RESPIRATORS AND CLEAN AIR - How Do Respirators Allow You To Breathe Clean Air In A Contaminated Environment - A respirator is a device you can use to protect yourself from inhaling harmful or even poisonous substances. Any device that can do that could be theoretically referred to as a respirator. Respirators come in different shapes and sizes and are appropriate for different settings. You don’t want to use a gas mask designed for stopping dust in a place filled with harmful gases, because it would be absolutely useless and would potentially put your life in danger. Activated charcoal is another very common choice for filters in respirators, as each particle or granule of carbon offers a large surface area where pollutant particles can get trapped and adsorbed. Such filters are quite effective at filtering out acidic gases, such as chlorine, and particles like sediment and volatile organic compounds. Activated carbon filtering is even used in cigarette filters! The other and relatively more sophisticated way of being able to breathe in a contaminated setting is by using a respirator whose filters contain a substance that could react with the ‘bad’ chemical and neutralize it. For instance, a respirator with calcium oxide will bind with carbon dioxide present in the air and turn it into a different product. This way, all the harmful carbon dioxide will be removed and the user will be able to breathe in the contaminated environment.

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Respirators And Clean Air

How Do Respirators Allow You To Breathe Clean Air In A Contaminated Environment  

By Ashish

Have you watched the popular American TV show Breaking Bad?

The lead characters of the show are often shown working in chemistry labs, wearing respirators that basically cover their entire face.

The lead characters of the show Breaking Bad always wore respirators while working in their lab.

There are many movies and TV shows that depict people donning respirators before entering a “contaminated” area.

In fact, respirators are not so uncommon, even in real life: firefighters wear a special type of respirator when entering sites that still have a lot of smoke and soot.

Chemists wear them in the laboratory and even elite security forces wear respirators before going into the “target area”, if they are expecting chemical threats.

I must admit, the first time I saw people putting on respirators in a contaminated environment, I couldn’t figure out how those little mask-like items worked.

I mean, I understood that the respirators could cover their nose and face and protect them from external injuries, but they still had to breathe in the same contaminated environment, right?

As in, the air they breathed still contained those impurities and harmful gases, so how did the respirators protect them from all that harmful smoke?

It’s very simply, actually, but first things first…

What is a respirator?

Different kinds of respirators.

A respirator is a device you can use to protect yourself from inhaling harmful or even poisonous substances (e.g., dangerous gases that contain ‘bad’ chemicals). Any device that can do that could be theoretically referred to as a respirator.

Respirators come in different shapes and sizes and are appropriate for different settings.

The second part of that sentence is the really important part.

You don’t want to use a gas mask designed for stopping dust in a place filled with harmful gases, because it would be absolutely useless and would potentially put your life in danger.

How do respirators work?

There are two ways to make contaminated air breathable:

1) physically filtering the air, and

2) reacting the contaminated air with a substance that removes or neutralizes the harmful chemicals within it.

A Polish MUA Gas Mask. Used from the 1970’s to the 1980’s
and was replaced by the Polish MP-4 gas mask.

There’s also a third way, wherein you could carry your own oxygen supply when entering a contaminated zone, but we’re only going to discuss techniques to filter air using respirators.

Consider dusty air, for example.

The gas mask that would be required to breathe in such a setting would contain a paper filter that could physically prevent dust particles from entering through the mask (to gain access to the nose or mouth of the wearer).

Self-Contained Breathing Apparatus. These types of respirators —
called a Self-Contained Breathing Apparatus (SCBA) — are usually worn by firefighters
on a mission. Such respirators use their own air tank to supply clean air,
so the wearer doesn’t have to worry about filters at all. 

Paper filters have very small holes that let only oxygen pass through and block all unwanted particles (e.g., dust, smoke, soot particles etc.).

It’s important to note that such a basic mask will be absolutely useless in the presence of toxic gases.

Activated charcoal is another very common choice for filters in respirators, as each particle or granule of carbon offers a large surface area where pollutant particles can get trapped and adsorbed.

Imagine filtering rocks out of sand… if you have a filter with pores that are big enough to let sand pass through, but are small enough to block rocks, filtering the rocks out of the sand would be easy, right?

That’s exactly what these types of filters do — they let oxygen molecules pass through and block bigger pollutant particles.

German soldiers with gas masks, 1915.
In the rudimentary gas masks used in the first world war, it was found
that wood charcoal was a good absorbent of poison gases.

Such filters are quite effective at filtering out acidic gases, such as chlorine, and particles like sediment and volatile organic compounds. Activated carbon filtering is even used in cigarette filters!

The other and relatively more sophisticated way of being able to breathe in a contaminated setting is by using a respirator whose filters contain a substance that could react with the ‘bad’ chemical (present in the contaminated air) and neutralize it.

For instance, a respirator with calcium oxide will bind with carbon dioxide (i.e., the pollutant) present in the air and turn it into a different product.

This way, all the harmful carbon dioxide will be removed and the user will be able to breathe in the contaminated environment.

Then again, this sort of respirator would be absolutely useless against chlorine or mustard gas.

That’s why it’s VERY IMPORTANT to check what kind of contamination setting a particular respirator will be effective in, as entering a ‘bad air’ zone wearing the wrong kind of respirator is tantamount to not wearing one at all!

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spends a lot of time watching movies, and an awful lot more time discussing them. He likes Harry Potter and the Avengers, and obsesses over how thoroughly Science dictates every aspect of life… in this universe, at least.

ScienceABC.com was launched with the sole objective of finding and sharing fun and interesting science facts. We believe that Science is a fascinating and valuable area of study for people of all ages, and we’re not alone! This website is curated by a team of professionals who are passionate about Science. Our greatest hope is that the fun we have curating this content is the same for everyone who reads it.

https://www.scienceabc.com/eyeopeners/how-do-respirators-allow-you-to-breathe-clean-air-in-a-contaminated-environment.html

ACTIVATED CARBON - Activated Charcoal and How It Works - Activated charcoal is carbon that has been treated with oxygen. The treatment results in highly porous charcoal. These tiny holes give the charcoal a surface area of 300-2,000 m2/g, allowing liquids or gases to pass through the charcoal and interact with the exposed carbon. The carbon adsorbs a wide range of impurities and contaminants, including chlorine, odors, and pigments. Other substances, like sodium, fluoride, and nitrates, are not as attracted to the carbon and are not filtered out. Since adsorption works by chemically binding the impurities to the carbon, the active sites in the charcoal eventually become filled. Activated charcoal filters become less effective with use and have to be recharged or replaced.

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Activated Carbon

Activated Charcoal and How It Works

by Anne Marie Helmenstine, Ph.D. 

Activated charcoal (also known as activated carbon) consists of small, black beads or a solid black porous sponge.

It is used in water filters, medicines that selectively remove toxins, and chemical purification processes.

Activated charcoal is carbon that has been treated with oxygen. The treatment results in highly porous charcoal.

These tiny holes give the charcoal a surface area of 300-2,000 m²/g, allowing liquids or gases to pass through the charcoal and interact with the exposed carbon.

The carbon adsorbs a wide range of impurities and contaminants, including chlorine, odors, and pigments.

Other substances, like sodium, fluoride, and nitrates, are not as attracted to the carbon and are not filtered out.

Since adsorption works by chemically binding the impurities to the carbon, the active sites in the charcoal eventually become filled.

Activated charcoal filters become less effective with use and have to be recharged or replaced.

What Activated Charcoal Will and Won't Filter

The most common everyday use of activated charcoal is to filter water.

It improves water clarity, diminishes unpleasant odors, and removes chlorine.

It's not effective for removing certain toxic organic compounds, significant levels of metals, fluoride, or pathogens.

Despite persistent urban legend, activated charcoal only weakly adsorbs alcohol and it not an effective means of removal.

It will filter:

·               Chlorine

·               Chloramine

·               Tannins

·               Phenol

·              Some drugs

·              Hydrogen sulfide and some other volatile compounds that cause odors

·             Small amounts of metals, such as iron, mercury, and chelated copper

It won't remove:

·              Ammonia

·              Nitrates

·              Nitrites

·              Fluoride

·              Sodium and most other cations

·              Significant amounts of heavy metals, iron, or  copper

·              Significant amounts of hydrocarbons or petroleum distillates

·             Bacteria, protozoa, viruses, and other microorganisms

Activated Charcoal Effectiveness

Several factors influence the effectiveness of activated charcoal. The pore size and distribution vary depending on the source of the carbon and the manufacturing process.

Large organic molecules are absorbed better than smaller ones. Adsorption tends to increase as pH and temperature decrease.

Contaminants are also removed more effectively if they are in contact with the activated charcoal for a longer time, so flow rate through the charcoal affects filtration.

Activated Charcoal De-Adsorption

Some people worry that activated charcoal will de-adsorb when the pores become full.

While the contaminants on a full filter aren't released back into the gas or water, used activated charcoal is not effective for further filtration.

It is true that some compounds associated with certain types of activated charcoal may leach into the water. For example, some charcoal used in an aquarium might start to release phosphates into the water over time. Phosphate-free products are available.

Recharging Activated Charcoal

Whether or not you can or should recharge activated charcoal depends on its purpose.

It's possible to extend the life of an activated charcoal sponge by cutting or sanding off the outer surface to expose the interior, which might not have fully lost its ability to filter media.

Also, you can heat activated charcoal beads to 200 C for 30 minutes. This will degrade the organic matter in the charcoal, which can then be rinsed away, but it won't remove heavy metals.

For this reason, it's generally best to just replace the charcoal.

You can't always heat a soft material that has been coated with activated charcoal because it might melt or release toxic chemicals of its own, basically contaminating the liquid or gas you want to purify.

The bottom line here is that you possibly could extend the life of activated charcoal for an aquarium, but it's inadvisable to try to recharge a filter used for drinking water.

Anne Marie Helmenstine, Ph.D.

Introduction

Ph.D. in biomedical sciences from the University of Tennessee at Knoxville - Oak Ridge National Laboratory.

Science educator with experience teaching chemistry, biology, astronomy, and physics at the high school, college, and graduate levels.

ThoughtCo and About Education chemistry expert since 2001.

Widely-published graphic artist, responsible for printable periodic tables and other illustrations used in science.

Experience

Anne Helmenstine, Ph.D. has covered chemistry for ThoughtCo and About Education since 2001, and other sciences since 2013. She taught chemistry, biology, astronomy, and physics at the high school, college, and graduate levels. She has worked as a research scientist and also abstracting and indexing diverse scientific literature for the Department of Energy.

In addition to her work as a science writer, Dr. Helmenstine currently serves as a scientific consultant, specializing in problems requiring an interdisciplinary approach. Previously, she worked as a research scientist and college professor. 

Education

Dr. Helmenstine holds a Ph.D. in biomedical sciences from the University of Tennessee at Knoxville and a B.A. in physics and mathematics with a minor in chemistry from Hastings College. In her doctoral work, Dr. Helmenstine developed ultra-sensitive chemical detection and medical diagnostic tests.

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https://www.thoughtco.com/how-does-activated-charcoal-work-604294