Category Archives: Air Pollution Essentials

Air Pollution Essentials

Here is my collection of evidence-based articles regarding air pollution’s effects, as well as what you can do to decrease your risks.

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How To Choose An Air Purifier in China

Isn’t it a total hassle to buy an air purifier in China, especially for expats? Back in places like the USA, when we shop for anything we can luxuriously research using consumer magazines and other review sources, wisely shopping around online and in stores as educated consumers. Here, many of us struggle with Chinese so are at a loss on local shopping websites, forcing us to rely on word of mouth and a tiny handful of imported brand stores. This usually has meant that many of us end up buying the same legacy brands, usually quite reputable but also usually at incredibly marked up prices. Even if fluent in Chinese it’s still very difficult to research credible data. It’s a classic Economics 101 example of information asymmetry, where the typical consumer doesn’t have all the information that they need to properly research the marketplace, thus giving too much leverage to the seller — leading to a very unbalanced supply and demand curve where we pay much more than we should, for a machine that may not be exactly what we needed.

So in my continuing efforts to educate people about healthy living in China and elsewhere, I’ve written a basic how-to guide to buying an air purifier, similar to my pollution mask buyer’s guide. I won’t be discussing the need to buy one, as I’ve made it blindingly obvious in many other articles that an air purifier is essential for anyone living here, especially children.

Seal your windows and doors!

Pre-step: Hire An Independent Testing Company

I suggest that anyone with a villa, large home or a business should think about saving some time and possibly a lot of money first by hiring an environmental consultant to assess your site. You may think famous Brand X air purifier is great — but do you need one, two, three or more? And can you get equal benefits from a much cheaper model? And which speed setting do you need to use for general use? Let them figure out all the complicated cubic meters and assess how much machine(s) you need. They also do a great job looking for — and fixing — air leaks around windows and doors (which is cheap and effective advice for everyone, even in your one-window tiny dorm room). They also are experts on the brands of machines available. They should also come back for free for a specified time and double-check that all is OK. I’ve personally used two such companies, both run by expats: Environment Assured, which aim to get your indoor PM2.5 concentration under 10 ug/m3 (the WHO standard, and my goal at home), and also PureLiving China, whose indoor goals for PM2.5 follow the higher Chinese target of 35 ug/m3. I’m sure there are other companies out there, as this surely should be a booming industry. I personally think the evidence is overwhelming that your goal should be to keep your indoor PM2.5 under 10 ug/m3 all the time — even when the outside air is crazy bad. It can be done, and it doesn’t have to be as expensive as you fear.

Step 1: How much/many do you need? Let’s do some math

Kids' college funds, or air purifiers? Hm...
Kids’ college funds, or air purifiers? Hm…

If your needs are simple or small, or you’re only here a few months, you can definitely handle this on your own. First, in order to know how much or how many machines you need, you first need to do some math: you need to calculate your room’s volume. Most air purifier ads mention either recommended room size (适用面积) as square meters or airflow rate (风机空载风量), often written as CADR, and listed as cubic meters per hour. Here are the steps:

  • First, measure your room and get the area of your floor space, in square meters. For example, my dining room, living room and long hallway are collectively 84 square meters (“84 m2”).
  • You could be done already! Now you could just check the ads for the recommended room size (适用面积) and do the math. For example, I need 84 m2 of protection — a very large area. I don’t see any single machine rated that high but I see a few in the 40-70 m2 range. So in theory, two machines rated for 61 m2, with a combined area of 122 m2, should easily take care of my 84 m2.
  • That’s the easiest way — but I actually find it more accurate to use airflow and volume because it factors in the room height. A 20 m2 room with standard 2.6 meter high ceiling will need a lot less machine than the same floor space with cavernous 6 meter high ceilings, as many villa front rooms may need. So let’s do more math! Multiply your room area by the room height. For my front rooms: 84 m2 x 2.5m height = 210 cubic meters (210 m3) volume.
  • Since a proper air purifier needs to replace the entire room air at least five times an hour (5 Air Changes Per Hour, or ACH) to really be effective, you need air purifiers that collectively can cover the volume 5 times. So the total airflow (风机空载风量), or Clean Air Delivery Rate (CADR) you need = room volume x 5. For my front rooms, I need 210 x 5 = 1050 cubic meters per hour (m3/h) CADR. Since no single machine has this much power, I’ll need to buy a few machines.
  • Then you need to research air purifiers’ CADR — but here’s where it gets tricky: the published CADR applies only to max speed which is almost always not the speed you will be using 99% of the time. Most machines’ max speeds are far too noisy for normal use, and the speed you’ll actually be using may have airflow much less than the published CADR. The problem is that it’s hard to find published CADR for the lower speeds. I think as a general rule, you should cut the CADR in half to get a more accurate sense of how much coverage you’ll get.

Let’s continue with my example as a case study, now that I know I need to get to 1050 m3/h for my front rooms. Comparing a couple of very large machines:

  • Model A on max setting (5) = 783 m3/h. So I would need 1050/783 = 1.34 machines needed.
  • Model A on default setting (3) = 285 m3/h; 1050/285 = 3.7 machines needed.
  • Model B on max (6) = 510 m3/h; 1050/380 = 2.06 machines needed
  • Model B on medium (4)  = 289 m3/h; 1050/200 = 3.6 machines needed

Thus I could conclude that 2 Model A machines may be the most efficient choice for my needs, compared to 2 Model B machines, especially when it’s crazy bad outside and I want to crank up the machines to max speed for a few minutes. On the usual settings I would need an equal amount of machines, but they’re both equally expensive so I’d just start with two of Model A, take some data for a while with my Dylos, and see whether I need to buy a third one.

  • Thus armed with such information for your own rooms, now you can properly research which machines may be best for your needs. Generally you’d want a higher airflow than you really need, so you can use the machine at a quieter level and still get effective airflow. Or maybe two smaller machines combined would still be a better value than one more expensive machine.

Step 2: How Much Budget?

Only 200 RMB
Only 200 RMB (or 6 Starbucks lattes)

Not everyone can afford 12,000 RMB ($2,000 USD) for an air purifier, and the wonderful news is that nobody should be paying such exorbitant prices. Certainly when I arrived in Beijing eight years ago those very few early entry, imported brands served an invaluable service for expats and others. But now, there are many reputable brands making perfectly fine HEPA filters in China at a far more reasonable price point. For example, I’m pretty sure almost every student in China could sacrifice a few days of their Starbucks latte and buy the 200 RMB do-it-yourself air purifier. I also just published my own data proving that a slew of air purifiers under 1,000 RMB are perfectly fine for smaller rooms. I’ve tested most of the expat-famous imported models and yes, many are quite good, but I wouldn’t call most of them a good value for the money — not anymore. For example, here is a list from JD.com of HEPA machines under 3,000 RMB which are rated for room sizes over 50 m2, including models from famous international brands such as Westinghouse, Philips, and Panasonic.

Step 3: Research

consumersearch.com
consumersearch.com data

In terms of features (工作原理), I strongly feel that you do not need ions (负离子) or ozone (臭氧) which actually can cause more lung harm than help — especially in the cheaper machines. Even UV lights (UV灯) are a bit gimmicky. I also don’t care much about killing bacteria (杀菌) and in my home formaldehyde (除甲醛) isn’t a big problem. Really, all you need is an awesome HEPA filter which clearly mentions it eliminates >99% of particles (过滤灰尘/花粉 (0.3 微米)), plus a strong fan speed which reflects in a high airflow/CADR. My second rank would be an activated charcoal filter (活性炭 滤网) which absorbs the sometimes serious indoor gases called VOCs, especially formaldehyde (甲醛) and benzene (甲苯).

In terms of independent reviews, English readers should definitely start with consumersearch.com, which collects the most reputable reviews from multiple review sites such as Consumer Reports as well as reputable independent testers and also consumer reviews from Amazon. But this is limited data for us in China as many of the brands aren’t the same here. I dearly hope there’s a Chinese version of such a useful site for Chinese consumers! In the meantime, I’m aware of a couple of independent reviews in China which I’ve blogged about here; I also found another Chinese-only review here.

For other China-specific reviewers, I’ve blogged quite extensively about air purifiers and have reviewed many, which you can read here. My other favorite tests are from Thomas Talhelm, the creator of the 200 RMB Smart Air filter who also has extensive tests on his blog here.

The next level of research are the online shopping stores. Each model is overwhelming you with pretty pictures and a hard sales pitch, but it’s here that you’ll find the details of CADR, filters, room sizes, and extras such as carbon, formaldehyde, etc.

Step 4: Buying

In China, online shopping has quickly become the most efficient way to buy almost anything, including air purifiers (空气净化器). I recommend starting with Amazon China’s Clean Air Store, partly because on the left hand side you can instantly filter by square meters, price and features like HEPA. Also, for most English-speaking expats the Amazon store is much easier to use and very familiar to the USA version; they even have an English interface. My second choice online store would be Jingdong (JD.com), especially if you click on their own distribution brands (京东配送); they also have excellent filter options. My last choices would be Taobao and Tmall. Of course there are retail stores as well but for research and convenience, not to mention price, online is great.

Step 5: Testing

Dylos 1700 particle monitor
Dylos 1700 particle monitor

What good is spending all this money on machines if your indoor PM2.5 still isn’t under the goal 10 ug/m3 all the time? I’ve saved a huge amount of money and also know that my indoor air is clean because I invested a bit in a portable particle monitor. There are many brands but my favorite is the Dylos 1700, which also seems to be developing a fan club in China, led by the helpful FAQ on the fantastic website aqicn.org. Apparently you can buy online on Chinese sites but it’s cheaper (and probably safer) to get in the USA directly from them or Amazon. I hear that a lot of groups are pitching in to buy one and share, which is a terrific idea. The goal with this Dylos is to get the data on the left side of the screen (PM0.5 but actually more represents PM2.5) always under 3,000, which correlates to an AQI of 50 (which itself means PM2.5 concentration under 12 ug/m3).

Step 6: Maintaining

Before and after the airpocalypse
Before and after the airpocalypse

It’s quite shocking just how many people buy machines and actually forget to change the filters, essentially making them totally ineffective if the filters get too clogged. It’s not only crucial to replace the filters on time (all machine replacement schedules are different), it’s also helpful to frequently wipe or vacuum the outside of the machine to get dust off the prefilters. I’ve had a Blueair for a long time — and totally forgot about the plastic prefilter screen underneath the machine, which was totally clogged with dirt and I’m sure was dramatically lowering the airflow. That was embarrassing!

 My Bottom Line

There simply is no longer any good excuse for anybody in China, even those with limited resources, not to protect themselves with an indoor air purifier. I hope I’ve provided some helpful information for you to make informed decisions.

The Best Air Purifiers Under 1,000 RMB: My Test Results

(Click here to read my new guide to choosing air purifiers in China.)
Shanghai Skyline in thick Fog

Just how much, or how little, are you willing to pay for an air purifier? Here in China expats have been so accustomed to scandalously expensive air purifiers that we get suspicious if anything’s under 4,000 RMB — which still would be more costly than almost any high end model in America or Europe. But I just finished testing a half dozen models each under 1,000 RMB, and I’m now quite convinced that the lower-priced market can offer excellent value.

I’ve tested quite a few air purifiers during my eight years here in Beijing, and I honestly thought (hoped?) I was finished with the testing. But I recently was diagnosed with asthma, which really angered me as much as it scared me. In my anxious efforts to control my symptoms, I decided to ramp up my protection from air pollution everywhere:  I threw out my N95 masks and now only use N99; and I’ve totally reassessed protection at home and at work. My goal remains getting 100% of my daily exposure to PM2.5 under the healthiest target of 10 ug/m3 (AQI <50), the WHO’s official target which I blogged about last year and which I strongly feel should be everyone’s goal. I spent much of January testing more than a half dozen small air purifiers, all under 1,000 RMB, to assess which machines are best in small rooms, including my office as well as my bedrooms.

First, some background

Particles and sizes

I will repeat what I’ve said before: all you need is a good filter and a strong fan. Literally! Filter+fan. A decent filter is by far the priority, hopefully officially certified as a High Efficiency Particulate Arrestance (HEPA) filter, which in the US means 99.97% efficiency against PM0.3; the EU’s terminology is much more confusing, allowing HEPA ratings from 85% to almost 100% (more on this later). PM0.3 is short for “particulate matter of 0.3 microns size” which is essentially microscopic dust 10 times smaller than PM2.5; it’s importantly considered the most dangerous size that penetrates easiest into our lungs, causing the most harm.

While a good filter is crucial, it’s actually not super critical only to have the most awesome Hyper-Nano-Xtra-HEPA filter, with multiple 9’s that impress and overwhelm the consumer. Yes, that level of filtration is totally cool, but those extra 9’s very possibly are clinically irrelevant and only add cost, not value. Also, if the fan sucks weakly and isn’t circulating your room air at least 5 times every hour (known as ACH, “Air Changes per Hour“) then the total machine isn’t good. A machine with a 99.9999% HEPA filter but a tiny fan absolutely may clean the air less effectively than an 85% filter with a massive fan.

The same filter+fan concept applies for our ultra-expensive machines that many of us, including me, use at home for our big rooms. If they’re all humming away on a lower, noise-tolerable speed, then the air flow is much less efficient than their advertised Clean Air Delivery Rate (CADR), which refers to its max fan setting — most likely not the speed you’re always running it. Thus your rooms’ pollution may be much higher than you assume. CADR is a bit of a gimmicky test created by the industry, not a health agency, and a machine’s max setting is usually incredibly loud and which nobody uses for routine use, especially in bedrooms.  The CADR test in fact is only based on 20 minutes of data! It’s a totally impractical test for consumers in China as it tells us nothing about how we all use these machines here in China — always on, 24/7, at lower, quieter speeds which don’t impede conversations or sleeping. I completely don’t care if a machine wipes out all pollen and bacteria from the air; I want to know if a machine will protect me from dying from long-term exposure to small particles like smoke and dust — at a noise level that won’t drive me crazy. That’s the data we need — and of course don’t have, at least not from the manufacturers’ ads.

Smart Air vs. Famous Brands

Every good expensive machine is literally just an amazing HEPA filter with a strong fan. And that’s all you need — forget the rubbish about ionizers and ultraviolet light. A good machine absolutely does not have to be over 10,000 RMB, as Thomas Talhelm proved last year with his consumer-revolutionary 200 RMB do-it-yourself air purifier. His first machine was an off-the-shelf 90 RMB HEPA filter slapped with a velcro strap on top of a cheap plastic fan. And in his tests — which I confirmed on my own — it performed about as well, or better than, far more expensive machines (see his data to the right). And why wouldn’t it? His HEPA filter, if you hold a particle monitor over it, filters 100% of both PM2.5 and PM0.5; only IQAir has had similarly perfect results in my tests. You may not be ready for Thomas’ ungainly Smart Air models in your bedroom, but once you review his data you’ll certainly be much more open minded to the once heretical idea that an air purifier can be effective and affordable.

The machines

When I first arrived in Beijing over eight years ago, there were only a couple of choices for air purifiers. Now, hundreds of new models have flooded the market over the last couple of years, and I’m just as overwhelmed as you are when I search the Chinese shopping sites. There’s also very little independent testing or reviews (I wrote about one here, and here’s another). My search priorities were: price under 1,000 RMB; famous international brands > Chinese models; filter rated HEPA or darn close; fan strength flow rate (CADR) at least matching what my office needed (which is ROOM VOLUME x 5 ACH; thus 21 m3 x 5 = 105 m3/hour airflow). Another real plus was the ability to filter formaldehyde or VOCs, but that wasn’t my priority. Separate pre-filters also are helpful — but uncommon at this price point. I chose these:

midea philips panasonic air purifiers
Midea, Panasonic, Philips
  • Smart Air Original: 200 RMB; filters 99.9% of PM0.3; CADR unknown; covers 11-20 m2
  • Air-O-Swiss P320: 699 RMB; filters 99.97% of PM0.3; CADR 86 m3/h, covers 16 m2
  • Panasonic F-30C3PD-D: 599 RMB; filters 99% of PM0.3 and 89% formaldehyde; CADR 163 m3/h, covers 30 m2
  • Philips AC4025: 699 RMB; filters 91.2% of PM0.3 & 95% formaldehyde; CADR 127 m3/h
  • Midea KJ20FE-NH3: 750 RMB; filters 99.9% of PM0.3 & 87% formaldehyde; CADR 204 m3/h, covers 20 m2
  • Xiaomi: 899 RMB (or 1,000-1200 RMB on reseller sites); filters 99.3% of PM0.3 & 91% formaldehyde; CADR 406 m3/h, covers 48 m2

My Office Results

My clinic office was the main testing ground, a cozy 9.6 square meters floor space (21.3m3 volume). For such smaller spaces, a huge Blueair or similar flagship machine would be expensive overkill and take up valuable floor space; thus my urge to test smaller models. I tested these machines over my lunch breaks, at maximum speed, with the doors closed, usually after flooding the room with outdoor air and then closing the window. My key data points were at 10 minutes and one hour (50 minutes), measuring the percentage drop in PM2.5 and PM0.5 using my completely-worth-the-cost Dylos 1700 particle monitor. During the rest of the workday I would keep them on their more standard, quieter settings and do random checks. The results are all in the table below, but the take home points are:

  • All machines were generally effective at my key index of PM2.5 at 50 minutes of max speed: PM2.5 reductions ranged from 88-94%. Some got there a bit quicker, and at 10 minutes the Xiaomi’s clearly larger fan definitely shows off, already clearing 88% of PM2.5 with similar results for PM0.5. Again this shows the importance of fans as much as filters, and the Xiaomi’s CADR of 406 m3/h is double the size of the nearest competitor, the Midea.
  • The Xiaomi needs to be clarified a bit: its max speed button only lasts 15 minutes and then reverts to auto, so its comparatively lower 50 minute data is harder to compare to the others because only the first 15 minutes are on max. But considering how at 10 minutes on max it was the leader, one could assume it would do at least as well if it had continued on max.
  • The Air-O-Swiss clearly was the smallest model, with a CADR of 86 m3/h not close to the 105 that I needed, and it shows in the results. But it still wasn’t too bad. Most likely their larger 350 model would be more helpful — but it exceeded my admittedly arbitrary price rule under 1,000 RMB.
  • The Panasonic and Philips both did fairly well — it’s just really too bad the Panasonic’s garish orange color makes it totally unprofessional for me to consider using. The Philips’ green is more acceptable, especially for a kid’s room, but still it’s not ideal.
  • The Midea is a nicely handsome black and white model, something I wasn’t ashamed to show in the office, unlike the two above. Its larger size and fan speed also were borne out in the generally good results, especially with PM2.5.
  • The Smart Air Original — the do-it-yourself 200 RMB filter and fan — performed at least as well at its more expensive cohorts, although a bit less so with the PM0.5. It’s not professional-looking enough for me to use, but it’s still a great value for students and the like, and it’s far better than using nothing at all (read my earlier review).
  • Noise levels on max speed wouldn’t be tolerable all day for any of the machines, but on their quieter levels were generally all OK for an office.
Office-Air-Purifier-Test-Result
Air Purifier Results — Office (21 m3)

 

My favorites: I decided to test Xiaomi, Midea and Philips at home for the more important 8 hour results. I really like Xiaomi’s clearly larger capability thanks to its huge fan, not to mention its much classier, sleek look as well as its small footprint. I also thought the Philips and Midea were acceptable and not too out of place for an office.

My Bedroom Results

Xiaomi, meet Blueair
Xiaomi, meet Blueair

We’ve always used overly massive machines in our bedrooms, a Blueair 503 and IQAir Pro 150, and I thought now was the perfect time to challenge them against cheaper, smaller models (similar to my Philips test last year). This test was different than my previous tests, which had always compared indoor to outdoor air. This time, I wanted to see their efficiency over 8 hours, especially after a standard challenge by filling the room with particles, closing the doors and continuously monitoring while we slept. My particle test used essential oils in a vaporizer, which can raise the entire house’s pollution levels shockingly high and quickly. A secondary test was the final hour’s raw data: did it keep my indoor air in the green zone most of the time?

All machines this time were used on the quieter settings, not maximum as in the office tests. The great majority of tests were run in the larger master bedroom, which at 40 m3 (16 m2) needs airflow of 200 m3/hour. The smaller bedroom is 23 m3 (10 m2) and needs airflow >115 m3/hour.

Just for fun, I also compared these against an Airgle AG800, a much larger machine whose massive airflow of 763 m3/h easily should clean the air in such small rooms even at lower fan speeds.

The results, please

  • At the crucial 8 hour mark, most machines performed quite well. For PM2.5, Blueair led the way at 99.9%, just edging out Xiaomi’s sleep mode at 99.8%, with most others close behind in 98-99% range. For the smaller PM0.5, Blueair again topped out at 99.9%, closely followed by Philips at 99.6 and Xiaomi at 99.5%.
  • For short-term clearing within 1 hour, the Airgle did very well as you would expect for its huge fan, designed for much larger rooms. Otherwise, the budget machines from Xiaomi on auto and the Midea on low speed also did very well. (But the Xiaomi on auto comes at a slight cost, as its higher speeds to fight the incense are a bit louder and temporarily a bit distracting. And the Midea on low is a bit too loud for sleeping; fortunately the quieter sleep mode also did fairly well.)
  • Another useful metric is the final hour’s raw data (particles per cubic foot/100): My goal for PM2.5  is to always have the Dylos data stay under 50, which is roughly equivalent to 10 ug/3 (or AQI<50). The great news is that every machine’s final ranges were far under 50, including both cheaper models. For the trickier to control smaller PM0.5, the goal is a bit less clear but Charlie Thompson from my environmental testing company Environment Assured agrees that Dylos PM0.5 under 1,000 is the best equivalent to AQI<50. Using this cutoff, both the Philips and Blueair did extremely well, followed again by Midea and then Xiaomi in third. The larger machines from Airgle and IQAir surprisingly had some data over 1,000 — the only machines to do so.
  • In overall performance, all three cheaper machines certainly held their own, and none of them were obviously inferior even to the larger machines. The Midea posted impressive data even on their very quiet sleep mode. The Xiaomi also performed very well long-term and also was the best with short-term air clearing when in auto mode. The Philips also performed quite well with some very low raw data (but the outdoor air also was quite good that night, which helps a bit). For the three larger, far more expensive machines which on paper should have blown away their cheaper competition, only Blueair’s performance seemed obviously strongest, with the lowest raw data of all the machines in both particle sizes.
  • CORRECTION March 18: new data from the incredible Dylos FAQ at aqicn.org suggests that the left side number, PM0.5, actually is more representative of actual PM2.5 and the right side number represents PM10. Other data suggests that my PM0.5 goal of 1,ooo equals an AQI of 18 which actually is a bit of overkill; at 3,000 it equates to AQI of 53, just above the “green zone” of 50 (which equals a PM2.5 concentration of 12 in the USA). So anything under ~2,500 seems all to be in the green zone — which is great news as all my final hour raw data for PM0.5 was under 2,00 and often much less)
Air Purifier Results — Bedroom (40 m3)

My choices

For my office, my decision was fairly easy: I decided to go with Xiaomi due to performance, price and professional look. The Midea isn’t a bad second choice.

For the bedrooms, my decisions have been a lot harder. Since I already had machines, I’d need a really good reason to replace them. For the new bedroom, I’ve decided to use the Xiaomi. For our other bedrooms, I’m still deciding but know I will replace the IQAir and possibly also the Blueair with either the Midea or the Xiaomi.

I must talk a little bit more about Xiaomi’s air purifier, which is only on the market for three months but clearly may be very disruptive to the industry due to its novel design and incredible price. One very cool thing about Xiaomi which separates it from all the other machines is their app; their machines have built-in wifi which you can link inside their smart phone app and control the speed as well as get real-time data on the pollution inside the room, compared to the pollution outside (based on China MEP hourly data). This app even sends your phone an SMS telling you “the outdoor air is now clean and better than indoor air, it’s time to open the windows”! It also gives you real-time estimate of remaining filter life. It’s extraordinarily cool, even if a bit gimmicky — but this is my first foray into the exploding “connected home” phenomenon of intelligent, wifi-enabled home appliances, and I can definitely see the value in such data.

But I do have some reservations about Xiaomi, mostly because it’s a newish company known mostly in the mobile phone market for value, not so much top quality. Their HEPA filter is advertised as H11, which they claim is 99.3% efficient, which is not the highest rated top-line HEPA of 99.97%; but clearly their massive fan more than compensates for this, which accounts for its essentially similar, sometimes superior, results to the more expensive machines. As I said before, it’s the combination of fan+filter that’s the key.

Other negatives about Xiaomi are the newness of the machine. Since their air purifier is only a few months old, there’s no track record on maintenance or reputation. It’s also extremely difficult to buy on their own website due to their very unusual direct-selling marketing techniques; you can’t just order it, you have to first click to “reserve” and then on Tuesday at noon you and thousands of other people return to the website to buy, first come first served. I tried twice and they were sold out within one minute, so I was forced to use third-party resellers on Jingdong and Tmall — marked up, of course. This limited availability really disturbs me — what if the refill filters become hard to find?

These uncertainties are the main reasons why I didn’t replace my entire house with Xiaomi; otherwise, their price point and value are exactly the kind of disruptive innovation that the air purifier market in China desperately needs.

The Bottom Line (Finally!)

To summarize, I hope I’ve demonstrated that there are indeed many air purifiers far, far less than 10,000 RMB which may be perfectly adequate for your smaller room needs. Maybe 1,000 RMB models are a bit too weak, and for 1,500-3,000 RMB you can get a stronger fan and filter, especially from international companies with long track records such as PanasonicPhilipsWestinghouse and others.

Please note that my tests should serve as a guide, not as a strict recommendation, for your own decision-making. I also hope many readers also test their machines and share results with others, as Thomas does. My main hope is that people who currently don’t use any machine, mostly due to cost, will now realize they have far more options than they previously thought.

 

Other versions: Translation into Portuguese; Estonian

Indoor PM2.5 Under 10: A Noble Goal

 

window sealing PM2.5 pollution
Window sealing

I’ve recently become quite smugly satisfied that my home’s indoor air is always 80% better than the outdoor air, thanks to a quartet of air purifiers working 24/7. But I no longer think my 80% reduction is good enough, and I now have a much more ambitious goal — to keep my home’s PM2.5 concentration under 10-12 µg/m3, all the time — even when the pollution is crazy bad. This target of 10-12 µg/m3 (equivalent to an AQI of 42-50, using the US EPA AQI conversion) may very well be a tilting-at-windmills fantasy, but that is now my goal — backed up by science.

I mention this because my home’s environmental testing team has an indoor target of 10 µg/m3 which is the lowest I’ve heard. Before this, I was more familiar with an indoor air target of 35 µg/m3 (AQI of 100), which is what many testing agencies and air purifier vendors are advising. This 35 may be a fine goal for many, as long as you as an informed consumer realize that chronic exposure to 35 µg/m3 of PM2.5  still leads to long term health problems and is a compromise between economics and health, while under 10 truly is the number where health effects are approaching zero. Perhaps even more importantly, under 10 also is the official recommendation from the World Health Organization. Given all this uncertainty about ideal targets, I thought I’d try to walk my readers through the evidence, and you can come to your own conclusions as to which target you’d like to achieve.

Dirty pre-filter…

First, there actually is almost no such thing in the real world as a safe level of air pollution. Even with an extraordinarily low PM2.5 under 7 µg/m3 (AQI 30), the data shows an uptick in deaths, cancers and heart disease. As the WHO states in their 2005 WHO Air Quality Guidelines Global Update:

The risk for various outcomes has been shown to increase with exposure and there is little evidence to suggest a threshold below which no adverse health effects would be anticipated. In fact, the low end of the range of concentrations at which adverse health effects has been demonstrated is not greatly above the background concentration, which for particles smaller than 2.5 μm (PM2.5) has been estimated to be 3–5 μg/m3 in both the United States and western Europe.

The WHO updated this guideline in 2013, and with eight more years of research they are even stronger in their assertions:

Thresholds: For short-term exposure studies, there is substantial evidence on associations observed down to very low levels of PM2.5. The data clearly suggest the absence of a threshold below which no one would be affected. Likewise long-term studies give no evidence of a threshold. Some recent studies have reported effects on mortality at concentrations below an annual average of 10 µg/m3.

The WHO Guidelines for Indoor Air Quality (page 4) explain why their indoor air and outdoor air recommendations are the same:

The steering group assisting WHO in designing the indoor air quality guidelines concluded that there is no convincing evidence of a difference in the hazardous nature of particulate matter from indoor sources as compared with those from outdoors and that the indoor levels of PM10 and PM2.5, in the presence of indoor sources of PM, are usually higher than the outdoor PM levels. Therefore, the air quality guidelines for particulate matter recommended by the 2005 global update are also applicable to indoor spaces

Those italics are mine because this is very important for people to realize: your indoor air goal is the same as the outdoor air goal — and again, that means getting your PM2.5 under 10 µg/m3.

Much of the WHO’s research is based on a couple of famous, very large cohort studies involving hundreds of thousands of people, including the Harvard Six Cities Study and the American Cancer Society Cancer Prevention II Study. These studies show clear increases in death rates from all causes, as well as from heart disease and lung cancers, as air pollution rises. (It’s important to note that all of the data points in these studies, from dozens of cities, had a PM2.5 range from 10 to a maximum of 30 — far lower than most cities in developing countries across Asia now.) All make it very clear that after ~7 ug/m3, the health effects increase. Here’s the graph from the ACS Study:

Figure 2. Nonparametric Smoothed Exposure Response Relationship

Below is another graph from another famous article published in the New England Journal of Medicine in 2009, showing how life expectancy in US cities from 1997-2001 decreased with PM2.5 levels above 5 ug/m3:

Life Expectancies in 51 Metropolitan Areas in the US, 1997–2001
Life Expectancies in 51 Metropolitan Areas in the US, 1997–2001

Because of this and other data, the WHO’s Global Burden of Disease research uses a PM2.5 annual concentration of 7.5 µg/m3 as their counterfactual — the “control” number which would assume to have no health effects. All of their relative risk assessments, including their most recent reanalysis of household air pollution, use 7.5 µg/m3 as the ideal baseline — so why shouldn’t it be our personal goal as well?

Some may still argue that 35 µg/m3 is still the more reasonable goal, as even the WHO officially states that developing countries such as China could use looser guidelines, called Interim Targets. Interim Target-1 states an annual PM2.5 of 35 µg/m3 as the target for annual exposure. Also, this 35 is currently China’s target goal for urban areas (15 for rural areas). And getting under 35 is actually a significant achievement in places such as Beijing, with annual PM2.5 last year of 89.5 µg/m3. But as the WHO states in their Table 1 (below), a level of 35 is “associated with about a 15% higher long-term mortality risk relative to the AQG level” — which again is 10 µg/m3.

WHO air quality guidelines for annual PM2.5
WHO air quality guidelines for annual PM2.5

The data seems clear to me, and yet here we are in the trenches, still with many differences of opinion. I’m convinced of the science and also have no intentions of waiting years for stronger data and a more unified opinion. Besides, it’s just common sense, isn’t it? Lower is better. For the sake of my wife and new son, I want my home’s indoor PM2.5 under 10 — always. If I can get there, I can literally breathe easier.

Awesome Trio of Pollution Mask Tests: The Winners and Losers

Source: CDC PHILAny long-time reader of mine knows that I’ve repeatedly lamented the dearth of independent evidence regarding pollution masks. But now I finally have good news: since last month, two excellent mask comparison reports from consumer groups in China have been published, and many (but not all) of the questions I have had are now answered. Along with a third test from last autumn which I’ve already blogged about, these three reviews collectively give us the best guidance we’ve ever had about which masks are effective against PM2.5. All three reports are quite large and very thorough, testing dozens of models for fit, exhalation and leakage. One from last month is from another Shanghai consumers group which tested 38 masks, including Lvdun绿盾. But the granddaddy report is from the China Consumer’s Association which tested 37 masks, including Totobobo. The CCA is the team behind the annual March 15th consumers day. I sense that their report is as close as we’re going to get to an “official” independent Consumer Reports-style review. All three are only in Chinese so I’ve tried to translate and summarize the major findings below — many of which will surprise you.

The clear winners

If you look across all three reports, a couple of brands stand out. 3M definitely was a consistent performer in almost any category, and certainly remains my personal gold standard for masks. For example in the CCA tests below, almost every 3M tested received a full 5 stars for filtration过滤效果, the most important stat by far. But they also usually had top marks in resistance阻力 and leakage泄漏性. If you look at the second report last month from Shanghai, which has hard data on tested filtration efficiency 过滤效率实测值, 3M again does outstanding, getting 95% and above; the same goes for the third test from last year, again with filtration results over 95%.

3M definitely was a consistent performer in almost any category, and certainly remains my personal gold standard for masks. Another standout is the MASKin brand, which was just as solid as 3M in all three reports. Quite a few other brands also did well, but honestly as these were all Chinese brands that I don’t see around here, that data personally doesn’t help me too much. I think the take-home message here is that 3M is well known here in China, is now available in many places including 7-Eleven, and now has three independent reviews which prove not just effectiveness but comfort — and affordability. Plus, they have a slew of masks officially on the NIOSH list of N95-certified masks.

Another “winner” seems to be masks with exhalation valves, which usually performed well with filtration but especially in the other categories with improved resistance and decreased leakage. For what it’s worth, my current personal favorite mask is the disposable, foldable 3M 9001V which I grab from my local 7-Eleven. I find it very comfortable and effective, and the exhalation valve helpful. By the way, the 9001V straps go around the ears and not the head, and their filtration results were just as strong.

The clear losers

One famous Chinese brand, called Lvdun绿盾, was wildly popular last year but received decidedly mixed results in two tests. Their child’s size, the XS (绿盾PM2.5抗菌防尘口罩绿格XS秋冬塑料装), was a dangerous failure in the second report, filtering only 10%. Their washable adult masks tested only semi-adequately, with 65-86% efficiency in one study and only 2.5 stars (and no smiley face) in the CCA study. So I certainly wouldn’t recommend that brand at all, and given the disastrous results with the child size, I’m quite alarmed to see many children in China wearing this brand and being falsely protected. I certainly hope word spreads quickly to these parents.

Quite a few brands did miserably, with awful filtration and resistance, especially the cheaper, accordion-style surgical masks. All of this is clear proof that any mask that doesn’t fit well and allows air leakage is essentially worthless.

Reusable masks: The jury is still out

All three reports still didn’t test most of those most commonly used reusable masks in the expat community, including Vogmask, Respro and others. Only Totobobo was tested, and only in the CCA report — and it didn’t do so great. It only got a 3.5 out of 5 stars for filter efficiency, 4 out of 5 for resistance, and didn’t earn the smiley face for leakage. This is indeed a bit disturbing to me — but it’s just another clear shout out for even more independent testing.

In the meantime? To be quite honest, since I am a data geek and this is a HONCode-certified evidence-based blog, it’s now a bit difficult to really recommend any of those commercial, reusable brands at this time as a first choice. None of these are officially on the NIOSH-approved N95 list; none have any outstanding independent test results; only a few have outstanding fit test results but all of those are self-reported by the same companies that make the masks.

Clearly, if you follow the data, the best choices are obvious.

Study limitations

I certainly wish the CCA study provided more details, instead of a five point scale and happy faces — I want to see the raw data. And were these fit tests quantitative fit tests? How many samples of each? And with the second study, were the Totobobo masks cut down to size each face? What ages of children and how many tested the 绿盾XS? Having said all that, these certainly are major reviews which should help all of us make a bit clearer decisions about which mask to wear.

But we still have even more important questions to answer:

  • When should we wear these masks?
  • What ages should wear these masks?
  • How much will it protect our health, long term?

I suspect we will be waiting quite a few years for such WHO-level medical consensus and guidelines. I hope not, but I fear this will be the case. In the meantime, reports like these three are all we have.

 

REPORT #1: China Consumer’s Association 表2:比较试验对比结果表Comparison Tests (originals herehere and here)

标称品牌Brand name

标称样本Brand model

过滤效果Filter result

阻力Resistance

泄漏性Leakage

购买价格           (元/个)Price per mask (RMB)

阳光宜康

日用防护口罩

★★★★★

★★★☆

7.12

DELTAPLUS     代尔塔

自吸过滤式防颗粒物呼吸器

★★★★★

★★★☆

3

3M

自吸过滤式防颗粒物呼吸器随弃式面罩(口罩)无呼吸阀

★★★★★

★★★★

3.5

3M

9031颗粒物防护口罩

★★★★★

★★★★

3.96

每家玛

防尘口罩

★★★★★

★★★★

7.3

保为康POWECOM

新国际防尘口罩

★★★☆

★★★★★

1

IRIS爱丽思

爱丽思一次性立体防尘三层防护pm2.5口罩

★★★★

★★★★

1.9

3M

3M防尘口罩

★★★★★

★★★★

4.45

铭爱威

成人立体一次性口罩

★★★★

★★★

1.42

威尼

N95医用防护口罩

★★★★★

★★★☆

12.35

白元

一次性不织布口罩

★★★★

★★★★☆

2.71

海宁爱康

普通医用口罩

★★★

★★★★★

15

绿盾

PM2.5无纺防护口罩(成人型)

★★★★

★★★★

1.86

IRIS爱丽思

(无中文)

★★☆

★★★★★

3.99

适美佳

活性炭口罩

★★

★★★★★

0.58

爽蒂

一次性无纺布印花口罩(自吸过滤式防颗粒物呼吸器)

★★☆

★★★★☆

1.78

亲净

防霾抗菌口罩(一次性)

★★★★★

★★★★

3.3

稳健医疗

医用防护口罩

★★★★★

★★★★

8.5

3M

9332防护口罩

★★★★★

★★★★

33.9

MASKin

PM2.5专业防护口罩

★★★★★

★★★★

20

MASKin

617505防护口罩

★★★★★

★★★★★

7.6

JACKSON

自吸过滤式防颗粒呼吸器(非油性颗粒物防护口罩)

★★★★★

★★★★☆

5

DELTAPLUS     代尔塔

自吸过滤式防颗粒物呼吸器

★★★★★

★★★★☆

4.5

汤默臣

汤默臣PM2.5健康口罩

★★☆

★★★★

29.8

森浪

活性炭防护口罩

★★

★★★★

12.9

LifeVC

口罩PM2.5防尘抗菌口罩

★★☆

★★★☆

17

HL哈雷

哈雷舒适口罩

★★★

★★★★

24.9

绿盾

PM2.5抗菌防霾口罩

★★☆

★★★★

32

一罩绝尘

PM2.5口罩 防护型

★★☆

★★★★

32

华绣科技

纳米银抗菌抗病毒口罩

★★☆

★★★☆

27

维康Wecan

维康加厚保暖口罩

★★

★★

5

雪飞尔

雪飞尔时尚口罩

★★

★★★

2.5

雪花秀,        好姿尚

防尘、保暖口罩

★★

★★

6

3M

320D颗粒物呼吸防护套装

★★★★★

★★★☆

35            (滤棉2.95元/片)

totobobo

(无中文)

★★★☆

★★★★

199                (滤片11.9元/片)

CM朝美

舒适口罩

★★

★★★☆

25.5

CM朝美

9000型职业防尘口罩

★★★☆

★★★☆

2

过滤效率低于标准值、明示值和标识未标称执行标准滤料等级的产品名单

样品名称Sample Name

标称商标Brand

规格型号Model

生产日期/批号Testing date

过滤效率实测值Tested filtration efficiency(%)

防尘口罩

爽蒂

SD1076/KN95

2014.01.10.

26.3

随弃式口罩(一次性无纺布口罩)

爽蒂

SD3248/KN90

2013.09.25.

48.8

儿童口罩

爽蒂

SD2896

2013.12.26.

21.2

6002A职业防尘口罩(折叠式)

朝美

KN95

2013.09.02.

91.1

活性炭防护口罩

森浪

/

2013.04.10.

11.4

优至PM2.5防霾口罩

优至

180×95mm

2013.12.17./YZ13120000

65.9

无纺布口罩

啰啰

95mm×175mm

2013.04.11.

25.1

绿之源活性炭口罩

绿之源

175×90mm

2013.12.02.

7.1

适美佳活性炭口罩

适美佳

175mm×90mm

2013.11.16.

20.7

灭菌纱布口罩

skawamoto

成人型18cm×14cm×12层

有效期至20160513/SK06E13

9.2

普通涤纶防尘口罩

宜信

SC600C

2013.03./2013031801

0.0

绿盾PM2.5无纺口罩(成人型)

绿盾

/

2013.03.05.

64.3

绿盾PM2.5抗菌防霾口罩(轻薄透气型)

绿盾

绿盾PM2.5抗菌防尘口罩绿格F春夏纸盒装

2013.11.05.

86.3

绿盾PM2.5抗菌防霾口罩

绿盾

绿盾PM2.5抗菌防尘口罩绿格XS秋冬塑料装

2013.11.05.

10.3

竹炭健康口罩

健怡

/

2013.12.10.

47.6

舒适平面口罩

健怡

17.5cm×9cm

2013.08.28.

55.3

一次性平面五层无纺布口罩(成人5片装)

/

NPK-5PM

2013.11.26.

65.5

伊藤の良品PM2.5TM防护口罩

/

无纺布17cm×9.3cm×3层

2013.04.18.

17.0

伊藤の良品PM2.5TM防护口罩

/

23cm×14cm

失效日期:2016.11.02. 有效期;3年

10.7

防尘口罩(依恋防霾透气口罩)

依恋

/

/

16.6

名典上品四层活性炭口罩

名典上品

175×90mm

2013.04.10.

44.7

哈雷舒适口罩

哈雷

L型

/

16.8

一次性活性炭四层口罩

维康

/

/

37.7

竹炭防护口罩

维康

长18*宽7cm

/

12.8

哈雷舒适口罩

哈雷

15×12(正负0.5)厘米三岁以上儿童使用

/

21.4

自吸过滤式防颗粒物呼吸器 随弃式面罩(口罩) 无呼气阀

3M

9001/KN90

2013.05.20.

94.9

MASkin 活性炭粉尘口罩

MASkin

6135/5只/泡壳

2013.04.16.

95.0

N95型口罩

MASkin

8265/6只/彩盒

2013.04.16.

95.5

随弃式面罩

吉可

1500/KN95(带呼气阀)

2013.12.09.

97.9

自吸过滤式防颗粒物呼吸器 随弃式面罩(口罩) 无呼气阀

3M

9502/KN95

2013.08.09.

97.3

自吸过滤式防颗粒物呼吸器

乐求

SL-A II类 KN95

2014.01.10./14-006

97.3

自吸过滤式防颗粒物呼吸器

沪兰

JF-2-3型 KN90

2012.09.11.

99.9

自吸过滤式防颗粒物呼吸器

zhongzhi

ZH3031

2014.01.24.

95.0

自吸过滤式防颗粒物呼吸器

安适达

5210

2013.03.01.

96.6

自吸过滤式防颗粒物呼吸器

地球

1068型/随弃式面罩

2013.05.

96.7

杯型口罩

朝美

8011-1/KN95

/

96.4

自吸过滤式防颗粒物呼吸器 无呼气阀

LACKSON SAFETY

63201 KN90

2013.05.13.

95.3

亲净TM儿童口罩

亲净

87*145(±5)mm

2013.07.05.

97.4

Report #3: From Shanghai Consumer Rights Protection Commission: their article; their raw data (Excel file); my earlier review here); my edited/translated data below:

Highest Rated Disposable Masks
Highest Rated Disposable Masks

 

Worst Rated Disposable Masks
Worst Rated Disposable Masks

 

My Personal Fit Testing: Here’s the Best and Worst Pollution Mask For Me

portacount fit test N95 PM2.5 respirator mask
Testing the Respro Techno mask

Which mask is the best against pollution? I can’t really answer that for everyone, as our faces have different sizes and shapes. I’ve recently shared results from three large tests, which unfortunately didn’t review many of the consumer masks I’ve used. But I can now tell you exactly which of those popular masks is perfect for me, and maybe we all can learn a bit from my adventure. Here’s my tale.

In my seemingly never-ending quest for the best research on masks, I recently started to correspond with the research team at 3M, and during our conversations they very nicely offered to let me use their TSI Portacount Pro+ machine at their testing lab in Beijing (with no oversight of my results or article). This is the most widely used machine to officially test a mask’s effectiveness on a person’s face, and on a nicely smoggy day (another typically hazardous AQI over 150) I tested nine masks to find out which worked best for my face: three 3M models; Totobobo; Vogmask; Respro Techno; I Can Breathe Honeycomb; Lvdun 绿盾; and a surgical mask.

We performed a quantitative fit test called a total leakage test on all nine. This test measures exactly what you and I want to know: the ratio of particles larger than 0.3 microns (PM0.3) inside the mask, compared to the particles outside the mask. To perform each test, you punch a hole in each mask and stick one tube in it and another tube outside. This ratio of outside/inside air is called the Fit Factor, and while a proper “pass” would be a Fit Factor over 100, which means an efficiency of 99%, any Fit Factor over 10, which means efficiency of 90%, is also pretty darn good, and a much more achievable target for real world use. This is also called the workplace protection factor by OSHA in the USA, and is the target for anyone who must wear a similar mask for their job. For me, my goal for success was a Fit Factor over 10, and super success would be Fit Factor over 100.

quantitative fit test report particle respirator N95 PM2.5 pollution mask
Fit Test Report example

The test itself is easy and only takes ten minutes, using a series of positions, each lasting just over one minute: normal breathing; deep breathing; head turning side to side; head up and down; talking; grimacing; bending up and down; and normal breathing. Before each test, to make sure you have a proper seal on the mask, you do a user seal test, in my case doing a negative pressure test. This quick check actually is something all of us should perform each and every time we put on our masks: you cup your hands on each side of the mask and breathe in quickly. Your mask should cave in a bit from the negative pressure; if it doesn’t, the seal isn’t tight and you need to adjust.

Enough with the details: what worked best for my face — and what was awful? Without further ado, here’s my Excel graph showing the results, in order of efficiency from best to worst:

 

Total particle test results
Total particle test results

The best mask for me

There was only one true winner with a Fit Factor over 100, technically “passing” with efficiency far above 99%: the 3M 9332, a disposable which is certified FFP3 in Europe (N99, essentially). With an incredible Fit Factor result of 240 (99.6% efficiency), this was almost too good, as I found it a bit less easy to breathe than with others. But still, on crazy bad pollution days, I think I’ll be using this one. Besides this model, three others passed the threshold Fit Factor over 10 (90% efficiency): the 3M 9501 at 97%; a Vogmask with 95%, and a 3M 9001V at 92%.

pollution masks N95 respirators
My nine models tested

The middle ground

In the middle, with efficiencies in the 80% range, in order were I Can Breathe’s Honeycomb mask at 87%, then the Respro Techno at 85%, followed by my second attempt with the 3M 9001V at 84%, then Tobobobo at 80%.

The worst for me

The worst mask of all was the most popular reusable consumer mask in all of China last year, the Lvdun 绿盾 mask. At only 57% efficiency, this 32 RMB mask was even worse than a 1 RMB surgical mask from my clinic, which did surprisingly not horrible at 63%. Lvdun’s poor results were similar to other poor results from a couple of Chinese consumer group reports that I’ve already discussed in an earlier article. I’m quite astonished that this Lvdun mask is such a good seller in China, and I feel a twinge of anxiety every time I see an adult or child wearing one of these.

My bottom line

Don’t forget that every face is different, and many studies have shown that one size does not fit all, unfortunately. So my results don’t mean the same mask will work the same for you. Even the same mask can fit differently on the same person on different attempts, as I demonstrated with the 9001V.  For me, I found this testing invaluable and I certainly am much more reassured with what I already knew: the 3M brand is by far the most consistent, evidence-based, internationally proven and researched series of masks for me — and maybe for everyone. Their dozens of models have been fit tested millions of times over the last few decades in workers across the world, and I can’t think of any other mask company which even comes close to their reputation and experience.

My everyday mask is now their 9501, which I can grab at any 7-Eleven, only costs 6 RMB, fits flat in my pocket and lasts at least a week. At over 97% effectiveness, on a crazy bad day of PM2.5 concentration of 500 ug/m3, the air inside my mask is around 13 ug/m3 — just within reach of my ideal target of 10. The 3M 9332 would easily get me there. The next time the airpocalypse hits and it starts raining down hellfire, frogs, and PM2.5, I’ll be biking to work as usual, safe and snug inside my mask, wearing my helmet and humming along to Air Supply’s Greatest Hits.

Regarding all of the commercial masks popular especially among expats, I honestly was disappointed in their general results for me, none of which were better than 90% — except for Vogmask. Respro’s Techno filter is officially FFP1 in Europe, which means 78% efficiency, and it actually did better than that on my face. But given how much more expensive it is, I certainly wouldn’t consider this a good value for me at all, especially if a 6 RMB mask can get far better protection. It certainly didn’t help that I found it surprisingly uncomfortable. And in general, 78% protection in China just isn’t good enough, and I don’t think anyone in China should consider a mask certified only FFP1 when so many other masks do better than that. Even on an average Beijing day of 90 ug/m3, an FFP1 mask at best would still give you 20 ug/m3, which is still far above my ideal of 10 and under (equivalent to a healthy AQI under 50).

I was also a bit disappointed with Totobobo, but the result is fairly consistent with a recent test from the China Consumers Association, which only gave it 3.5 out of 5. I find their manufacturer’s suggestions to custom fit their masks with scissors or boiling water quite onerous and certainly at a disadvantage when many other masks are far more effective right out of the package, requiring no customization, at a far cheaper price. The I Can Breathe Honeycomb mask wasn’t so bad, and is very comfortable, but again there are other masks which do far better and are much cheaper. I Can Breathe also has no official certifications, which I feel is another disadvantage. Vogmask was the only one that did very well, but they still don’t have any official ratings nor any large independent tests, so I would consider this my first second choice — but still a second choice. I suppose for now it would be my first choice for my toddler, but I am definitely uncomfortable relying on only one test result from one 8-year old boy. But at least I know it’s far superior for my toddler than Lvdun’s extra small mask, which in previous independent tests performed dangerously ineffective at only 10% efficiency.

I’m starting to think that this entire new industry of pollution masks for consumers should be regulated in order to prevent false health claims, and especially to protect our children from using dangerously ineffective masks. I now find it hard to seriously consider any mask which doesn’t have any official certification (N95 or N99 from USA, FFP2 or FFP3 from Europe, KN95 from China) as well as independent test reviews. I certainly hope that the consumer mask companies continue to nobly rise to the challenges, improve their designs and try to get certifications. In the meantime, I’ll stick with my 3M.