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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. |
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. |
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. |
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. |
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.
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