The Best Particulate Matter Air Purifiers & Testing Your Exposure Levels

Finally, my message is getting brighter.

In my first two blog posts on particulate matter I treated the topic of what particulate matter is and, the topic of the 10 most devastating health effects of particulate matter

This blog post, however, considers the topic of lowering your particulate matter exposure and testing for levels in your environment. Even though the topic seems really simple, in reality, it's really intricate.

In fact, this blog post is almost 8,000 words long. I'll tell you all what you have to look for in an air purifier, how to test particulate matter levels with several meters and by reading maps about your environment, and give you the recommended air filters within different categories, such as budget, mid-range, and premium!


Here we go...

And, if you don't know what particulate matter is or why it matters for your health, read part 1 and part 2 of this blog post series.  


Testing Air Quality For Particulate Matter Levels

Observe on that map that particulate matter concentrations also vary widely across the globe.[145Less densely populated areas in Western Europe are generally very safe. East and South Asia and sub-Saharan Africa are generally very much polluted.

Consider the following problem:

Most of the data that's collected on particulate matter concentrations are actually not coming from your house, the building you're working, or the train or road you are spending time at every morning.

The data on that map is often sourced from 5 or 10 blocks away from your home. Most people thus don't have any actual data on the PM2.5 or PM10 pollution at the locations they're spending most of their time.


Mapping Paticulate Matter Levels

Data on how polluted your location is are in fact very important.

Let me explain:

Let's say I'm living in Paris.

In that case, there might be tens of different particulate matter measurement systems placed around and outside the city that all yield different outcomes.

That sounds great, right?

Just observe what the measurement system three blocks away tells you, and you know how polluted your street is, right?



Particulate Matter Levels In Different Cities

There's sometimes a 10-fold particular matter difference between different places. 

Don't believe me?

View the map of Paris below:

air quality index meter Paris outcome

(again, you can observe the current air pollution levels around your location on this map.)

There's even a big difference between several places in the inner city.

Air pollution maps can only give you a very general impression of the particulate matter you're exposed to.

If you really want to know how much air pollution you're "ingesting" on a daily basis, you can thus not rely on the government's data--you have to take your own measurements instead.

And, no, I'm not selectively showing you cities to prove my point.

Here's the data on Mexico city on October 16th, 2018 (this blog was re-published on this website from an earlier blog!):

air quality index meter mexico city

Again, more than a 10-fold difference in air pollution levels...

New York City?

An even bigger discrepancy:

picture displaying how polluted new york city is

Observe the 25-fold difference in exposure there. Of course, there are anomalies to that 10-fold difference observation.

Beijing is one example:

air pollution levels in beijing

Unfortunately, it also seems that there's nowhere to hide in Beijing--but that's another topic I'll get back to later.

Please observe that not all places in the city are measured in terms of air quality.

If you want real-time data on how you are doing in your house, office, during transit, or when you're spending time in the park, you thus need to measure air pollution levels yourself.

The seasons also affect how much particulate matter hangs around in the air. Rain does the same thing. 

The air quality map can give me a totally different outcome tomorrow compared to what it's telling me today. If a factory shuts down tomorrow, I may be exposed to 70% less particulate matter compared to today.

Circumstances thus matter...


Why You Need To Actually Test Your Air Pollutant Exposure Levels

Bottom line: if you're worried about air pollution - and specifically particulate matter - in your environment then you cannot exclusively rely on maps.

(Neither can you rely on the government's solutions.)

One common government recommendation is to tell people not to go outside when air pollution levels are too strong. To me that's a very imperfect solution because you're no longer able to expose your eyes and skin to sunlight - which I consider a prerequisite for optimal health.

The solution is more complicated - stay with me to find out why in section seven...

Another important point:


Where You Live Matters

Local sources of particulate matter pollution are generally more damaging than what you'd get exposed to from far away.[29]

Remember I told you that some of particulate matter pollution could originate from a desert? While you may get exposed to some particulate matter from far away, most is actually sourced from your direct environment.

Of course, even though smaller types of particulate matter such as PM2.5 and PM0.1 can travel farther, but particulate matter from nearby busy streets, heavy industry, and airports are most killing...

airports are devastating for overall particulate matter levels
Airports can double particulate matter concentrations for miles

If you "cannot move" due to air pollution because you're stuck to a given city (due to your job for example), think again.

Remember that air pollution levels can vary 10-fold across different areas in the same city.

Moving out of the city center towards the periphery can thus have a dramatic impact on the particular matter you're exposed to on a daily basis.

(And, often the city center might be cleaner because there are no highways nearby and car traffic might be limited.)

Living very close to a busy road, for example, dangerously increases your overall mortality risk.[140That statement does not just reflect my opinion--it's a solid fact.


The Most Important Particulate Matter Exposure Sources

So let's consider a few case studies of exactly where particulate matter originates from.

Consider the deaths that are attributable to just PM2.5 in China in 2016:[207]

  • Industrial coal for industrial processes: 155,000
  • Transportation: 137,000
  • The residential burning of biomass: 136,000
  • Non-coal industry: 95,000
  • Coal for energy generation: 87,000
  • Intentionally-created outdoor fires: 70,000
  • Residential coal burning in homes: 41,000

That's 721,000 people who've lost their lives due to just PM2.5 in a single year in China. China's neighboring country, India, counted 666,000 deaths from PM2.5 that year.


Significance Of These Statistics

What should these statistics teach you?

Traffic is not the only particulate matter source that should worry you:

If your neighbors are burning wood or coal to generate energy, and the smoke is directed your way very frequently, then you're going to suffer the consequences.

If you're living next to a coal power plant, you may want to move to the other part of the town if possible, so that you can still keep your job in that same city.

But I'd like to go one step further:


Buying An Air Quality Detector

An "air quality detector" is a great tool to measure PM2.5 and PM10 levels in your direct environment:

Again, measuring your air quality is highly recommended if you live in a polluted area. You'll get real-time feedback on how good (or bad) the air quality at your location is. 

The air quality detector listed above costs $129, and measures both PM2.5 and PM10 (and additionally, formaldehyde and "VOCs" other air pollutants). CO2 levels are also measured by that monitor.


Budget Particulate Matter Detector

If you want a less expensive (and less all-around) model, consider this budget option for a particulate matter quality detector:This budget device only measures PM2.5, which is more important than PM10.

On another note:

Unfortunately, I've not seen any commercial grade affordable PM0.1 air quality detectors. 

The average person does not need to buy that meter either...

If you don't have an air purifier yet, then the main reason you'll want to measure the air quality is getting a general impression of the PM2.5 levels in the location you're spending time at (over time). 

(The topic of air purifiers is treated in the next section)

If you do have an air purifier, then dropping levels of PM2.5 with that air purifier will always be combined with even further lowering of PM0.1, as air purifiers capture the latter particles roughly equally well as the former.

It's also very rare to have extremely high PM2.5 particle levels while having very low PM0.1 levels--PM2.5 particles can thus act as a good benchmark for PM0.1.

(PM0.3-sized particles are the most difficult to capture for air purifiers, moreover, so both PM2.5 and PM0.1 are cleaned pretty effectively with a high-quality product.)


Understanding Priorities In Testing & Fixing

Bottom line: if you're living in the civilized world and the air quality map shows a trend of lower air quality in your environment, it's time to acquire more data on your location.

When measuring the PM2.5 and PM10 levels in the environment you're spending time daily, make sure to collect data over longer periods of time.

Of course, if you measure dangerous levels for several days, you'll already know what you need to know. In some instances, however, high PM2.5 might, for example, be harder to detect:

Your daily transit, for example, may only take an hour but expose you to 90% of the particulate matter that day. Neighbors burning wood next door may also only be detectable at certain times...

And if you do detect high levels of particulate matter in your home or office?

In that case, read the next section on using air purifiers...

Want to know what to do right now to decrease your risks?




Particulate Matter Air Filter & Purifier Guide: Budget & Mid-Range Options

In this section I'll cover the most important guidelines for using air purifiers to reduce particulate matter in your environment - I'll also give you the best product recommendations for both the budget and mid-range. 

(Premium style options are covere in the next section!)

Keep in mind whether you need an air purifier really depends on your circumstances.

Not everyone needs an air purifier.

And you may also be thinking: "great, I've already decided to get a high-quality air purifier now, so how long will it take before my health improves?"


Why Air Filters & Air Purifiers Are A Game Changer

Finally, I can talk about the bright side of my message: health improvements due to lowering the amount of particulate matter you're exposed to happen almost immediately.

Of course, the damage that has been accumulating for decades cannot be undone in a few weeks or months.

Nonetheless, it's better to start cleaning the air today rather than tomorrow if you're exposed to lots of air pollution.

Blood pressure and stress hormone levels will drop off immediately after you start purifying your air, for example...


What Is An Air Purifier?

So let's begin with the basic questions: "what's an air purifier?"


Air purifiers are devices which filter the air that circulates through them. These devices contain two main components that are important to remember: 1) a motor; 2) a filter.

The motor in the air purifier makes sure that air moves through the filter. The filter then captures any harmful substances and prevents these substances from re-circulating through the air.

The dirty air thus enters the air purifier, and clean air exists the purifier - if all goes well...

Not all air purifiers are created equal though.

The more air moved through the filter by the motor, the higher your energy costs will be. More restrictive filters (i.e., the more particles trapped by the air purifier) will increase energy costs also.

You, therefore, don't want just any air purifier: you'll want a high-quality product:


What Are HEPA Filter?

Let me introduce you to "HEPA" filters - an abbreviation for "High-Efficiency Particulate Air" filter.

In general, HEPA filters are considered the golden standard for consumer air purifiers. HEPA filters basically entail that lots of particles are trapped by such a filter...

Next to regular HEPA filters, "true HEPA" filters also exist. "True HEPA" generally filter the air better than regular HEPA filters.

A true HEPA filter removes 99,97% of all particles bigger than 0.3 micrometers. Only 0.03% of particles bigger than 0.3 micrometers are thus re-emitted into the air.

In other words:

If 100.000 particles enter the filter, only 30 will come out "alive" and are re-introduced into the air.


What Particles Do HEPA Filters Remove?

Let's consider which types of particles are specifically removed by true HEPA filters.

In most cases, true HEPA filters are most effective with larger (PM10) and much smaller (PM0.1) particles, and least effective around the 0.3-micrometer particle-size range. In the least effective range, 99,97% of particles are thus still removed from the air.

You'll thus want a "true HEPA filter" instead of a HEPA filter, as the latter is not necessarily standardized to filter at maximum efficiency.

(Don't be fooled by advertisements that filters are "highly efficient" or "HEPA-like", as these air purifiers almost never live up to expectations and use deceptive marketing.)

Additionally, filtration "efficiency" is not the exclusively important parameter to look out for when buying an air purifier.




Why Quality Matters When Buying An Air Purifier

The air purifier you're buying needs to be effective.

If you've got a 300 square feet room and you place a true HEPA air purifier in that room which has a maximum capacity to filter 150 square feet, the filtration process is not going to be optimal.

Let me explain...

Remember the motor component of an air purifier?

Without a strong motor, an air purifier cannot move enough air around in a room, and cannot effectively clean that air.

Of course, true HEPA filters need to be functioning properly in order to work correctly. If your filter has defects, filtering will not be effective nor efficient.

Additionally, some companies claim that true HEPA filters cannot capture really small particles such as PM0.1.

To be honest, that's bogus.

Again, true HEPA filters do the worst in particle ranges of 0.3 micrometers. Both above and below the 0.3-micrometer size, true HEPA filters actually entrap more air pollutants such as PM2.5.


What Are True HEPA Filters?

Keep in mind that this blog post is specialized towards the topic of particulate matter, and I'm mostly recommending true HEPA filters to filter that substance.

Of course, (true) HEPA filters filter many other toxins from the air:

  • Dust, both heavy and settling
  • Soot, which results from incompletely burned carbon, often originating from wood, coal, or petroleum
  • Smog
  • Allergens
  • Pollen 
  • Viruses, bacteria, and mold


The Limits Of HEPA: What Substances Do HEPA Filters Not Filter Correctly?

Some substances are not filtered with a (true) HEPA filter, such as Volatile Organic Compounds (VOCs). Smoke from tobacco, oil, and wildfires (insofar they are not solid or liquid), and odors can generally not be removed by (true) HEPA filters.

The simple reason is that air purifiers are made to move air through them, and gases can thus also move through the filter.

For your air purifier to also stop gases, you thus need an additional filter to remove gases, such as an "activated carbon filter".

Fortunately, most modern air purifiers actually contain additional filters to remove gasses.

I'm just mentioning this fact so that you're not under the impression that just buying a true HEPA filter is always sufficient for all circumstances.

The problem with carbon filters is that they're of different quality. Not all carbon filters are great at filtering out most gases.

Again, you'll want a high-quality product...

Oh yeah, one more thing:


Correctly Using An Air Purifier

You have to keep in mind that air purifiers are not all-powerful (or "omnipotent").

If you're keeping your windows opened up in a polluted environment, no amount of air purifying is ever going to keep your environment clean.

If you've got 3 dogs and you're cooking indoor in a small 160-feet apartment, one high-quality purifier might not be enough either.

On the other hand:

If you're sleeping in your small bedroom in your house in the woods that's located in the middle of nowhere, an air purifier that cleans 1300 square feet is overkill - you'll waste your money.

The goal is thus to find the air purifier that's right for you... 


(Advanced explanation: the filters inside a HEPA purifier are often made of fiberglass or synthetic nonwoven fibers). The former demands an increased air pressure compared to the latter, and therefore filters more particles from the air. On the carbon filters for gases: some gases such as formaldehyde or methane cannot be properly filtered by carbon, and thus most modern air purifiers cannot capture all air pollutants.


My Recommendation

So, the million dollar question (or rather $100-800 question) is this: "what air purifier would you recommend?"

I'll tell you in a second...

Let me first consider a problem:

The problem in answering that aforementioned question is that I don't have a team of several people and a laboratory to test many of high-quality air purifiers for several days.

And yet, I can make a good air purifier recommendation to you?


By combining the data of several great air purifier tests that have been carried out in the last year - I've included these tests if and only if these tests have described their testing methodology well.

I've synthesized the data of the following air purifier reviews of the last years (2017-2018):

  •, who buy air purifiers themselves (and thus do not receive them as a gift), update their website daily, and test products in many different circumstances.
  •, which is part of the New York Times, is reader supported and has spent hundreds of hours comparing different air purifiers. Purification speed and the ability to deal with larger rooms was one of the key metrics included in their test.
  •, who put a very heavy emphasis on air purification (as opposed to energy efficiency or air purifier noise levels), and have tested 80+ different products.
  •, a dedicated website for reviewing air purification systems that has existed for years.
  •, another website dedicated to exclusively reviewing air purifiers.
  •, who've carried out independent lab tests with several air purifiers and also consulted with air quality experts.

(Again, this blog post was created before its publication in 2021 on the Alexfergus website)


Air Purifier Testing Methodology

From each independent test I extracted the following data:

The number 1 product choice was allocated 10 points, their number 2 choice got 9 points, their number 3 choice 8 points, and so forth. I also included the reasons for choosing the different products in the eventual product analysis.

Some tests did not contain 10 different products, but I've nevertheless included as many products were available. In other words, if only 4-5 products were displayed, I've allocated points to these 4-5 products.

My recommendations are based on adding up the point allocated to each individual air purifier.

The top-3 air purifiers have been listed below (with their final scores).

One remark:

All air purifiers in consideration have (true) HEPA filters, and are thus capable of filtering out particulate matter. Particulate matter is, of course, the reason you're reading this blog post in the first place.

So what's the outcome?

Here we go:

(This list was last updated on October 24th, 2018.)

Let's consider the top 3 products: 

Taking first place, the Coway AP-1512HH, which scores 40 points in total:

This air purifier can improve air quality in rooms up to 530 square feet (~50 square meters). 

This device costs $205 (USD) at this point in time and is available in black and white colors to match your interior design. The design is also somewhat smaller than the other two air purifiers coming in at the second and third place.

The Coway has one big advantage: both power consumption and filter replacement are relatively inexpensive - at a low ~$45. The AP-1512HH purifier is also paired with an "Energy Star-rating". 

Sure, $205 is a lot of money for some people, but it's your best bet for improving indoor air quality.

This air purifier packs quite the punch for a $200 product, with four filtering mechanism: 1) an easily cleanable pre-filter that removes larger particles such as dust; 2) an odor filter; 3) a true HEPA filter; 4) an ionizer (emitting negative ions into the air--dust or allergens are positively charged, which are purported to be offset these negative ions).

Ionization, however, may prove to be pseudo-scientific and is considered and its benefits are unproven at this point. Fortunately, the ionizer can be turned off, which also inhibits (possible) ozone being emitted from this air purifier.

Fortunately, the California Air Resources Board has specifically tested the ozone emission of this air purifier and was tested at 0.050 parts per million, which is very low.[254]

Another remarkable upside is that the Coway AP-1512HH keeps filtering the air quite well year-after-year, even though the efficiency of most air purifiers degrades over time.

The noise of this air purifier is low, but there's one clear downside: its LED lights shine bright, a topic I'll come back to later.

Overall, it's hard to overestimate how good of an air purifier this is for a $200 price. The Coway AP-1512HH easily outperforms many air purifier that are two or three times as expensive, while also costing less in terms of upkeep.

Coming in at second place is the Winix 5300 or 5500 at 36 points:

Different air purifier consumer reports used different versions of the Winix, but as these devices are almost the same, I've rated the Winix 5300 and 5500 as if they were the "same device".

(The Winix 5300 misses some options which the Winix 5500 does include.)

Rating these very similar devices separately would make them end up outside the top three, and studies only tested either of them.

So why the Winix 5500?

First of all, this air purifier can filter rooms up to 360 square feet (or 33 m2). The Winix also automatically tones down its filtering intensity when the air gets cleaner - saving energy that way.

Secondly, this air purifier contains a carbon filter in addition to a true HEPA filter, to remove odors from the air. Carbon filters need to be replaced every 6 months. 

Thirdly, a big upside about the Winix-5500 is that it only costs $145. The replacement filters are more expensive, however, than the number one air purifier - coming in at around $60. 

Over time, the Winix can thus become more expensive than the Coway AP-1512HH, even though you're paying less up front.

The LED lights on this Winix air purifier can be dimmed, which is the fourth plus. 

So why does the Winix take second place instead of first place? Some independent tests rate the filtrating rate of the Winix 5500 lower than the number one spot, the Coway AP-1512HH--although others disagree by grading them as having similar capacities. 

Compared to the Coway AP-1512HH, the filters of the Winix 5500 are very easy to replace. If you're totally "non-tech-savvy", then opt for the Winix instead of the Coway AP-1512HH. 

The pre-filter of both air purifiers need to be removed and cleaned every two weeks, so keep that fact in mind. 

(Pre-filters spare the main HEPA filter - which is more expensive to replace - and the inclusion of a pre-filter is thus economical.)

Taking third place is the Honeywell HPA300, with 27 points:

At the time of writing, this air purifier is priced just below $200 - but nevertheless filters an area of up to 465 square feet (43 square meters).

The Honeywell air purifier contains two different filters - the most important types - which are a carbon pre-filter for gases, and a true HEPA filter (for our much-hated particulate matter).

This air purifier is specifically built towards reducing allergens - that fact alone might place this device at your first place if you've got problems in that health domain.

Energy costs of this air purifier are low, and the device has an "Energy Star-rating."

One downside of this air purifier is its looks. 

New HEPA filters are also more expensive than the number one rated device above (averaging $60). Honeywell filters need to be replaced every 6 months with normal use.

A last upside: the air purifier is pretty quiet, making this air purifier ideal for a mid to large-size bedroom. 

The best low-budget option - when you only have like $100 to spend - is the Germguardian, with 26 points.

Keep in mind that this device is best used for smaller rooms - costing only $105.

This air purifier filters areas up to 200 square feet (18 square meters).

In addition to trapping particulate matter through the HEPA filter, odors are also captured and germs are killed through an "ultraviolet C" air sterilizer. Filters need to be replaced every 6-8 months.

The upside is that this smaller air purifier is less noisy than the air purifiers in the number one and two positions,  and is thus ideal for bedroom use. The downside for bedroom use, however, is that the LED lights are harder to dim.

Tip: another great location to place this air purifier is close to your desk if you're working in an office. A Germguardian can keep the air in your immediate vicinity clean.

Filter replacement costs $35, and the ultraviolet C air sterilizer costs 15 bucks to replace. One downside over the Coway AP-1512HH is that the Germguardian can become more expensive over a longer period of time due to replacement and electricity costs.


Air Purifiers For Bigger Rooms

Additionally, if you've got very big rooms, such as an office floor, I would not recommend the products I've listed above.

Instead, buy an air purifier that's specifically built towards cleaning much bigger rooms, such as the Alen Breathesmart or the Coway Airmega-400.

Both are great options and were rated very highly in the air purifier reviews I've synthesized. 

Alen BreatheSmart 75i

Coway Airmega 400

These two air purifiers that are targeted towards larger rooms have been tested to 1,300 to 1,500 square feet rooms, or 120 to 140 square meters. Even in such large rooms, they can filter the air every 30 minutes.

Of course, their pricing reflects this increased filtering capacity, ranging from $550 to $750. 

Let's review the upsides of the Alen BreatheSmart 75i first:

  • Lifetime guarantee
  • Energy efficient
  • The sound that's generated by this device is "pink noise", which actually helps you sleep
  • extremely quiet. If you're very sensitive to noise pollution, this air purifier will get more attractive for you
  • Available in an insane amount of customization colors to match our interior
  • Comes in two versions, either specialized towards smoke, cooking odor, and VOCs (from furniture, for example), or specialized towards allergies and dust instead. For combating particulate matter, the latter option is better.

How about the Coway Airmega 400?

  • Energy efficient
  • Available in black and white model
  • Less expensive than the Alen Breathesmart while also cleaning more air (1500 square ft).

Downside? You can control the Airmega 400S version with WiFi. Solution? Always buy the regular Airmega 400, not the S version. The regular Airmega does not have WiFi connectivity.

The "S" signifies smart, which is usually pretty dumb considering that the amount of wireless radiation is growing exponentially and at a very harmful rate.

Please remember that air purifiers that are targeted towards bigger rooms are also bigger themselves, and will be highly visible when you place them in a small living room.

Disclaimer: keep your body at a 6 feet (roughly 2 meter) distance from the air purifier to prevent excessively exposing yourself to electromagnetic fields. So no placing an air purifier directly next to your bed.

Remark: please don't buy an air purifier that's targeted towards office use for your small condo or your bedroom, as you're literally wasting your money by that course of action.

Moreover, bigger air purifiers don't just cost more money for your first purchase, but their energy demand and filter replacements are also more expensive.

The reason you're spending much more on their energy cost is that a more powerful motor is necessary for such an air purifier to clean an entire office floor.

One legitimate reason to buy a much more expensive air purifier is if you have lots of issues with your airways, such as asthma or extreme allergies.

Another reason to go for maximum air purification is if you've got heart, lung or brain disorder--in an earlier section, I've demonstrated that particulate matter contributes to and even causes such diseases.

If you've got lung issues, for example, a 90% instead of 70% reduction in particulate matter in your living room can make all the difference in the world - especially over time

Better be safe than sorry in such instances, and spend $750 to clean the air in your house...

Note: none of the air purifiers listed above emit serious amounts of ozone.[249; 250; 251; 252; 253; 254]

Ozone is an air pollutant in and of itself. You can get airway irritation and lung problems from ozone, directly countering the reason you're buying an air purifier in the first place.

Some previous generation air purifiers did in fact emit ozone. Air purifiers emitting ozone is thus sheer lunacy. 

(Nerds: please keep in mind that I'm not talking about ozone therapy here, which may or may not have merit--I've not looked at the evidence thoroughly there, and cannot judge.)

Keep in mind that your air purifier filters absolutely need to be replaced over time.

Not replacing filters is not an option...

Companies will often tell you how long a filter can last. There's a good reason a "shelf-life" is allocated to filters, as they can get stuffed over time so that less and less air is let through them.

If you fail to timely replace carbon filters that remove gases from the air, these toxic gases can even be re-released into your environment. 

Bottom line: follow the instructions for your product.

Air purification often times do not get the intended effects because people think their filters can last for two years, even though the company supplying the air purifier recommends replacement every 6 months.

One more thing:

One downside of many air purifiers is that they still contain LED lights that emit blue light.

Blue light will inhibit production of the "melatonin" hormone which aids your sleep quality. It's, therefore, best to put a piece of cloth over the display of the air purifier when you're not looking at the current status (e.g. the current pollution rate in the room). 

Another method of avoiding the blue light is to place the air purifier behind a closet, so that blue light is not projected at you.

Don't let your sleep quality be ruined because you're staring at blue light at night

Now, a very simple question remains: "should everyone buy an air purifier?"

The answer is a categorical "no".

Whether you would benefit from an air purifier depends on your personal context. Of course, if you're spending lots of time in one location where particulate matter levels are very high, then I would recommend an air purifier almost regardless of circumstances.

But if you've just got dust mites in your house, I would first recommend you'd change the carpeting and curtains.

If you're exposed to particulate matter in your car 12 hours a day, and only exposed to particulate matter in that situation, putting an air purifier in your home won't help either - that point should be self-evident.

In what circumstances would I recommend an air purifier?

Well, the most important instance is if you're 1) spending lots of time each week in the same location; 2) if that location has high particulate matter (or air pollution) levels.

You might also have seen portable air purifiers being sold online.

My opinion here:

I cannot recommend any portable air purifier almost regardless of circumstance with a clear conscience. 


Le'ts go through severla popular models:

With the hOmeLabs 3 in 1 Air Purifier with HEPA it's impossible to turn off blue light. The product is thus unusable in your bedroom at night. Remember that blue light after sunset disrupts your sleep.

The hOmeLabs may be usable during the daytime though, especially during transit. If you're spending lots of time in one location, I'd opt for one of the earlier static $100-$800 static models I've mentioned earlier. 

Another popular portable air purifier, the "Wynd", seems to necessitate an internet connection and thus relies on wireless radiation that you don't want to be putting out when you use a portable air purifier next to your bed or at your desk.

Thus: avoid the "Wynd"...

The next and last "portable" air purifier, the Levoit LV-H132, needs to be connected to the power grid and weighs almost 7 pounds. The upside of this air purifier is that doesn't emit electromagnetic radiator and that its light can be turned off.

Nevertheless, because the Levoit product is pretty heavy, it's hard to use as a portable air purifier.

Most of the smaller air purifiers are also not tested for ozone emissions, which is another red flagI'll only add a recommendation in this section once a product does not actively harm your health.

There's one last mater I need to consider in this section - which relates to a question many people actually have:


Studies Showing The Effectiveness Of Air Purifiers

"So how do you know for sure that (true) HEPA air purifiers are actually working?"[213; 214; 215; 227; 229; 247; 257; 261; 262; 263; 269]

Great question...

This is a question that actually pops up over and over again...

Short answer: because many scientific studies have actually investigated air purifiers and demonstrated they do work.

Insane claims can actually be found on the internet that HEPA filters don't actually improve your overall health--such stupid claims can be easily debunked. 

Let's look at some examples demonstrating that HEPA filters work by looking at several scientific studies:

  • When mothers used HEPA filters during pregnancy, babies who were born at term had higher birth weights. 

    Another group of pregnant women who used a portable HEPA filter ended up with lower toxins (cadmium) in their blood.

  • Allergies? 

    Allergens in the bed and on the floor are reduced with HEPA filtering. Cat allergen levels are also reduced by air purification, although symptoms of people with cat allergies did not significantly decrease.

    Nasal allergies do decrease in intensity by using HEPA filters though.

  • In the case of asthma, there is some conflict of evidence, especially regarding earlier studies. Newer studies do demonstrate that beneficial effects of HEPA filters for asthma exist.

  • Then there's the subject of particulate matter. 

    First example:

    When children with asthma got an air purifier in their home that reduced particulate matter, their symptoms improved. The group that received a placebo (and thus a non-working HEPA filter) experienced a worsening of their symptoms. 

    Unfortunately, this was a very small scale study.

    Indoor particulate matter levels were also reduced by 43%. While 43% might not sound perfect, the long-term effects of that 43% on your health can be dramatic. 

    And by the way: in the study, one HEPA filter was placed in a Cali home. I think with several HEPA filters in such homes you'd be able to get a 90% reduction or more - these homes are big...

    Second study example:

    Indoor particulate matter concentrations were reduced from an average of 49 to just 9 micrograms per mwith an air purifier - that's a five-fold reduction of particulate matter right there. 

    Third example:

    In an environment with 15 micrograms per m3, which is not high under international standards, high-efficiency filtration reduced particulate latter to 8 micrograms per m3 - thus halving the level.


    Systolic blood pressure - meaning the pressure in the vessels during the period in which the heart is beating - was reduced with 3 points.

    Fourth example: 

    Having a HEPA filter in your truck can reduce PM2.5 concentrations by 37%, even though new particulate matter is continually added back to the truck because drivers are continually on the road.

    Fifth: staying indoor and running a HEPA filter can even reduce indoor toxins (as long as the windows are closed) when forest fires are raging.

    Enough examples...

Overall, 80-90% of studies show positive effects of HEPA filters. Newer studies are generally more positive towards HEPA filters - because of technology improvements.

Concluding that modern HEPA filters don't work is like concluding that condoms don't function today because anti-conception was so bad in the 19th century...

Don't make that (logical) mistake...

The bottom line is that HEPA filters do work for purifying the air, and specifically for reducing particulate matter.

50-90% reductions of PM2.5 are not uncommon.


Health Effects Demonstrated In Particulate Matter Studies

Now, are the health effects of using HEPA filters indoor enormous?

Unfortunately, there are not that many studies that investigate the lowering of particulate matter by using HEPA filters while also measuring direct disease outcomes (such as whether participants have a stroke or heart attack).

There's indirect proof though - if you want to be certain that lowering particulate matter helps.

What proof?

Large-scale studies that tracked the decline in particulate matter levels in the Western world after governments began legislating actually demonstrate that lower PM10 levels lead to better health.[311; 312; 313]

Let me give you some examples:

  • Less PM10 in the air caused lung function to decline less rapidly with aging.
  • In Switzerland, reducing outdoor PM10 concentrations in the 1990s led to less bronchitis, coughing at night, colds, and eye irritation in children. Sneezing and asthma intensities were not reduced though.
  • In Swiss adults in roughly the same period, (chronic) coughing, wheezing, and breathlessness were reduced. 
  • If you were living in the US in the 90s, a reduction of PM10 also caused a reduction in overall mortality.

To my knowledge, no large-scale studies of PM2.5 have been conducted because PM2.5's effects have not been measured for such a long period of time. 

The bottom line is this:

If reducing outdoor air PM10 pollution by 10-20% already increases your health, then 50-80% reductions of PM2.5 and PM0.1 will certainly help your health.

Clean mountain air: indispensable.


Air Purifiers And Noise Pollution

There's one downside about air purifiers I should inform you about: noise pollution.

(If you'd like to know more about noise pollution read my extensive guide about that topic.)

The sound levels emitted by air purifiers can amount to somewhat more than 50 decibels.

To give you a frame of reference:

50 decibels has the loudness levels of a regular conversation, of background music, a dishwasher, or very light traffic outside your house.

(If you're further removed from the air purifier, the loudness will become less intense of course.)

The problem with 50 decibels?

When you're exposed to that 50 decibel sound level during the nighttime its already considered noise - 40 decibels is considered the safe limit by the European Union for nighttime exposure levels.

Even that European Union research is not as strict as it should be though.


Just 30-40 decibels can negatively affect sleep quality.

For that reason, I'm a big fan of the Alen BreatheSmart 75i as a high-end option - even if you don't have a huge apartment.

Only buy that BreatheSmart if you've got money to spare and think the lowered noise outweighs the decrease in sleep quality. On the lower settings, the Breathesmart remains under the 30-decibel threshold for optimizing sleep quality.

Remember the Breathesmart filters up to 1300 square feet. As an alternative, the same company also offers:

Avoiding excessive noise is always best for your health.


Why You Need To Monitor Particulate matter Levels

Lastly, the best way to make sure your house or office is low in particulate matter is to combine an air purifier with measurement.

If particulate matter levels go down, you can simply conclude that your health will improve over time. 

That's it...

Everything you need to know about using air purifiers to reduce particulate matter. The next step is to look at other strategies you can use to lower particulate matter in your environment.


Advanced explanation: keep in mind that the studies I cite above do not just treat the topic of particulate matter, but are also based on other types of air pollution such as pet allergens or pollen. The main claim, that HEPA filters specifically and air purification in general work, stands. 

There are also good explanations why HEPA filters do not demonstrate enormous health benefits (yet). I'll give four reasons. The first reason is that long-term studies inquiring into the health benefits of HEPA filters are rare. Remember that air pollution damages health over time. Just a few days in a polluted city is not going to make you sick--a few years will damage you though. The second reason is that many studies show that participants don't always activate their air purifier when they ought to. One reason can be that study participants themselves don't believe air purification can really solve their problems, and thus even though the placebo group does not activate their sham air purifier either, HEPA filters' true effect size is always underestimated. The third reason is that participants don't always maintain their air purifiers correctly so that the positive health effects drop down considerably over time. Fourthly and lastly, air purification technology has developed over time, especially the last two decades--studies that were more negative in the year 2000 may be invalid as of today, as better air purifiers may show results where older models did not. Overall, the future will probably demonstrate that HEPA filters do have big health benefits


The Best Premium-Quality Air Purifier On The Market Right Now

I'm not going to type too much here to regurgitate an argument that Alex has already made in the past.

But, if you really want maximum protection in any particular room, then I recommend reading up on Alex's article EnviroKlenz Mobile Air Purifier System Review: How Does It Compare?

(You can buy the  'EnviroKlenz Mobile Air System' HERE.
Basically, if you really want the best filter out there right now, get this one. The unit does set you back to ~$700 for a 60-meter room, or about 600 square foot. So, this unit is more expensive than any of the previous options, but, well worth it in my opinion if you sleep or work in the same room every night and you're exposed to toxic air.

Again, chek Alex's perfect article and his experience after using this product for a few months here: EnviroKlenz Mobile Air Purifier System Review: How Does It Compare?


Finishing Thoughts: An Air Filter Alone Already Lowers Particulate Matter Exposure By 90-95%!

I hope you get it!

Afer my first two very depressing blogs about particulate matter, you now know you've got good options controlling your exposure levels to particulate matter.

The place that people tend to spend most time anyway, and the place that's commonly the most polluted - indoor environments - is also the place that you can most easily control.

of course, if you're working outdoor all the time, in a polluted place, then there's another issue. You can still control your exposure while you're at home, and that will certainly help, but if you're breathing in toxic air 24/7 in a big city, I would carefully consider my options.

Slowly losing your health over the course of years is perhaps not worth it... 


Items Mentioned:


This is a post by Bart Wolbers. Bart finished degrees in Physical Therapy (B), Philosophy (BA and MA), Philosophy of Science and Technology (MS - with distinction), and Clinical Health Science (MS), and is currently a health consultant at 


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