Gas Masks are essential for plenty of different professions, keeping your lungs clear from toxic chemicals on the job, free of smoke and debris in the unfortunate case of a house fire, and in general for living a longer, healthier life outside these dangerous situations.

With every gas mask, there is a filter that fits it. It is crucial to wear the correct size filter with a proper mask. This way, you are protected from inhaling toxic gasses. Without a filter, your mask is pointless.

There are multiple different kinds of filters for different substances and airborne hazards, but it’s best to first look into what exactly a gas mask filter is.

What is a Gas Mask Filter?

gas mask filter

Gas masks are filtered masks you wear to protect your lungs and throat from breathing in dangerous chemicals that could harm you. A gas mask filter is an insert that goes into the gas mask. It can essentially alter the function of the mask depending on the type of filter.

The air you breathe through the mask passes through the filter first, cleaning and filtering out the toxicity and allowing you to go about safely. Depending on the filter, you can be breathing in and around CBRN, or chemical, biological, radiological, and nuclear substances, and still feel safe.


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How Long Does a Gas Mask Filter Last?

It’s vital to know how long your filter lasts, especially with the dangers that can come up over an old or overused filter that no longer does its job. There are a few things to consider when deciphering how long a filter can last.

Shelf Life

As for shelf life, it’s typical that filters last up to five years unopened, but more advanced brands can offer ones up to twenty years unused. It wouldn’t be wise to use a gas mask filter if it’s been sitting around for a long time, not knowing whether it will be sufficient enough to work.


When it comes to a mask in actual use, it depends on the chemicals you are filtering or not filtering. With toxic chemicals, a filter is most likely only going to last a one-time use, nothing longer than about eight hours. There are specific filters created for such chemicals, and they last longer, but not by too much.

Clean Air

Lastly, even in scenarios where you are unsure if the air is fresh, you should not be using a filter for over twenty-four hours. If you are already looking to buy a mask to be safe, you don’t want to risk your mask failing.

How Do You Select the Proper Gas Mask Filter?

How to choose the proper gas mask filter

There are plenty of reasons in which you could need a gas mask, whether it’s for your job or you just want to have the means to be safe in any scenario. Filters all do the same thing, keeping out substances and particles toxic to us, but what is it they keep out? 

Some filters are designed specifically for different substances. There are filters for gasses, smoke, carbon monoxide, biological hazards, nuclear hazards, and many more dangerous things floating around in our Earth’s air supply. 

Knowing which filter to get is simple. Whatever it is you need it for, there is most likely a filter for it, so research and compare. Luckily, we’ve put together a list of the top five 40mm filters for gas masks. All filters are from MIRA Safety, a brand with reliable gas masks to help you decide which is best for you. 

First, you need to understand what MIRA Safety is and what they can provide to you so you can be safe.

What is MIRA Safety?

Mira Safety

MIRA Safety’s brand is described in its name. Its utmost focus is on safety, providing customers with gas masks, hazmat suits, chemical, biological, radiological, and nuclear equipment kits, and gas mask filters. 

MIRA provides cutting-edge technology to all their equipment. Their self-defense products are used for a ton of military operations, which gives them an extra seal of trust. They create each protective equipment with practicality and safety in mind.

Mira gas mask filters
Mira Safety 40mm Filters

Focusing on the gas mask filters, MIRA Safety provides several different 40mm filters that provide specific protection to whatever it is you need. From CBRN, to a lesser version of NBC, and TIC filtration protection, to simple smoke filters, MIRA Safety offers masks to keep your lungs safe from all of it.

So, whether it is a common airborne gas or a hazardous and toxic chemical, there are options for you to choose from that will keep your lungs clear.

The Top Five 40mm Filters From MIRA Safety Gas Masks

Here are the best MIRA Safety 40 mm Gas Masks for you, all good for different reasons geared towards what you are looking for. 

Best For Chemicals: NBC-77 SOF CBRN Gas Mask Filter

mira ncb-77

The technology on the NBC-77 SOF CBRN Gas Mask Filter is what sets it apart from the others on the list as the best for chemicals. It can filter toxic substances, such as chemical, biological, radiological, and nuclear. This gas mask filter has military-spec technology. This means that it holds a level of technology used by military troops. It’s the real deal.

This filter is best if you work in an occupation that surrounds you with the deadliest of airborne chemicals. It is created for this specific reason, to clean air as such.


  • 20 Year Shelf Life
  • Military-Spec Filtration


  • Best For Only Severe Chemicals

Best For Smoke: VK-450 Smoke/Carbon Monoxide Filter

filter vk 450

The VK-450 Smoke/Carbon Monoxide Filter is the best filter on this list for smoke hazards because of its enhanced filter. It can also protect from carbon monoxide, making it one of the more commonly purchased filters on our list. 

Being exposed to smoke and carbon monoxide is much more likely than nuclear, biological, and chemical substances, but this filter can protect you from all.

With a thirteen and a half year shelf life, this filter is perfect to keep around the house in case of a fire, wildfire, or unexpected carbon monoxide leak. 

MIRA Safety also expresses how this filter paired with a mask is a better alternative to smoke hoods, which can fail in the case of a wildfire.


  • Useful for Fire and NBC
  • Filters Up to as Little as 19.5% Oxygen


  • High Demand

Best For Common Threats: DotPro 320 40mm Gas Mask Filter

The DotPro 320 40mm Gas Mask Filter is the best for common threats because it is the least likely on our list to withstand toxic substances like NBC. Its shelf-life is shorter at seven and a half years and its price is the lowest because of it.

To be clear, this is a decent gas mask filter. Unless you are in a profession that deals with NBC substances, the DotPro 320 is not a bad option for you.  

It cleans all sorts of respiratory threats like Toxic Industrial Chemicals. These chemicals can be hazardous, such as carcinogens and corrosives. 

These chemicals are manufactured, stored, and transported all around the world. But, they aren’t found just lingering around, but if you find yourself in a situation where you’ll need protection from these chemicals, this is the mask for you.


  • Multi-Gas Use
  • Best Entry-Level Filter
  • Lowest Price


  • Smallest Shelf Life

Best For LightWeight: ParticleMax P3 Virus Filter – 6 Pack

particlemax p3 40mm virus filter

ParticleMax P3 Virus Filter in a pack of six is the smallest filter on our list, which is why it is offered in a pack. This doesn’t take away from their shelf life, which reaches up to twenty years. The ParticleMax P3 Virus Filter is made from Ultra-Low Particle Air filtration technology. 

ULPA means these filters can trap even the smallest of viral and bioparticles that threaten to pass through your gas mask.

The size makes it lightweight and more comfortable to wear on your mask. The filter is powerful, but it does not fend off other chemicals, biological, radiological, or nuclear substances. It is meant to keep bacterial threats out of your lungs, not for highly toxic chemicals.


  • High Shelf Life
  • ULPA Filtration Technology
  • Pack of Six


  • No CBRN Protection
  • Higher Price

Best For Long-Term: P-CAN Police Gas Mask Filter

p-can police gas mask filter

P-CAN Police Gas Mask Filter is another filter that is self-explanatory from its name. It is best used as a form of riot gear, protecting you from breathing in hazardous gas, police gas in particular. 

This filter is hydrophobic, which is a feature that can give you close to twelve hours of safety. This keeps you protected from gasses, even in any form of precipitation, due to the activated carbon that is three times other filters.

The P-CAN Police Gas Mask Filter is designed for the workforce’s protection and used by CBRN specialists and military personnel, so they are certainly top of the line to protect you from inhaling gasses for a long time.


  • Hydrophobic Coating
  • Twelve Hour Protection


  • For Specific Use


It ultimately comes down to what kind of gas mask filter you are looking for, but of all the filters above, there is one that stands out as the absolute best one for several reasons. Those reasons happen to revolve around the fact that this filter incorporates all of them and more.


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Best Overall: VK-450 Smoke/Carbon Monoxide Filter

The overall best option out of the gas mask filters above is the VK-450 Smoke/Carbon Monoxide Filter

It is the most versatile gas mask filter, protecting you from breathing in chemical, biological, radiological, and nuclear, as well as smoke from fires and carbon monoxide.

filter vk 450

Whether you need it for a dangerous job or you find yourself in a position where there are toxic chemicals in the air, it will come in handy.

However, the special part of this gas mask filter is its ability to filter smoke and carbon monoxide. This makes it the best because it can become a great purchase for everyone, not just people who work with toxic chemicals. 

It’s a gas mask filter that can save your life, or a family member’s life, from a fire, wildfire, or carbon monoxide leak. It is the one filter on this list that often sells out, coming in high demand for its complex abilities. 

If you’re looking for a filter that can do it all, the VK-450 Smoke/Carbon Monoxide Filter is the one for you.

Written by Abdo

Abdo is a Zoopy writer who loves spending his free time outdoors, camping, and enjoying the peace that nature brings. He also enjoys fixing things - he's particularly good with electronics. His favorite movie is I Am Legend, and he's fascinated by survival gear and safety.

2 comments on “Best 40mm Filters For Gas Mask”

  1. It’s assuring that as pointed out here in this expose, SOME “filters” are made here in the U.S.A. I recently purchased a Respirator and was shocked and then incredulous that the filters included were TESTED and INSPECTED in CHINA. China has recently been exposed for contaminating, poisoning PCR home test Kits. In the past CHINA has been caught, exposed poisoning our TOOTHPASTE, Dog Food, Children’s Toys[The paint] and even drywall that was used in construction back east. So I surely wont rely on something like a 40 mm gas mask filter made in China. You’ve named ONE of your filter choices that are made here. Where are the others made? You’ve mentioned here? It’s acceptable for me to buy 40mm filters made outside of the U.S. like Europe for example. Do you have information related to my Search for 40 mm filtering options that are not Made in China? Great article. Thank You.

    1. Some filters from this article are made in Czech Republic and some are exclusively made for Mira by Sorbent JSC, a company from Russia.

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