Earth with a high concentration of atmospheric ethyl alcohol

Question

Suppose you have an Earth-like planet which (for reasons completely unrelated to the question) spontaneously generates and maintains an atmosphere with an atmospheric ethyl alcohol concentration of 1%. This cannot be altered no matter what processed is performed. For instance, an attempt to diffuse the alcohol out of the air en masse will simply result in more ethyl alcohol being produce. For simplicity's sake, let us also assume that the elements used to construct the alcohol are being drawn from the planet's crust. (This gives rise to an idea that this is a result of a unique plant generating this atmosphere using a corrupted version of photosynthesis, but that's the what this question is seeking to explore.)

The question is as follows: Given this planet of 1% atmospheric ethyl alcohol, what effect would this have on the human population who lived there? After all, gas exchange in the lungs is accomplished through diffusion, and human blood does not (under normal circumstances) have ethyl alcohol produced naturally within it.

I'm primarily seeking an answer from an anatomical standpoint, but sociological approaches will also be appreciated. And, if you have the time for it, the original version of this question was going to use 14% ethyl alcohol concentration, but I quickly came to the assumption that would likely kill the human race, so if you can justify or disprove that, I would appreciate it.

Answer 1

Even at 1% in air, the ethanol would still kill humans.

Ethanol will absorb into the body through lungs and mucous membranes via exposure to vapor just as it would through ingestion, and over time the concentration in the blood would reach an equilibrium with the vapor in the lungs.

That concentration would most likely be lethal. A blood alcohol level of 0.4 g/L (appr. 0.04% abv) or slightly higher is sufficient to kill about half of humans, and the blood concentration due to 1% ethanol vapor in air would surely exceed this figure.

Beyond this, people would become grossly non-functional (too drunk to walk, never mind operate equipment, do work that requires paying attention, etc.) fairly quickly, and well before lethality, if breathing this atmosphere directly. There would be the hazard, then, of stepping out for what should only take two minutes, without protection, being delayed slightly, and winding up too drunk to save yourself (similar to the effects of hypoxia if a pressurized aircraft at altitude slowly loses cabin pressure).

The only option, given it's impossible (short of bare rock terraforming) to remove the source of this alcohol, would be for all humans who will breathe this air for more than a few minutes to breather through organic vapor filters (not particulate masks like we've been wearing for the pandemic, but actual gas masks like the ones the English carried around during the Blitz). Babies and children don't do well with this kind of filtration (due to the effort needed to draw air through the cartridges), and even for an adult wearing such a mask for prolonged periods is tiring.

Therefore, your humans would be confined to filtered-air spaces most of the time -- and while less stressful than living in pressure suits on an airless world, this would push your world far down the scale of desirability as a colony, if there are other worlds with more "normal" atmospheres.

If you still had 14% ethanol with similar partial pressure of oxygen to what we have on Earth (appr. 33 kPa), your atmosphere would require only a little compression to be ignitable/explosive, like the mixture in the cylinders of an internal combustion engine running on E85 or higher fuel.

Answer 2

The energy density of ethanol is about 25 MJ/kg. Air density is 1.2 kg/m3. 1% in air would be 0.21 MJ/kg. Air heat capacity 718 J/kg. Which means this is enough to heat the air from 10 C to about 300 C. It is half the explosion hazard lower limit.

This means that all of the burn and heat processes are changed a lot. All of the wildfires will go extreme. All of the burning equipment will need to be recalibrated.

This also will make the 'free energy' devices possible. Catalytic heaters and recuperator burners will work with no added fuel! Once this will become known, assuming there is someone alive, these devices will replace all other energy generation machinery.

Answer 3

1% ethyl alcohol in the atmosphere would be ten times the legal exposure limit https://www.nj.gov/health/eoh/rtkweb/documents/fs/0844.pdf At this level there would be serious health effects within minutes or hours and probably death within hours or days. Oxygen in the atmosphere would also oxidise the ethyl alcohol to acetaldehyde and then to acetic acid. The exposure limit for acetic acid is only 10ppm. So it would not end well.