 as they did PM10 particles!

These two findings are some of the best answers I’ve seen to the question: do HEPA air purifiers remove PM2.5? Admittedly, these tests aren’t exactly scientific research. I mean, the sample size is too small. But in my opinion, these results trump all the personal testimonies we hear or read about all the time.


And What Does the EPA Say?

When manufacturers of HEPA air purifiers describe their devices, they focus on their ability to remove 0.3-micron particles. You often hear statements like, “This air purifier captures 99.997% of particles 0.3 microns in diameter or larger.”

I’d heard and read that statement or its variants countless times. Now, one critical question popped into my mind. Are HEPA air purifiers any good when it comes to eliminating the smallest PM2.5 particles?

According to the U.S. Environmental Protection Agency, 0.3-micron pollutants are the “most penetrating particle size.” Small wonder makers of these air purifiers pay tons of attention to particulates in the 0.3-micron range.

The following statement by the EPA comforts me a lot. The EPA says that HEPA air purifiers handle particles smaller or larger than 0.3 microns with greater efficiency. In other words, these machines may remove more than 99.97% of particulates smaller or larger than 0.3 microns. That should be very good news for anyone with concerns about the quality of the air they’re breathing indoors.


New Research Reveals Shocking Findings


Do you know why the question above is VERY important? It’s because the smallest particles are way more dangerous than larger ones. They’re so small that they have no trouble inching their way into the most vital body organs.

A recent global scientific review suggested that PM2.5 particles are insanely more dangerous than previously thought. The work was published in the Journal CHEST, the official publication of the American College of Chest Physicians. According to this source, these teeny-weeny particulates may affect every cell in the human body. Now, that’s more than a chilling realization.

And a 2019 study found an association between short term exposure to PM2.5 and increased hospital admissions. You can access this study in one of the most respected medical journals worldwide, the BMJ.

Evidently, PM2.5 particles are extremely dangerous. That’s why everyone who loves their life should seriously consider using a True HEPA air purifier. As you can see, anyone can get affected. Not just asthma and allergy sufferers. Keep that in mind as you ponder whether investing in a product like this makes sense to you.

What Does PM2.5 Mean?


PM2.5 particles

Image source: The EPA


PM2.5 refers to particles whose diameter is equal to or smaller than 2.5 microns. Now, these particles are microscopic. You just can’t see them, unless you’re viewing them under a powerful electron microscope.

But how small is 2.5 microns? You can learn about particle sizes in this comprehensive guide to buying the best air purifier. In that guide, you’ll find a detailed chart that lists more than 10 common particles and their respective size.

Indoor air pollution particles are so small that expressing them in inches wouldn’t make much sense. A diameter of 1 micron is the same as 0.00004 inches. See, it’s hard to visualize 0.00004″. To help you understand this better, human hair is roughly 30 times thicker than a PM2.5 particle.


PM2.5 Vs PM10, What’s the Difference, Which is More Dangerous?


Both categories of particles are dangerous. However, PM2.5 is more lethal than PM10. That’s because these particles are much smaller and harder to detect. In addition, they’re way more difficult to remove or control. The human eye can detect particles as small as 10 microns. You should be able to see some PM10 particles.

Inhaling PM2.5 is extremely dangerous to your health. Mounting evidence finds that breathing these particles can lead to serious health-related issues. In fact, a recent comprehensive review of particle pollution linked it to a whole range of deadly diseases. Some of these diseases include diabetes, Parkinson’ disease, Alzheimer’s disease, heart disease, obesity, and asthma.

But what are PM10 particles? These are particles whose diameter stays in the 2.5–10 microns range. They’re relatively larger than PM2.5. Still, you won’t be able to see the vast majority of them without an electron microscope. PM10 are sometimes referred to as coarse particles and PM2.5 called fine particles.


Examples of PM2.5  and PM10 Particles


Combustion particles, viruses, tobacco smoke, fine metallic dust, and organic compounds are examples of PM2.5  particles. Household dust, pollen, and various types of mold, tobacco smoke, mold spores, dust mites, and lint are examples of PM10.

Why have I listed cigarette smoke particles as both PM2.5 and PM10? It’s because their size is a range rather than a single number. The size of tobacco smoke particles ranges from 0.01 to 4 microns.


What Causes PM2.5?


PM2.5 particles originate from many different sources. They’re mainly the result of combusting fossil fuels, organic materials, and other types of materials.

Power plants, automobiles, planes, wildfires, and burning organic matter during land preparation produce these particles. Volcanic eruptions and dust storms also contribute immensely to particle pollution.

Some of these particles are directly released into the atmosphere, such as during a dust storm or volcanic eruption. Or, when you’re installing a new countertop in your kitchen during a renovation.

Also, these particles get formed when particles and gases in the atmosphere react with one another. An example of this is when SO2 (sulfur dioxide) from sulfur-rich sources reacts with water droplets and oxygen. The resulting pollution is sulfuric acid, or acid rain.


What’s a Healthy PM2.5 Concentration?


First off, it’s best to track the 24-hour PM2.5 number as it provides more reliable info than a shorter duration. Concentration levels are critical, but the length of exposure determines a lot. A shorter-duration reading may not tell you everything you should know regarding whether you should take action.


Healthy PM2.5 Concentration Level


According to the EPA, a 24-hour PM2.5 reading of anywhere between 0 and 12 μg/m3 is ok. If that’s where your reading is, you don’t need to take any action. That level of exposure translates into “little to no risk.”


Moderate Level


If your 24-hour reading lies between 12.1 and 35.4 μg/m3, the EPA considers that to be moderate exposure. At that exposure level, sensitive people will likely experience a few respiratory symptoms. If that’s you, it’s time to start reducing your exposure.


Unhealthy for Sensitive People


Between 35.5 and 55.4 μg/m3, you’re looking at a level of exposure that’s unhealthy for sensitive people. Those with asthma or other respiratory challenges may experience more pronounced symptoms.

Also, elderly people with cardiopulmonary disease may see premature mortality. People grappling with heart or respiratory diseases, children, and the elderly should try reducing their exposure.


Unhealthy PM2.5  Concentration for Everyone


If your reading hovers between 55.5 and 150.4 μg/m3, that’s considered unhealthy for everyone. At this level, even healthy people may experience increased respiratory effects.

Everyone, not just children, the elderly, and those battling respiratory conditions, should do everything possible to minimize exposure.


Very Healthy


Next, any reading between 150.5 and 250.4 μg/m3 is deemed very unhealthy. Anyone exposed to this level of concentration might see their respiratory symptoms worsen significantly. Again, reducing prolonged exposure to these pollutants is the way to go.


Hazardous Levels


Finally, readings between 250.5 and 500.4 μg/m3 are said to have hit hazardous levels. At this exposure level, there might serious aggravation of respiratory disease. Also, elderly people living with cardiopulmonary disease may see a seriously increased premature mortality.

In addition, children and everyone else face a serious risk of respiratory effects. Children and elderly people living in areas with such particle pollution levels should stay indoors. Everyone else must stay away from outdoor exposure as much as possible.


What’s the Best Air Purifier for Removing PM2.5 ?


The best air purifier for tackling PM2.5  is one that uses a True HEPA filter. Amazon and other online retailers carry a wide variety of such devices.

But it’s advisable to read a couple air purifier reviews before committing your dollars. Here’s a detailed comparison of 3 Honeywell allergen removers to help you as you shop around.


I believe the IQAir HealthPro Plus is the best air purifier for PM2.5. This article contains a brief review of this great air purifier. And as mentioned earlier, the thing costs a pretty penny.


What’s a Normal AQI (Air Quality Index)?


According to the EPA, an Air Quality Index between 0 and 50 μg/m3 means “Good” air quality. 51 to 100 μg/m3 is moderate while 101 to 150 μg/m3 is unhealthy for sensitive people.

Next, readings between 151 and 200 μg/m3 shows that the pollution level is unhealthy for everyone. AQIs between 201 and 300 μg/m3 indicate that pollution has reached a very unhealthy level for everyone. Finally, readings between 301 and 500 μg/m3 say you’re dealing with a hazardous level of indoor air pollution.


Final Thoughts On Whether HEPA Air Purifiers Remove PM2.5


A few studies show that portable air purifiers help reduce PM2.5  pollution. But they may not remove 100% of these microscopic particles. While installing an air purifier in your rooms is advisable, it’s not enough to resolve particle pollution. People should incorporate air cleaning devices into a wider indoor air pollution reduction strategy.

You now know what PM2.5   and PM10 particles are and what harm they’re capable of causing. Now, it’s time to take steps to protect yourself against the adverse consequences of inhaling polluted indoor air.

Would you like to read a few air purifier reviews before you leave? Why not start with the best air purifiers without filters? Or check out these best air purifiers with washable filters?