Sciencemadness Discussion Board

Removing fishy smell from air - possible?

RogueRose - 15-12-2018 at 11:18

Every time I walk by the new seafood counter at my local grocery store I get very sick to my stomach, the last couple times I almost vomited in the middle of the isle (I was kind of sick at the time, so the smell made it worse). I'm reminded of the smell of some chemicals such as Trimethylamine & methylamine and other amines - it is EXTREMELY unpleasant for many people and it makes others openly gag when they smell it. This effects everything in about a 40-60ft radius (4,000 - 7,500 ft^2!!) which is a large area..

I'm wondering if there is anyway to neutralize this offensive odor and whether activated carbon would be enough and if it isn't is there any other substance that can neutralize the odor, possible with something acidic or basic - in a similar manner that air is dried by passing it through a bed of CaCl2 or something.

I'm not very well versed in what causes the smell, if it is the chemicals evaporating into the air and then just traveling with air, or if there is some other action at work here.

I looked at how the seafood counter is set up and all the food is kept in an enclosed refrigerated display case that is only opened when adding or removing stock - the excess food is kept in a large stand-up refrigerator/freezer - not a walk-in. So it seems that the air from inside the display case is getting mixed with the outside air pretty readily for some reason.

DraconicAcid - 15-12-2018 at 11:31

The smell is amines (given off by the decomposition of amino acids in proteins)- you need something acidic to neutralize it. That's why seafood is usually cooked with lemon juice.

Ubya - 15-12-2018 at 11:33

if it smells that bad it's old fish.
to cover the smell, add acid. adding lemon juice or vinegar removes the "fishy" smell, maybe try breathing through a cloth wet

edit: 2 seconds too late f*ck

[Edited on 15-12-2018 by Ubya]

RogueRose - 15-12-2018 at 12:32

Thanks for the suggestions. I think the problem is bigger than old/bad fish (crab/lobster/etc) I think it is normal when there is a large amount of it even if it is fresh.

I was wondering if there was some kind of filter that could be put into the display case, possibly something in-line with the air cooling system. IDK if AC would remove that smell but I'm guessing something acidic would. Could passing the air through a bed of sodium bisulfate possibly remove the odor, or possibly through a cloth/screen with a bisulfate solution (or even vinegar or citric acid solution)?

Sulaiman - 15-12-2018 at 13:04

A cooker hood filter, recirculating air through inbuilt carbon filter ?
e.g. https://www.ebay.co.uk/itm/SIA-ST60SS-60cm-Visor-Stainless-S...

Unscrupulous traders have been known to use formaldehyde and similar,
if it smells of 'chemicals', or has no flies where others do, then don't buy

Fresh fish has very little smell - refrigeration seems appropriate.

Alternatively, set up a child in business selling lit incense sticks at $/£/Euro 0.1 each
e.g. https://www.ebay.co.uk/itm/Extra-Long-Incense-Joss-Sticks-Sc...

[Edited on 15-12-2018 by Sulaiman]

Nakhimov - 18-12-2018 at 07:54

Fish odor is due primarily to methylamine; the acid reacts with the basic amine to form the conjugate acid of the amine, which has no odor.

Obviously this wouldn't be an issue in situations where you want to be in acidic media but might be a problem for bases. Really, you could just buffer in those cases if your reactions aren't pH sensitive.

unionised - 18-12-2018 at 08:41

The usual solution to the problem would be exhaust ventilation.
Collect the fishy smell and fan it outside.

Another, obvious solution would be not to go to that shop.

Extracting/collecting the amines from such shops?

fusso - 18-12-2018 at 09:35

What about bringing a few grams of solid acids (eg oxalic, tartaric, citric) to the shop (of cos not letting anyone know), stay in the shop for a few hours, wait for the amines to be absorbed into the acid, and see how much amine is collected?

12thealchemist - 18-12-2018 at 09:40

The amount of amine required to give a smell is absolutely minuscule. With a home lab set up, the quantity you would "collect" would be undetectable, unless you have deep pockets and powerful instruments.

DavidJR - 18-12-2018 at 13:54

I actually don't think the smell of (mono-) methylamine is that unpleasant....

unionised - 18-12-2018 at 14:12

Quote: Originally posted by DavidJR  
I actually don't think the smell of (mono-) methylamine is that unpleasant....

I don't think it's that relevant.
Fish use trimethylamine N oxide for regulating osmotic pressure.
When they die it is decomposed to trimethylamine which is the stuff that's troubling the OP.

Tsjerk - 18-12-2018 at 15:50

As said above exhaust ventilation is the way to go. And if it stinks it is rotten. A proper fish retail shouldn't smell bad.

AJKOER - 18-12-2018 at 17:54

Removing fishy smell from air - possible? Answer is yes!

I accidentally prepared a concoction to remove what was believed to be a contaminant on the floor. Curiously, it actually work for a few hours and then the smell returned. The next day I repeated the process on the floor, and observed the same phenomena. Subsequently, a bursting old can of salmon was discovered on a lower shelf.

So yes, it is possible but the actual gas I had generated may be unsafe to inhale (it literally degraded the gaseous compound responsible for the smell).

Sorry that I'm a bit cryptic, but I have at one point commenced a patent right up on the composition.

So removing the smell is one thing, but removing the source, that's perhaps another problem.

Be carefully not to make an unpleasant situation much more dangerous by the introduction of chlorine based compounds!!

[Edited on 19-12-2018 by AJKOER]

unionised - 19-12-2018 at 11:53

Now that's odd.
I was expecting AJKOER to pop up here.
But I was expecting something involving ozone or peroxide and hard UV light- which might actually work here.

If you try that approach, be sure to keep the NOx levels (and thus potentially nitrosamines) under control.

clearly_not_atara - 19-12-2018 at 11:59

As long as we're producing acidic gases I'd guess releasing a small amount of SO2 would kill the fishy smell. It's not the safest gas but there's much worse, certainly better than HCHO or NOx.

Tdep - 19-12-2018 at 18:14

ozone ozone ozone ozone
The problem isn't the chemistry or the chemicals. The problem is the weak homo sapiens with their flimsy, pathetic biological lungs. Fix the biological problem (remove all people ever) and most chemistry gets a lot easier

AJKOER - 20-12-2018 at 05:02

Sorry guys, but the active gaseous compound likely responsible for the chemical eradication of the fishy based odor has not yet been mentioned.

Note, the word 'acidic' is not really accurate, and it was a two step application (a clue).

I have decided not to provide any more responses, even if the right agent is listed, but enjoy speculating if you must.

If in 2 years if I have not patented the method, remind me and I may bore you with the chemistry (yet another clue!).

[Edited on 20-12-2018 by AJKOER]

CuReUS - 20-12-2018 at 05:31

https://allsharktankproducts.com/shark-tank-products-home/pu...

http://naturallygone.co.uk/

AJKOER - 20-12-2018 at 05:50

CuReUS:

Thanks for the marketing research!

Wow, finally products that actually remove/destroy odors, in place of all that over advertised junk that equates to a perfume bath!

However, I am waiting for comments by our resident biochemist(s) on the safety issue (it is hopefully not a perfect product, leaving room for competition!).

BOBardment - 27-12-2018 at 21:06

Gas mask is your friend, forget about the weird looks, this is the new fashion now. ;)
Looking great while breathing fresh fresh filtered air, that's what I call practical.

lordcookies24 - 3-1-2019 at 06:07

I would use acid. Like acetic acid or citric acid.

mayko - 3-1-2019 at 17:41

Quote: Originally posted by Sulaiman  

Unscrupulous traders have been known to use formaldehyde and similar,
if it smells of 'chemicals', or has no flies where others do, then don't buy



then there's this scam, which is less toxic yet somehow more insulting:

https://www.bbc.com/news/world-middle-east-45398254

andy1988 - 4-1-2019 at 11:20

Reminds me of a college prank where a friend put opened tuna cans in his gf's dorm vents... very good prank. I wouldn't be surprised if there is rotting fish underneath heavy equipment or in some crevice and it is never cleaned. After working a year at a college food place... we never cleaned underneath the refrigerated units (too heavy!). I tried but the space was too narrow for a broom. Call health department?

Could be lethal to some apparently? The grandmother must be devastated :(
https://www.bbc.com/news/world-us-canada-46757704

draculic acid69 - 4-1-2019 at 18:35

I always thought that the smell was from an oil in the fish.fish oil really stinks.a mix of fish oil and trimethylamine would be much worse.

[Edited on 5-1-2019 by draculic acid69]

zed - 5-1-2019 at 15:47

Personal sensitivity to odors, varies over time.

Physical health, and psychological status, hold great sway.

When you are unwell, your body looks fer excuses, to Gaaaack up your stomach contents. Odors give it clues. Might be the problem... Puke stuff up. End of problem!

Have you had a lot of solvent exposure lately? Liver acting up?

Nothing like an unhappy liver, to amplify stink induced nausea.