Gas Mask Filter Buyer's Guide [2022 Update]
We can survive three weeks without food, three days without water, but only three minutes without breathable air.
That's why protective gas masks can be a lifesaver in case of disasters like terrorist attacks or nuclear meltdown. But you might not realize that without the right filter, even the best gas mask is useless.
Because modern 40 mm gas masks filters are specialized to deal with any number of hundreds of toxins and airborne contaminants-ranging from chemical to biological, radiological and even nuclear-all while fitting the same gas mask.
A single filter can protect you from all of the contamination from a nuclear meltdown for forty full hours, while another filter could help you safely navigate the smoky environment of a house fire to reach safety.
But each gas mask filter has its limitations…
Each filter has a shelf life, classification, specs and price. The craftsmanship of their construction matters just as much as the science behind their effectiveness. Creating a working gas mask filter takes specialized knowledge of how to impregnate carbon with a key balance of metal salts and then treating the blend with chemicals to pass strict testing requirements.
These complicated factors are often overlooked by new and even experienced buyers. That’s a mistake that can cost you time and money…or something even more important.
So, we’re going to look at everything you need to know about protective gas masks filters: from their practical function and specifications to the logistics of storing them and, should the need arise, putting them to potentially life-saving use.
We’ve assembled all the research you need to make an informed decision and give your family the protection they might need.
Let’s get started…
TABLE OF CONTENTS
Gas Mask Filters 101
Top 4 Gas Mask Filters of 2020
Filter Storage & Shelf Life
Filters to Avoid
Gas Mask Filter FAQ
Gas Mask Filters 101
The history of gas masks and how gas masks filters became practically universal is something we've already covered in our Gas Mask Buyer's Guide, so we won't delve into that here.
Modern protective gas masks filters, on the other hand, are truly a technological marvel.
Gas Mask Filter Function Basics
Gas masks filters rely on three chemical processes to provide clean air in even the most toxic environments.
is the most basic process, separating solid particles and aerosols from breathable air using media like charcoal.
happens when the captured substance condensates into the porous structure of the filter's activated carbon. This process actually captures gas molecules as they pass through, neutralizing threats.
happens when physical adsorption meets the impregnated chemicals in a filter's activated carbon. During this process, even the most toxic elements can be momentarily captured, forced to interact with impregnated elements and immediately neutralized.
Due to the precise nature of filter construction and the mechanics involved, there are a few key classes of filters you'll notice immediately:
1. Particle filters
use basic filter media like Class 16 fiber paper to filter out common toxins. They're basic and affordable due to their simple construction. These are more often used for construction and demolition.
2. Gas filters
use the impregnated carbon we talked about above to provide more comprehensive protection from airborne threats. Note that these gas filters typically lack the mechanical filter media of particle filters.
3. Combined filters
are, as the name implies, a combination of gas and particle filters to provide more comprehensive protection from a wider variety of threats than either can provide alone.
4. Special filters
like most CBRN filters on the market today, take protection to an even higher level, with safeguards against things like organic substances with low boiling points, including mercury, COx, NOx and radioactive metal iodide.
To produce a modern gas mask filter takes unprecedented skill and expertise. Fortunately, it couldn’t be any easier to put one to use.
Gas masks filters are easy to carry, use and store, with a shelf life that can stretch into decades, and depending on the specific filter, they can provide up to 40 or more hours of practical protection from airborne contaminants and toxins. Any worthwhile gas mask filter will have these details laid out in the included documentation. This can make logistics straightforward, as you’ll see in the Storage & Shelf Life section below.
Many filters have the same round shape and size that you probably already know. Inside, each filter has a unique combination of chemical and mechanical media to filter out particulates and provide the user with breathable air even in extreme environments.
Due to the complicated nature of how these filters are built, there’s no “one size fits all” solution, so filters are classified based on the protection they provide—typically designated by a series of numbers and (sometimes) color-coded bands (per standard EN 14387+A1). More on that in Filter Classification below.
It’s important to note that these color-coding systems are primarily used for easy identification by industrial workers, so you won’t see them on all filters (they’re noticeably absent on the NBC-77 SOF filter, for example, which is all grey). Most (but not all) of the mask filters you’ll see on the market today are threaded to screw into gas masks with one of two popular formats known as 40 mm NATO and GOST.
As the name implies, 40 mm NATO is the filter standard used by NATO and US armed forces (conforming to the specifications of STANAG 4155 EN148-1), making these filters a popular and readily available choice for law enforcement, private military contractors and civilians.
For 99% of concerned civilians, 40 mm NATO filters are what you want. It’s an actively policed and maintained format that’s associated with a raft of other NATO gas mask filter requirements and regulations—so even if you’re paying a few bucks more, you know what you’re getting. We’ll cover a few of the best NATO filters for your money in our Popular Filter Choices section below.
GOST, on the other hand, is the competing Russian standard for gas masks and filters. Filters like the VK-450 can be GOST-certified while using the standard NATO 40mm threading, giving you a practical and budget-friendly alternative that still works with your favorite gas masks.
GOST testing is practically a copy of Europe’s CE testing, ensuring you get a solid product. It’s just important to steer clear of expired GOST filters or anything from the 80s and 90s. These older filters can contain chromium or asbestos, both of which can be seriously hazardous.
More on that in the Filters to Avoid section below.
Some newer mask filters (like those used with the M50) use a proprietary thread, meaning they’ll only work with a specific gas mask. This can provide some key advantages, but it can also limit your choice of filters—at a higher cost than civilian-ready CBRN masks and filters.
Key things to remember about mask filters
Gas masks & filters require at least 17% ambient oxygen levels (19.5% if in accordance with NIOSH) to function, any less requires a self-contained breathing apparatus (SCBA).
The expected concentration of harmful substances in the air, with regard to the period of maximum possible use, should be 1,000 ppm (0.1% volume) for a Class 1 filter; 5,000 ppm (0.5% of volume) for a Class 2 filter; 10,000 ppm (1% of volume) for a Class 3 filter.
If a gas mask filter is used against radioactive substances, mercury or other highly toxic substances, low-boiling organic substances, tear-producing and irritating substances, dangerous microorganisms, NOx or carbon monoxide, it cannot be reused!
Always use a filter with the P3 or P3D filter element against solid and liquid particles, micro-organisms, viruses, smoke, etc.
The maximum useful life of a filter against mercury vapors is legislatively defined by European standards as 50 hours.
Mask filters cannot be cleaned so do not apply pressurized air or water.
As you can already see, there’s no shortage of choices when it comes to picking your gas mask and filter. If you feel overwhelmed, it can be helpful to take a step back and ask what you really need from your gas mask and filter setup. Will you use your gas mask filter on the job?
As mentioned above, canister mask filters offer versatile and reliable protection from hundreds of contaminants, toxins and particles. But these filters are still limited by practical concerns like size, weight and being porous enough for you to comfortably breathe through them.
That’s why individual filters are classified and coded according to a strict system, informing users of the specific types of toxins and compounds each filter can protect against.
|Color||Mask type||Application||Class||Gas Concentration||Standard|
|A||Organic gases & Vapours-boiling point > 65°C||1
|A||Organic gases & Vapours-boiling point > 65°C||1
|B||Inorganic gases and Vapours (not CO), i.e chlorine, H2S, HCN,…||1
|K||Ammonia and organic derivatives||1
|AX||Certain organic compounds with boiling point <65°C - of low boiling substances groups 1&2||gr.1: 100ml/m3 max 40'
gr.1: 100ml/m3 max 20'
gr.2: 1000ml/m3 max 60'
gr.2 5000 ml/m3 max 20'
|NO (+P3)||Nitrogen oxides e.g NO, NO2, Nox||Maximum allowed time of use: 20min||EN141|
|Hg (+P3)||Mercury vapours||Maximum allowed time of use: 50 hrs||EN141|
|CO*C||Carbon monoxide||Local guidelines||DIN 3181*|
|Reactor P3||Radioactive iodine||Local guidelines||DIN 3181*|
You don’t necessarily have to memorize these classifications, but it’s important to keep them in mind when purchasing mask filters.
And beyond the basic classifications, there are a few deeper points to consider…
First is the level of particulate-filtering efficiency. This is a crucial consideration. After all, it’s not just about the contaminants in case of a disaster—there’s also going to be a great deal of dust and airborne debris. These particles can gradually accumulate inside the filter itself, reducing efficiency and increasing the chances you’ll be exposed.
Particle filter levels are currently defined by the EN143 standard to protect users against airborne dust, particles and liquid/solid aerosols. P1 level filters are less efficient, designed to stop at least 80% of airborne particles. P2 filters are designed to stop 94% of airborne particles, and P3 filters offer high efficiency, cutting off at least 99.95% of all airborne contaminants (all at 95 L/min airflow).
Particulate filtration is key to surviving many CBRN threats, which is why most modern CBRN filters offer P3 protection.
Another major factor to consider is the “reactor” classification. As mentioned above, this classification indicates the filter can prevent the intrusion of radioactive iodine often associated with nuclear fallout or post-meltdown exposure. True CBRN filters should almost always have this designation.
Filters may be labeled as either NBC filters (nuclear, biological, chemical) or CBRN filters (chemical, biological, radiological, nuclear). The former is generally considered an outdated term from the Cold War. Some of the most common NBC filters on the market today are old Israeli civilian filters which you’re best off avoiding.
In recent years, NBC filters evolved into CBRN to provide protection from radiological threats like dirty bombs, so you’re best off going for CBRN filters when possible.
Of course, a filter’s classification is only as good as the agency that certifies it—and the standards to which it’s certified.
As mentioned above, the National Institute for Occupational Safety & Health (NIOSH) is a key certification body for American gas masks and filters. NIOSH certification can be prohibitively expensive for smaller companies though, so it typically comes at a premium in terms of cost to you, the consumer.
It’s important to note that NIOSH CBRN certification is given to the gas mask and filter as a unit. So switching to a different filter or a newer gas mask may in some cases be a step away from the NIOSH standard.
And that’s the key with NIOSH; it’s an optional certification unless your gas mask is part of your occupational equipment. You can get a great non-NIOSH gas mask and filter.
Europe’s “CE” is an equally strict standard. The difference is that while non-NIOSH masks can be sold in the US, non-CE masks cannot be sold anywhere in the European Union.
As we’ve covered above, GOST is a Russian standard that closely mirrors CE. GOST also has its own threading standard, so if you are considering GOST-approved filters, make sure they’re compatible with your gas mask.
But what’s the right filter for your needs?
If so, and you’re in the private sector, you’ll likely need a more expensive NIOSH-approved setup (more on that in a moment). State and federal jobs aren’t regulated by NIOSH standards, which gives you more options. Instead, if you’re just trying to prepare for the worst, you can get a reliable NATO standard gas mask and filters for a lower price. Preparing for specific use cases can make your purchases more effective.
But first and foremost, you need to know what it is that you’re purchasing. So let’s take a look at how filters are classified and defined.
Top 4 Mask Filters in 2020
While your individual needs may vary, there are still just a handful of filters that are perfect choices for most buyers, whether civilian or professional, as they cover the widest array of threats.
No gas mask filter can do it all, of course, but these top choices come as close as anything out there. They’re each best in class, proven performers with stellar reviews from consumers and experts alike—so you can buy any of these popular filters with confidence.
And, of course, we know which filter takes the top spot…
Awesome 20-year shelf life
Wide range of protective filtering
Level P3 particle filtering
Vacuum-wrapped for easy storage
It may sound biased, but we take pride in what we do.
MIRA Safety’s filters are the culmination of decades of specialized expertise and manufacturing, creating some of the very best mask filters that Europe has to offer.
Each filter comes individually packaged in its own vacuum-sealed pouch, with clearly-labeled expiration dates and comprehensive protection from a wide variety of airborne compounds.
These filters come with an unmatched 20-year shelf life that can make storage and logistics incredibly easy.
Certified according to some of the strictest European standards, our NBC-77 SOF filters take much of the guesswork and research out of buying mask filters by giving you an obvious first choice for most practical uses.
But every respirator filter has its limitations…
For the NBC-77 SOF, the initial price is higher than other filters. Of course, that pays off in the long run, with a shelf life up to four times longer than many filters.
Combining the best value with some of the best protection and storage-ready packaging, these are easily the best all-around filters to suit the vast majority of buyers. If you don’t read another word, buy some NBC-77 SOF filters for yourself and your family immediately.
Turns your gas mask into a smoke escape respirator
Offers full-spectrum CBRN protection
Ideal protection for home fires & wildfires
Functional in low oxygen environments
13.5-year shelf life
No other gas mask filter demonstrates the flexibility of the platform quite like the VK-450. In a matter of seconds, the VK-450 can transform a standard gas mask into a fully functional smoke gas mask.
Utilizing special media and a high-grade particle filter, the VK-450 is able to retain a wide range of CBRN protection while adding practical protection from smoke, carbon monoxide and airborne particulates.
That added functionality can move your expensive gas mask from the closet to the bedside—transforming it into a potentially life-saving tool in case of smoke exposure. If you’re stocking up on filters, the VK-450 seems like an obvious buy.
The downsides are limited but noticeable.
First, the filter lacks a reactor certification. That means no protection from radioactive iodine in case of nuclear fallout. Assuming you’ve got another filter that’s reactor-certified for full CBRN exposure (like the NBC-77 SOF) then that’s not much of an issue.
But every respirator filter has its limitations…
Likewise with the filter’s higher price. Since you’re only likely to need one or two of these filters, the higher price tag is easier to reconcile. They’re also slightly larger than most filters, which is a minimal inconvenience.
Lightweight polymer housing
7.5-year shelf life
When it comes to buying mask filters, our first and most important piece of advice is to “buy as many as you can comfortably afford,” and the DOTPro 320 is easily the most affordable in filter on the market today.
It’s got great features, Level 3 particulate filtering and stats that match top filters in by the numbers quality. But it also combines a 7.5-year shelf life with a price that beats the competition by about 20%. As a result, the DOTPro 320 is just an easier purchase to make. When you’re buying 10, 20, 30 filters or more, those savings really start to add up.
And it’s important to reiterate that you’re not really sacrificing all that much in terms of protection with the DOTPro 320. There’s no reactor element, to be sure, and it’s not NIOSH approved. But aside from those omissions you’re getting the same quality and peace of mind you’d get from a filter like the NBC-77 SOF at about half the price.
When it comes to budget-friendly mask filters, look no further than the DOTPro 320 for maximum value.
Expensive and impossible to find
The biggest innovation with the U.S. military’s new Avon M50 is to split the standard single filter into two smaller filters. This allows each filter to sit closer to the face, with dual ports to reduce breathing resistance and a compact form factor that allows for easy maneuvering and rifle handling.
Of course, there are a few downsides. First, the shelf life is limited at 5 years. Second, they only last 24 hours at best due to limited filter capacity. And third, they’re practically unavailable in any reliable form to civilian and non-military buyers. While you might find an M50 gas mask or filters online here and there, you won’t be buying them from a reliable dealer, so you shouldn’t trust your life to them.
Nonetheless, the M50 is a tremendous innovation that deserves some credit.
Filter Storage & Shelf Life
The very best gas mask filter is, of course, the one you never need to use.
But if the need arises, you want to be absolutely certain you can count on your gear—which is why we’re going to take a moment to cover storage, shelf life and logistics in general.
It really is key to focus on logistics when purchasing, storing and maintaining mask filters. You’re going to want between 7-20 filters for each member of your family or group, and the filters having an average shelf life of 5-10 years. Successfully managing and storing that amount of sensitive equipment can require some clever thinking.
Take, for example, our MIRA Safety CBRN NBC-77 SOF Gas Mask Filter. This filter sells at a substantially higher cost than a lot of the competition, so a price-minded buyer might steer clear of it. But if you’re focusing on logistics, you’ll notice that the NBC-77 SOF filter lasts a whopping 20 years on the shelf—four times the effective lifespan of most filters. That kind of feature can massively simplify your logistics and maximize value, so it’s important to take the right approach.
When it comes to storage, a general rule of thumb is to store your gas mask filters like you would store ammunition or anything else you consider valuable. So, keep filters away from temperature extremes and sunlight, and store them at less than 80% humidity.
Some CBRN filters come pre-packaged in a vacuum sealed bag, minimizing the need for handling and the risk of moisture. It goes without saying that filters should be kept in these bags, and indeed, you might want to consider bagging your own filters if you have a vacuum sealing machine at home (just be careful not to put too much pressure on the housing).
Once your filters are properly stored, you’re good to go for years.
Just monitor environmental conditions, and track any new purchases/additions so you can keep an eye on expiration dates. Modern NATO filters will have expiration dates clearly printed out the outside of the canister, so you can keep track of shelf life as time goes by.
It hopefully goes without saying that you should NOT try to renew your filters by blasting them with compressed air or attempting to wash them. Instead, safely dispose of the filter once it’s expired and replace it as soon as feasible.
Filters to Avoid
As you’ve already discovered, it’s important to find the right gas mask filter. But it’s even more important to steer clear of the wrong gas masks filters…
It all starts when governments buy filters in bulk. They stockpile millions, preparing for a catastrophe that hopefully never comes. When the gas mask filters ultimately expire, a contractor is hired to dispose of them safely and effectively.
Instead, these often useless and sometimes dangerous filters don’t make it to the landfill. They show up on eBay, and are purchased by unwitting consumers.
This has become a very real problem in countries like Russia, Israel and the Czech Republic.
This is a catch-all for any filter that’s improperly labeled, lacks a legible expiration date or is in any other way suspicious. If you’re not confident that you know exactly what the filter is for and when it was made, it’s best not to trust it with your life.
That includes any filter that comes with an outdated gas mask like any of the following:
GP-5 gas mask
Czech M10 gas mask
Canadian C-4 protective gas mask
Serbian M1 gas mask
M17 gas mask
If it’s a matter of translation or identifying a foreign filter, you may find clues among online forums, but be careful to double-check and confirm anything you read.
Finding Good Filters Is Getting Easier
In the past, when there was less of a market for gas masks and filters, it was common to see low-quality surplus online or at gun shows.
Fortunately, it’s getting easier to avoid these types of filters as the market is becoming more and more sophisticated. If it’s feasible for you and your budget, it’s honestly best to avoid all but the very best gas mask filters.
We’re talking about the very air you will breathe in the event of a major disaster. If and when your life is at stake, you’re not going to care whether you saved a few extra bucks on a gas mask filter, so make sure to buy something that gives you peace of mind. Especially when some premium filters last for up to 20 years on the shelf.
Buy once. Cry once. And avoid cheap surplus gas masks filters like the plague.
Buying and storing the right gas masks filters for your personal needs is a potentially life-saving decision that only takes a few minutes.
As you’ve discovered so far today, there are a great many factors that determine what each filter is useful for, how much it costs and how long it lasts. It might seem overwhelming at first, but for the most part, your needs (and your choices) are going to be pretty straightforward.
Gas Mask Filter FAQs
Here are some final FAQs that you might find helpful when choosing a gas mask:
Gas masks filters combine a layer of mechanical filtering with chemical filtering—separating different particles, bacteria and airborne contaminants through processes like adsorption, where toxins adhere to elements inside the canister filter. Space inside the filter is limited and these filtering mechanisms are complicated/delicate, so filters are often specialized and priced based on how sophisticated the internal elements are.
NOTE: Gas masks and gas masks filters ONLY protect your respiratory system from airborne contaminants. If you’re not wearing a hazmat suit that’s properly sealed with ChemTape, gloves and boots, then your body could still be exposed to potentially dangerous elements.
They generally last 12-24 hours, but they can last far less time if you’re in highly contaminated areas. Filters essentially last until they’re too clogged, damaged or soiled, but they’re also limited by the concentration of certain airborne contaminants so environmental factors play a huge role.
Ideally, you’ll want to minimize exposure and use the mask as little as humanly possible in the event of an NBC event, so one hopes to never have to find out how long a filter lasts. Nonetheless, it’s crucial to keep multiple filters around in case you have to make multiple excursions or endure several hours/days of exposure.
Filter use time depends on a few factors, including atmospheric conditions, type of contaminant, concentration and breathing rate. Please review the technical data of the filter you're interested in for more info. Generally speaking, we recommend having at least one filter per eight hours of use. You will know it's time to swap the filter when breathing becomes labored or you smell something inside of the mask.
Because they’ve been tested and approved by regulating bodies like NIOSH (a part of the Centers for Disease Control) or similar regulatory bodies in the European Union. Each is a gold standard when it comes to respiratory/gas mask testing, and they’ll have records on hand so you can double-check any claims made by a manufacturer.
How many can you comfortably afford? Best practices dictate having a week’s supply on hand for each person who needs a mask. For a family of four that means about 30 filters. Having additional filters on hand never hurts either, especially when they provide different kinds and levels of protection like the VK-450 smoke filter. At the same time, you could reasonably get started with as few as five DOTPro320 filters for a single person without breaking the bank.
Some will be marked reusable, which can be especially useful for NIOSH-approved work filters. It’s important to realize that whatever the filter is removing from the air is still inside the filter, though, so if it’s exposed to CBRN contaminants including radioactive fallout, you should dispose of it in accordance with local regulations.
Gas mask filters can contain a variety of chemicals and compounds that might not be okay to dispose of in your home’s garbage can. Consult your local waste management authority for best practices when it’s time to dispose of old filters.
It’s possible but not recommended because adding an adapter creates an extra potential point of failure to your equipment.