For characters with Superman-style "super breath", the amount of air being forcefully exhaled is often vastly greater than is possible to hold in human-sized lungs. However, this poses two major problems that I've never seen addressed in any examples of this superpower, nor could I figure out an answer for:

  1. Even if we somehow assume the respiratory system has enough superhuman strength to put inhaled air under the highest pressure possible without turning said air liquid, how can it even inhale that much air to begin with? Per the physics of respiration, the inhalation process will ultimately stop once pressure equilibrium is achieved between the lungs and the outside atmosphere. So how can one circumvent that?
  2. What of the case where the exhaled air is so great, it couldn't have been possible achieved with the volume of human lungs even at maximum non-liquifying pressure? Is there any way to justify this (quasi-)scientifically, i.e. without involving another superpower (e.g. outright magic) that violates any and all relevant laws of physics?
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    $\begingroup$ A series of biomechanical pumps actively pushing the air in, just as the two sided human heart is a total of 4 chambers, with pairs of chambers arranged in series. $\endgroup$ – Ghedipunk Aug 23 '18 at 22:49
  • $\begingroup$ @Ghedipunk: Shouldn't that go into an answer? Also, I've edited the post to add a second part to the question. $\endgroup$ – MarqFJA87 Aug 23 '18 at 22:51
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    $\begingroup$ I'm putting it there for people to expand on. I'm too lazy to take the time to write proper, insightful answers. $\endgroup$ – Ghedipunk Aug 23 '18 at 22:51
  • $\begingroup$ Check out how a bird's respiratory system works. $\endgroup$ – pojo-guy Aug 24 '18 at 0:00

A totally normal human solution:

The answer here is circular breathing, a common technique employed by wind instrument players, allowing them to hold notes for a very long time.

Here is a very nice example of the technique being perpetrated by a saxophonist. Yes, ladies and gentlemen -- forty seven minutes five and one half seconds of the same note without pausing for a breath. I am certain he could have continued for much longer, but the sound engineers were already threatening murder by about twenty-five minutes in.

Super Breath

Super Duper Girl can very easily blow The Prankster, Emu, Mrs. Slushy, the Irate Haberdasher, and all the rest of the dastardly gang of vile villains and eerie evildoers infesting MetroCity away using this same technique!

The reason why Super Duper Girl uses this technique, as opposed to Hairy Tongue Halitosis's compressed air trick is that she can easily outlast the villain's stinky breath, thus saving thousands of MetroCity's beleaguered citizens from pulling their own noses off their faces in an attempt to stop smelling his pungent mal aire!

Super Duper Villain Compressed Air Technique

Hairy's technique involves starting the process of inhalation normally, by expanding his ribs and diaphragm, to get the air flowing into his lungs. Now, Hairy is a pretty stout fellow, and under normal respiratory conditions, his lungs can hold about 7 or 8 litres of air. But once he breaks out into his trademark neck-thrust/chest-compression stance (looks better in the comix than I can describe here, I assure you!), a kind of rapid peristaltic movement is engaged by super human muscles in his trachea & bronchus. The combination of rapid peristalsis drives litre after litre of air into his body, while the hyper flexion of his chest and core muscles causes all that air to be compressed. He can easily compress about five gallons of air --- 20 litres without breaking a sweat; and with a little more effort, he can compress ten gallons of air --- 40 litres. Of course, the downside is that Hairy has an (untried) maximum volume / maximum compression strength. He could possibly force the air to become liquid, but he will eventually run out of space to store even liquid air!

enter image description here

I can assure you, no normal citizen of MetroCity can withstand anything like twenty litres of Grade A Stinky Air! It's gotten to the point, where all Hairy Tongue Halitosis has to do is show up in a deli or shop and people literally start giving things to him, just hoping he'll go away before he starts breathing on everything!

Super Duper Hero Circular Breathing Technique

On the other hand, Super Duper Girl, takes an entirely different approach. In order to accomplish her super duper skill, she must first puff out her cheecks and purse her lips. She can easily put Dizzy Gillespie to shame:

Those cheeks! That horn!

She then uses Circular Breathing to periodically inhale air through the nose and into her lungs, and periodically exhale air through her mouth; while at the same time, inflating her cheeks & controlling the back of her oral cavity, thus closing it off, so she can continually exhale an uninterrupted flow of air through her mouth, even while breathing in.

Circular Breathing diagramme

There is no downside to Super Duper Girl's power: she can do circular breathing long after Hairy Tongue Halitosis has gasped the last of his super villain breath, and she'll still be blowing strong!


This is a workaround rather than a solution to the exact questions you posed. The workaround is to use throughput: air comes in through the nose and is exhaled through the mouth. It doesn't require the lungs to store it. A peristalsis-like motion in the nasal cavity draws in air towards the back of the mouth; the trachea closes; and the air is "exhaled" through the mouth. (Maybe the Superman-style person inhales a large breath of air into the lungs just to oxygenate his/her body during this "nasal peristalsis" procedure, during which no new air is getting to the lungs.)

  • $\begingroup$ I think I read something like this somewhere. It's called "cyclic breathing", isn't it? $\endgroup$ – MarqFJA87 Aug 23 '18 at 23:27

The answer to your first point is to use a pump (or, even better, a series of pumps). Each pump will allow a pressure differential to develop between the intake (atmosphere for the first pump in the series) and the exhaust (the lungs proper for the last pump in the series). Depending on the technology and materials used, the pressure differential Pexhaust/Pintake can range from 1.02 for 103. The human respiratory system is one half of a peristaltic pump where the intake and the exhaust are combined into one duct, the trachea.

There is no need to worry about the air liquefying as room/body temperature is well above the critical temperatures for both N2 and O2, which are both well below -50 degrees centigrade. I'd worry more about the containment vessel (the lungs and lung cavity) bursting or distorting such that it obstructs other bodily functions. This is also an answer to point 2: if the lungs of your superhuman are strong enough to hold an interior pressure of say 1 million atmosphere to an exterior pressure of 1 atmosphere (100 kPa), then your superhuman can exhale 1 million times the volume of his lungs, see this list. In fact 1 million atmospheres (1011 Pa) is 10 times the pressure at which oxygen solidifiesat room temperature to red oxygen so 1010 Pa is a more likely upper limit.

Another way around point 2 is to combine the nitrogen and oxygen from the inhaled air with other compound using chemical reactions to something else, either solid or liquid. This usually requires some energy. The solid or liquid forms take up a lot less space than the gaseous foms. But please be advised that quite a few compounds involving nitrogen and oxygen (and some carbon and hydrogen) tend to be quite unstable and explosive. This may be a bonus as the exhalation will then be very fast.


Your superheros blow vast volumes via entrained air.

entrained air https://evacuumstore.com/p-26984-dyson-air-multiplier-technology.aspx

This is how the Dyson "air multiplier" works. The device shoots a very fast jet of a small amount of air. Friction between this very fast moving air and adjacent air carries the adjacent air along. This effect multiplies out until the force put into the very small jet of air is adequate to move a large volume of air at reasonable speed.

The supers purse their lips and blow a very fast moving stream of air. This winds up moving a lot of air along - much more than the super could contain in her body.


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