The Ultimate Buyer's Guide for Purchasing Gas Purification Equipment

We can survive three weeks without food, three days without water, but only three minutes without breathable air.

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That's why gas masks can be a lifesaver in disasters, terrorist attacks, or nuclear meltdowns. But without the right filter, even the best gas mask is useless.

Fortunately, modern 40mm gas mask filters are specialized to protect you from hundreds of toxins and airborne contaminants-ranging from chemical to biological, radiological, and even nuclear-all while fitting the same gas mask.

For example— a single type of filter can protect you from all of the contamination from a nuclear meltdown for up to 24 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 impregnating 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 sometimes even experienced buyers. That mistake can cost you time and money…or something even more critical.

So, we will look at everything you need to know about gas mask filters: from their practical function and specifications to the logistics of storing them and, should the need arise, putting them to 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

• 01

  Gas Mask Filters 101

• 02

  Filter Classification

• 03

  Filter Certification

• 04

  Top 3 Gas Mask Filters of

• 05

  Filter Storage & Shelf Life

• 06

  Filters to Avoid

• 07

  Conclusion

• 08

  Gas Mask Filter FAQ

Gas Mask Filters 101

The history of gas masks and how gas mask 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.

On the other hand, modern gas mask filters are indeed a technological marvel.

Due to the precise nature of filter construction and the mechanics involved, there are a few key classes of filters you'll notice immediately:

To produce a modern gas mask filter takes remarkable skill and expertise. Fortunately, it couldn't be any easier to put one to use.

Gas mask filters are easy to carry, use and store, with a shelf life that can stretch into decades. Depending on the specific filter, they can provide up to 40 hours of practical protection from airborne contaminants and toxins.

Any worthwhile gas mask filter will have these details in the included documentation. This can make logistics straightforward, as seen in the Storage & Shelf Life section below.

Many filters have the same round shape and size that you probably already know, which makes finding compatible cartridges easier. 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 +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 gas 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 EN148-1), making these filters a popular and readily available choice for law enforcement, private military contractors, and civilians.

There are plenty of choices when picking your mask and filter. If you feel overwhelmed, step back and ask what you need from your gas mask and filter setup. Will you use your gas mask filter on the job?

Filter Classification

As mentioned above, canister gas 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 and weight and are porous enough to comfortably breathe through them.

That's why individual filters are classified and coded according to a strict system, informing users of the types of toxins and compounds each filter can protect against.

You don't necessarily have to memorize these classifications, but it's necessary to keep them in mind when purchasing gas mask filters.

And beyond the primary classifications, there are a few more profound 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 will also be a great deal of dust and airborne debris. These particles can gradually accumulate inside the filter itself, reducing efficiency and increasing your chances of exposure.

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 block 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 critical to surviving many CBRN threats, which is why most current 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. Genuine 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.

Gas Mask Filter Certifications

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 certification body for American masks and filters. However, NIOSH certification can be prohibitively expensive for smaller companies, so it typically comes at a premium cost to the consumer.

It's important to note that NIOSH CBRN certification is given to the mask and filter as a unit. So switching to a different filter or a newer mask may sometimes be a step away from the NIOSH standard.

Goto RICH to know more.

And that's the key with NIOSH; it's an optional certification unless your mask is part of your occupational equipment. You can get a great non-NIOSH mask and filter.

Top 3 Best Gas Mask Filters of

While your individual needs may vary, just a few filters are perfect for most civilian or professional buyers as they cover the most comprehensive array of threats.

No gas mask filter can do it all, 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 confidently buy any of these popular filters.

And, of course, we know which filter takes the top spot…

Filter Storage & Shelf Life

The best gas mask filter is, of course, the one you never need to use.

But if the need arises, you want to be sure you can count on your gear—so we'll take a moment to cover the storage, shelf life, and logistics.

It is vital to focus on logistics when purchasing, storing, and maintaining gas mask filters. You will want between 7-20 filters for each family member or group, and the filters have 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 Military 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 20 years on the shelf—four times the effective lifespan of most filters. That feature can massively simplify your logistics and maximize value, so taking the right approach is essential.

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 should 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 on the outside of the canister, so you can keep track of shelf life as time passes.

It goes without saying that you should NOT 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, finding the right gas mask filter is crucial. But it's even more critical to avoid the wrong gas mask 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 landfills. The filters show up on eBay and are purchased by unwitting consumers.

This has become a real problem in Russia, Israel, and the Czech Republic.

Conclusion

Buying and storing suitable gas mask 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 may initially seem overwhelming, but your needs (and choices) will be pretty straightforward.

Best Gas Mask Filter FAQs

Portable room air purifiers are designed to filter the air in a single room. They’re separate from whole-house air purifier systems and air filters, which are integrated into a home’s heating, ventilating, and air conditioning system and designed to clean the air in the entire house.

Think of a room air purifier as a supplemental unit, like a space heater in the context of a whole-house heating system, explains Misha Kollontai, who oversees testing of air purifiers at Consumer Reports. While your house might feel sufficiently warm, you might have a particularly drafty room with old, poorly sealed windows; placing a space heater there would make the room more comfortable. Similarly, he says, "a whole-house system will work at filtering all the air that passes through it via the HVAC system. But if you’re sitting next to a fireplace in the living room for extended periods of time, a room air purifier there may not be a bad idea." A room air purifier may be worth it too, say, in a bedroom, if you sleep with your pet.

Different air purifiers work using a range of technologies. A few are helpful. Others are ineffective, or even potentially harmful to your health.

Mechanical filters: These purifiers use fans to force air through a dense web of fine fibers that trap particles. Filters with very fine mesh are called HEPA filters. While they work on microscopic particles, they can also remove larger particles (including dust, pollen, and some mold spores) when they’re suspended in the air. (Some filters are labeled “HEPA-type” or “HEPA-like”—these have not been certified to meet the requirements of a true HEPA filter but may still perform adequately in our tests.) Mechanical filters don’t help with gases or odors. And they can be expensive to maintain. Mechanical filters need to be replaced every six to 12 months; they can cost upward of $200 per filter but typically cost no more than $80.

Activated carbon filters: Unlike mechanical filters, these filters use activated carbon to capture certain types of gases, including some odor-causing molecules. But they’re not particularly effective against formaldehyde, ammonia, or nitrogen oxide. Because activated carbon filters don’t combat particles, many air purifiers will have both an activated carbon filter and a mechanical filter. Activated carbon filters get saturated faster than mechanical filters, though, and require replacement more frequently—every three months, as opposed to every six to 12 months for mechanical filters. Make sure to budget for replacements accordingly: Activated carbon filters usually cost up to $50 each. 

Ozone generators: These machines produce ozone, a molecule that can react with certain pollutants to alter their chemical composition. This can result in dangerous indoor air quality, and CR does not recommend these types of air purifiers. Makers of ozone generators often claim that the devices emit safe levels of ozone, but in the past, our tests found that even at low settings, some ozone generators quickly exceeded the Food and Drug Administration’s limit of 0.05 parts per million for medical devices. Plus, studies reviewed by the EPA have shown that low levels of ozone—the chief ingredient of smog—don’t effectively destroy indoor pollutants. Research also shows that ozone has been linked to decreased lung function and increased risks of throat irritation, coughing, chest pain, and lung tissue inflammation. Ozone exposure might also worsen asthma, emphysema, and bronchitis.

Electrostatic precipitators and ionizers: In these electronic models, particles in the air become charged so that they stick—magnet-like—to plates on the machine or to nearby surfaces. CR doesn’t typically test electronic air purifiers nor recommend them because they can produce ozone.

Ultraviolet germicidal irradiation (UVGI): Some manufacturers claim that their air purifiers kill airborne viruses, bacteria, and fungal spores with UV lamps. But they might miss certain bacteria and mold spores that are resistant to UV radiation. To work, the UV light must be powerful enough and the exposure must last long enough—minutes to hours, rather than the few seconds typical of most UVGI air purifiers—to be effective. CR does not test UVGI technology, though some mechanical air purifiers we test may have the added function.

Photocatalytic oxidation (PCO): Some air purifiers use ultraviolet radiation and a photocatalyst, such as titanium dioxide, to produce hydroxyl radicals that oxidize gaseous pollutants. Depending on the pollutant, this reaction can generate harmful byproducts, such as ozone, formaldehyde, nitrogen dioxide, and carbon monoxide. CR does not currently test air purifiers with PCO technology. There have been few field investigations exploring the effectiveness of PCO air purifiers, but one laboratory study, conducted by researchers at Syracuse University in New York, reported that the devices did not effectively remove any of the VOCs typically found in indoor air. 

Photoelectrochemical oxidation (PECO): This variant of PCO emerged in from the manufacturer Molekule. The Molekule Air purifier did not score well in our tests for dust, smoke, and pollen removal. Since then we’ve also tested the more expensive Molekule Air Pro, which performed better at removing contaminants on its highest setting but did not impress in CR’s other air-purifier test categories, nor did it rate well in our CR member survey. 

To see how well these machines clean the air, we inject smoke and dust into a sealed chamber and use a particle counter to measure the change in air particle concentration in the room as the test model runs for 15 minutes. 

We test using particles as small as 0.1 micrometer and up to 1 micrometer, a range that includes dust mite allergens, cat allergens, smog, smoke, and atmospheric dust. We don’t measure for particles larger than 1 micrometer, such as pollen, because any air purifier that scores well in our tests should also be able to handle larger airborne particles.

Because most air purifiers have several speed settings, we test for dust and smoke removal both on the highest speed and at a lower speed that runs at a noise level no louder than 50 decibels. We also measure noise levels at every speed setting that a machine has. And because air purifiers must be running at all hours to be effective, we calculate annual operating costs, which include filter replacements and energy use to run the machine 24 hours a day for an entire year.

Owner satisfaction and reliability ratings are also included in a model’s Overall Score. These ratings are based on Consumer Reports’ Summer Survey of 8,377 air purifiers purchased between and . The very best models in our tests effectively sanitize the air of dust, smoke, and pollen, and receive high marks for predicted reliability and owner satisfaction. 

CR recommends more than three dozen models in our air purifier ratings, and most use a HEPA filter; a vast majority also have carbon filters to help assist in the removal of odors. These models meet Consumer Reports’ criteria for safety, performance, value, and reliability. For more information, read our article on the best and worst air purifiers of the year.

Cost of replacement filters: As a general rule, you should replace filters (or clean those that can be vacuumed) every six to 12 months if they are pleated and every three months for activated carbon filters. Most of the units we test have an indicator light that lets you know when to change (or clean) the filter. The costs of filters vary widely: In our tests of large air purifiers, they range from $20 to more than $200. Filters with odor-removing carbon can cost as much as $50. 

Clear Air Delivery Rate (CADR): This value is provided by air purifiers tested by the Association of Home Appliance Manufacturers. Many air purifiers have undergone AHAM’s voluntary certification program, which provides room size guidelines along with the CADR on its AHAM Verifide seal. The CADR reflects, in cubic feet per minute, the volume of clean air that an air purifier produces on its highest speed setting. For example, a purifier with a CADR of 250 for dust particles reduces particle levels of dust to the same concentration that would be achieved by adding 250 cubic feet of clean air each minute. The higher the CADR, the faster and more efficient the air purifier is. Room air purifiers with HEPA filters often achieve the highest CADR. There are different CADR ratings for removing tobacco smoke, dust, and pollen. Focus on the CADR for your main pollutant of concern. For instance, if you live with a smoker, choose an air purifier that has a high CADR for tobacco smoke. 

Energy Star certification: Air purifiers must run around the clock to be effective, so you should factor in the energy cost when you shop. Energy Star certified purifiers are 40 percent more energy-efficient than standard models. 

Room size: If an air purifier has an AHAM Verifide seal, you can trust that the unit can handle the suggested room size listed on the seal. Be wary about manufacturers’ claims, though. We have tested many air purifiers that are not suitable for their claimed room sizes. You can check our ratings to see what room-size range we suggest for each model based on our test results. Also, consider sizing up: Most models suitable for large rooms (350 square feet and larger) can also work well for smaller rooms at lower speeds. Lower speeds tend to be quieter—which is nice for when you’re watching TV or sleeping.

Noise: Judge an air purifier not just by how well it performs but also by how well you’ll be able to live with it. Because these machines should always be running, ideally they should also be quiet. (For reference, a noise rating around 50 decibels is roughly equal to the hum of a refrigerator.) You may be able to find a model’s decibel levels on its packaging or website listing before you buy it. Or check our air purifier ratings; we rate models on noise levels at both high- and low-speed settings.

Clean or replace filters regularly. An air purifier can’t run efficiently if it has a dirty filter. Typically, you should replace filters (or clean those that can be vacuumed) every six to 12 months for pleated filters and every three months for activated carbon filters.

Place it wisely. If you have just one unit, put it in the room where you spend the most time. For most people, that’s the bedroom. (Some units can be heavy and clunky to move around, so if you want an air purifier in multiple rooms, you may want to buy a unit for each room.) Make sure to place the air purifier in a spot where nothing can obstruct airflow—away from curtains, for instance.

Adjust the speed. To avoid noise disruptions, we suggest running the unit on its high-speed setting when you’re not in the room and turning it down to low when you’re nearby. Or buy an air purifier certified for a larger area so that you can run it on a low speed and still have it work effectively. 

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