Fine Dust Masks – What You Need to Know

  • 15 min read
Air Pollution

The wrong fine dust mask, or one worn incorrectly, is only a waste of money. EVERY DAY I see people wearing masks that aren’t actually protecting them at all.

I recently published an article discussing the air quality in Korea and how to deal with it. After sharing the post on Facebook, a lot of people disagreed about the usage period of disposable masks. Many people said that they use them for a few days in a row and that they are still effective after a few days of heavy pollution.

I realize there is a lot of confusion out there as to how specifically the masks work, and I want to discuss which masks are the best, how long they last, and more, in this post.

Which masks actually protect you from fine dust, how long do they last, and how should they be correctly worn? What is the best fine dust mask?

Recommended Dust Masks

Air pollution is quickly becoming a leading cause of death worldwide. Learning how to protect yourself if more important than ever.

If you want me to get straight to the point and recommend a mask then here is the short answer. These masks will protect you from air pollution and keep your body safe.

However, there is a lot more that is important to know – how long do the masks last? How do you wear them properly? (If you don’t, then your body is still being severely damaged). To learn these answers and more, read on!

For the best protection look for N95+ and KF94 masks. To learn more about these ratings and what they mean, continue reading.

N99 Masks – Best Protection

3M 9332 (Coupang) | Base Camp N99 (Amazon) | PM2.5 Anti Pollution Mask (Coupang)

N95 Masks – Good Protection

3M 9010 (Coupang) | 3M 9010 (Amazon)| Drager x-plore 1350 N95 Mask (Coupang)

Reusable Masks – My Personal Recommendation

Cambridge Mask N99 (Coupang) | Cambridge Mask N99 (Amazon) – This is the mask that I personally use and recommend for reasons stated in the article

Reusable Masks – Other options

Vogmask N95 (Coupang) | Vogmask N95 (Amazon) | Muryobao Anti Pollution Mask N99 (Coupang) | Muryobao Anti Pollution Mask N99 (Amazon)

This site contains affiliate links to products. I may receive a commission for purchases made through these links. Affiliate Disclaimer.

Different Types of Masks

‘Common surgical masks are meant to catch the wearer’s own bodily fluids, such as saliva and nasal discharge, and prevent any infectious liquid droplets from spreading to others. They are not designed to protect you from inhaling airborne bacteria, viruses and fine particles.’¹

Surgical Masks

Surgical masks are one of the most common mask types that I see people wearing every day. While many people wear these to protect both themselves and others from sickness, there are also many who wear them with the assumption that they protect from fine dust.

Fine Dust Masks - What You Need to Know 1

Surgical Masks such as the one above are ineffective at preventing fine dust inhalation.

This is not only untrue but something that is potentially harmful to assume. Surgical masks have two straps that sit behind your ears, and these are ineffective against fine dust for a number of reasons.

Not only is the material not meant to prevent the penetration of fine dust, but the masks also don’t create a seal on the wearers face. Fine dust can simply enter the mask through the gaps around the wearers face.


Respirators, on the other hand, are masks meant to prevent fine particles from entering the body of the user. These respirators are rated N95+ (with the number representing the percentage of particles prevented by the mask. I.E, an N95 mask is effective at preventing 95% of particles from passing, while an N99 mask is effective against 99% of fine particulate matter).²

Basecamp N99

Respirators such as the Base Camp N99 are made to prevent the wearer from inhaling fine dust 

R rated masks (R95+) are also available and are resistant to oil. However, these aren’t needed for the general user in Korea. If you bike often on roads (behind other vehicles especially), then consider purchasing R masks to protect from the harmful gasses emitted by the vehicles sharing the road.

Amston N99 Mask

The Amston N99 mask is another great option.

It is worth noting, however, that KF and N rated masks only protect you from fine dust. They do not protect from other ozone pollution such as gases.

‘N95 masks do NOT protect you against chemical vapours, gases, carbon monoxide, gasoline, asbestos, lead or low oxygen environments.’³ Learn more about the different pollutants in the air.

How Long Can I Use a Single Use Mask For?

‘NIOSH states that it is not always necessary to dispose of the FFR (filtering face-piece regulator) the first time it is removed.  In most workplace situations, an FFR can be reused as part of an employer’s respiratory protection program. Safe FFR reuse is affected by a number of variables that impact respirator function and contamination over time, says NIOSH.

Unless the respirator manufacturer identifies a specified duration of use—for example, single-use only, or the employer’s respiratory protection program excludes reuse—users can wear an FFR until it is damaged, soiled, or causing noticeably increased breathing resistance.

However, there are limitations for reuse. Perhaps most importantly, the FFR should be used and reused only by the same wearer. Also, between uses, the FFR should be stored in a way that protects it from damage, dust, contamination, sunlight, extreme temperatures, excessive moisture, and damaging chemicals.

In addition, since most disposable FFRs do not have solid frames, they should be stored in ways that prevent deformation of the facepiece, straps, and exhalation valve, if present.’⁵

Factors That Impact Mask Lifespan

The level of pollution is the biggest influence on a mask’s lifespan.

It is also very important to remember that the reusing of masks depends heavily upon a few factors.

Air pollution level, humidity, and amount of physical exertion. After a day of high pollution (such as days with an AQI rating over 250), masks should only be worn for a single day. However, on days of lower AQI ratings (such as 50), these masks can be reused for a few days or until breathing becomes difficult.

Physical exertion can also vary the lifespan of a respirator, and if you are running or biking with a mask, consider replacing it every day or two – even in days of light pollution. Finally, humidity greatly affects the effectiveness of a respirator, as once a mask becomes damp it quickly loses its filtration qualities. On high-humidity days, change your respirator every day.

When to Throw out a One-Use Mask

As the N95 mask gets clogged, it becomes more difficult to breathe. When this occurs, throw it out and use a new one. Discard the mask if it is wet or dirty on the inside, if it is deformed, or if the filter is torn. A deformed mask may not fit properly. An N95 mask cannot be cleaned or disinfected.⁶

In short, respirator masks can be reused. However, after the first usage (or after 8 hours), they are no longer guaranteed to perform to the NIOSH standards. It is worth keeping in mind, that while masks will degrade, they can normally last a few days of light-medium usage.

A variety of factors can influence how long the respirator is usable for. Oil and humidity drastically affect the performance of masks and decrease their lifespan. If you cycle lots (on the road, behind vehicles), or are out in humid weather, you should be changing your mask regularly. If the mask ever gets wet, dispose of it and find a replacement.

It is also worth noting, how you touch the mask will affect how effective it is. When putting on and taking off the respirator, make sure not to touch the material in front of your face (either on the outside or inside of the mask). Instead, use the straps to adjust the mask and put it on. Before removing the mask, make sure to wash your hands as otherwise fine dust particles can transfer to the respirator.

When storing the mask, make sure it isn’t placed in the sun, and that there is nothing around to put pressure on the mask and deform it. Deforming the mask will reduce its effectiveness by decreasing the fit and ruining the seal. Further, have one mask per person, and don’t share masks. Once worn, the mask is shaped to the face of the wearer. Allowing others to wear the mask will break this shape and will once again, decrease effectiveness.

KF Ratings vs N

NIOSH (N) masks VS KFDA (KF masks). Hyejung Jung, Jongbo Kim, Seungju Lee, Jinho Lee, Jooyoun Kim, Perngjy Tsai, Chungsik Yoon. Comparison of Filtration Efficiency and Pressure Drop in Anti-Yellow Sand Masks, Quarantine Masks, Medical Masks, General Masks, and Hankerchiefs. 2014.

The NIOSH only certifies masks which surpass a rating of N95. No mask preventing less than 95% of fine dust particles will be given a rating. As such, you can be sure that you are getting a quality product if it has the N rating.

KF masks, on the other hand, are rated by KFDA (The Korean Ministry of Food and Drug Safety, now named the MFDS) and are unique to Korea. These masks are rated similarly to the NIOSH rated masks, with KF80 being the minimum rating. However, with KF80 rated masks only preventing 80% of fine particulate matter from penetrating, it is recommended that you wear KF94, N95 or above.

When NIOSH and KFDA masks were compared to each other, both performed well. ‘All tested quarantine masks satisfied the maximum penetration criterion of 6% (KF 94)’.⁴

While similarly rated masks in both the KFDA and NIOSH systems perform similarly, it is noted that NIOSH masks perform better at higher ratings (N95+). Considering that KF ratings don’t surpass KF94, N rated masks are also capable of higher ratings and N99 should be used when possible.

How to Correctly Wear a Respirator

When putting on a respirator it is important to keep physical contact with the face-piece to a minimum. When touching the mask, try to restrict hand contact to the strings. Contact with moisture decreases the effectiveness of a mask, and oil and moisture from your hands can easily affect the usefulness of the material.

Holding the straps, pull the mask onto your head (or over your ears) with minimum contact to the mask itself. Adjust the wire nose-piece to make sure that it fits snugly and that there is no gap around your nose. Finally, perform air pressure checks to make sure that the mask isn’t leaking anywhere.

How to Make Sure the Mask Fits

How to Properly Put on and Take off a Disposable Respirator. For full details, visit the link.

Do a user seal check, including both positive and negative pressure checks, to verify that you have correctly put on the mask and adjusted it to fit properly.

  • Negative pressure check. Place both hands completely over the mask and inhale sharply. Be careful not to disturb the position of the mask. The mask should pull into your face. If air leaks around your face or eyes, adjust the nosepiece and straps and repeat the positive pressure check.
  • Positive pressure check. Put your hands over the mask and breathe out sharply. If your mask has an exhalation valve (like the one pictured above) be sure to cover the exhalation valve when you exhale. No air should leak out of the mask if it fits properly. If air leaks out, re-adjust the nosepiece and straps and repeat the negative pressure check.⁷

If both of the pressure checks succeed without air leakage, then the mask is protecting you from fine dust! If on the other hand, air leaks no matter what you try, consider purchasing a new mask in a different size. It is worth mentioning though, that these masks aren’t designed for people with facial hair or for children. Children’s masks are available, but rarely are they as effective as adults masks. Facial hair will also reduce the effectiveness of respirators and there really is no other way around this except to remove the hair.

Which Fine Dust Mask is Best?

My personal mask preference is a reusable Cambridge Mask.

Unless you have a specific need for a moisture-resistant respirator, any mask of KF94 or N95 plus is very effective at stopping particulate matter from entering the respiratory system. N99 masks are of course better, however, they are also harder to find. Some great N99 masks are the 3M 9332, Base Camp N99, and PM2.5 Anti Pollution Mask.

Reusable Masks

There are also masks available that can be used for longer periods of time. Masks such as the Cambridge ones last over 200 hours and are rated N99. These masks are more expensive than disposable ones, but for the extra length of use, they are often worth it.

Cambridge Mask

Cambridge Mask.

There are many competitors out there such as Vogmask and Respro, and these masks are also highly regarded. While I have no affiliation with any of these companies, I personally use a Cambridge Mask and highly recommend it. From my own research, I found it to be vastly superior to Vogmask as it also prevents the penetration of 99.7% of bacteria and viruses.⁸

Cambridge Mask also had more extensive testing and as such, I trust it more. Respro is an option that I didn’t look much into as the availability at the time of my purchase was limited. If you want a reusable mask, then Cambridge Masks are the way to go.

Some other options are Vogmask N95 (Coupang) | Vogmask N95 (Amazon) | Muryobao Anti Pollution Mask N99 (Coupang) | Muryobao Anti Pollution Mask N99 (Amazon). All of these masks are reusable and carry the N95 or N99 rating.

Single-use Masks

If you are not interested in reusable masks, then there are also many great disposable options available. While any mask with a NIOSH rating will perform well, there are many options available. 3M masks consistently perform well and are recommended by many. 10 packs of these masks can usually be purchased and these packs allow for a few weeks of use. There is even a 50 pack of 3M N95 masks available on Amazon.

Fine Dust Mask

Single-use masks can generally be bought in packs of 20+. An example is the 3M 8210.

Many KF rated masks can also be found, and while these are still effective, most KF masks are only rated at 80. The best that KF has to offer is only KF94, and while 94 is still very effective, I feel far more comfortable knowing that I am wearing an N99 or N95 mask.

If a mask doesn’t have a KF or N rating, don’t even bother purchasing it. The other masks that are available are usually for bacteria, and they are made to prevent the spread of sicknesses. These masks will do very little to protect you and aren’t worth purchasing.

There are many other masks available, and many of them offer great dust protection. Really, the NIOSH and KFDA ratings are the keys to finding an effective mask. From there, it is a matter of finding the best fit for you.

To keep this article within a reasonable length however, my broad recommendation is an N95+ rated 3M respirator. If you are looking for a reusable mask, then make sure to do research first and to look at other reviews. It is important to find a mask that fits correctly and is comfortable.

Learn More

It is important to always consider and monitor the air quality, or really anything, that can potentially harm your health. However, it can be hard to understand the AQI (Air Quality Index) readings and what they mean. To learn more, I recently wrote this post to help with everything there is to know about air quality in Seoul.

If you have any questions or comments about respirators, the air quality, or Seoul, please don’t hesitate to let me know. You can get in contact with me by leaving a comment below, or by contacting me here.

This post contains affiliate links which allow me to make money at no extra cost to you. I have no affiliation with Cambridge Masks, I am just a happy user of their product.










4 thoughts on “Fine Dust Masks – What You Need to Know”

  1. Hi again, Do you have access to flu vaccines? or is the mask you wear enough of a prevention in picking up viruses, personally i would think so because viruses are also spread by hand to mouth. Are medications for your asthma very expensive?
    And about masks, do you wear them at all times when outside? all year round, or is there a season when the pollution is lot less harmful?

    1. I am unsure about the vaccines as I have never had to have them here. But in regards to the masks, yes, they are effective at preventing viruses. I could be wrong here (don’t quote me), but viruses attach to other particles and they spread via non-viral particles. As such, since an N99 mask prevents 99% of particles, it would also prevent 99% of the particles that viruses are attached to. The masks are also effective at preventing bacterial particles.

      Luckily asthma medication is very cheap with NHI (National Health Insurance) and they are definitely cheaper than NZ. Although I can’t remember the specific cost right now.

      About the masks – Me (and nearly all others) don’t wear them that often. If you follow the WHO guidelines the values considered dangerous are as follows:

      10 μg/m3 annual mean
      25 μg/m3 24-hour mean
      20 μg/m3 annual mean
      50 μg/m3 24-hour mean

      However, nearly every day in Seoul is over these values. According to the WHO, 91% of the world’s population lives in dangerous air. While really masks should be worn every day, it is considered more of a relative risk. Since the air is always bad, masks are usually only worn on exceptionally bad days. I tend to wear mine whenever the AQI is over 120 (the average is about 70). These days happen maybe once or twice per month.

      Interestingly, Spring brings the worst pollution. Due to the direction the winds blow in Spring, the air from China hits Korea and makes the air quality terrible. Otherwise, all of the other months can range greatly from day to day. Rain is great though, as it cleans the sky for the next day.

    1. Hey Jayce. I am assuming that you purchased the reusable mask shown in the image, rather than the disposable masks?

      If so, masks like this tend to last 200-300 hours. I am unsure on that mask specifically, but that seems to be the standard for reusable masks. The lifespan can be affected by a few factors but on a day of medium pollution in Seoul (AQI 100-150) it will last a couple of hundred hours at least.

      The best way to tell is when breathing becomes difficult. Over time, you will notice that breathing becomes more difficult through the mask. This is a good indication of when you will need to replace it.

      Unfortunately finding information on each mask can be very difficult (especially for Korean brands). That’s why I talked about Cambridge mask and Vogmask in the post. While there are lots of great dust-masks out there, these two brands provide the most clear information. Cambridge masks last 300 hours in medium pollution (, and Vogmask advertises their masks as lasting for 4-5 months (

      Unfortunately, these masks tend to carry a premium compared to Korean brands/unbranded masks. I did find an option on Coupang for 25,000KRW though which isn’t too much more than the mask you mentioned.

      I hope this helps you! If you have any further questions please feel free to ask.

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