Make me into a human sniffer dog

February 22, 2007 5:15 AM

There's a very faint smell in my bedroom. I can't track down the source. Does anyone have any tips for tracing down the source of odours?

There've been a number of questions on AskMe before on what a smell is or how to get rid of a smell, but this one aside they almost invariably know the source of a smell in advance.

I just can't track my smell down. It's too faint, and I usually only notice it when I'm in bed, but it's not coming from the bed, behind it, or under it. I just can't figure out where it is coming from - it's too faint and not always there.

Surely there must be some way to improve the almost useless human nose and help me sniff out the source?

posted by edd to grab bag (21 comments total)

edd, you're a science nerd, or i wouldn't suggest this: got an RGA?
posted by sergeant sandwich at 5:41 AM on February 22, 2007

My money's on a decomposing mouse in the walls.

If that were the case, I'd say put out a scented candle for a while until the bugs eat it.
posted by mr_book at 5:42 AM on February 22, 2007

If you describe your smell, somebody may think of places you could try sniffing.
posted by flabdablet at 5:43 AM on February 22, 2007

I would check the radiator and carpet.

Also, what kind of pillows do you have? Do you have one of those memory foam things? I have learned that the cheaper memory foam starts to develop an odor after awhile, despite multiple pillowcases.
posted by tastybrains at 5:49 AM on February 22, 2007

If you open the window and air the place thoroughly, then close up again and let the smell acumulate for half an hour or so, you may be able to temporarily establish a more definite smell gradient which could help in detecting the source.
posted by Phanx at 6:05 AM on February 22, 2007

Rent a beagle?
posted by JJ86 at 6:09 AM on February 22, 2007

If the odor is mildew or mold related and you don't have carpet (the first culprit in any odor tracing) you might try painting the walls with a lacquer based primer sealer. In one house I lived in the plasterboard wasn't sealed before painting and the waterbased paint reacted with the board to produce an odor of mildew in a brand new room.
posted by ptm at 6:12 AM on February 22, 2007

The fact that mr_book's answer sounds plausible should answer flabdablet's question. I'll try sniffing nearer the bottom of the walls, and give Phanx's suggestion a go too.

tastybrains: Had a good sniff of the radiator and the bedding, pillows included, so I don't think it's them.

The RGA sounds fun, but hard to get hold of!
posted by edd at 6:29 AM on February 22, 2007

You may laugh, but bringing in a dog would be a good option. A well trained cat could help as well.
posted by pezdacanuck at 7:05 AM on February 22, 2007

This is just shot in the dark, but I have had a couple of instances where a nasty smell similar to a dead mouse was coming from an electrical outlet that went bad and partially melted. Replacing the outlet fixed it. I had to look pretty close to find the culprit, though.
posted by TedW at 7:11 AM on February 22, 2007

Is your bed near a window on the ground floor? There might be a dead animal out there.
posted by DU at 7:29 AM on February 22, 2007

Also try a sniff test on any nearby plumbing, sewer gas getting through a leaking or badly installed trap can come and go. I tore apart the bedroom looking for a mouse before I found it was coming from the sink in the nearby bathroom.
posted by InkaLomax at 8:25 AM on February 22, 2007

The problem I always have in tracing a smell is is accommodation; after I smell a faint smell for a while I can no longer smell it, even though the source is still present. On a couple of occasions I've been able to use a painter's mask to get past that. In your situation, I would try a silicone rubber mask with the most basic activated charcoal cartridges; I'd wear the mask into the room, then take it off and take a couple of big sniffs at a particular location, put it back on, wait for a few moments and move to a new location and repeat. After a few iterations, go back to the location where the smell seemed strongest and do the same thing on a finer grid. This is how I found a kumquat which had rolled far under a piece of heavy furniture and developed a nasty electric blue infestation of mold.
posted by jamjam at 8:26 AM on February 22, 2007 [1 favorite has favorites]

try your sneakers
posted by pinksoftsoap at 9:07 AM on February 22, 2007

The fact that mr_book's answer sounds plausible should answer flabdablet's question. I'll try sniffing nearer the bottom of the walls, and give Phanx's suggestion a go too.

Egads, you could'a just said that it smelled like dead mouse.

Anyway. Seconding the possibililty of plumbing. If the pipes have deteriorated and water is gathering in the walls, it can give off a dead-creature-esque stench. I suppose that water damage from a roof, if permitted to trickle, could produce a similar effect.
posted by desuetude at 10:10 AM on February 22, 2007

No nearby plumbing, a couple of floors up and it's not coming in through the windows.

Still can't find anywhere that the smell seems to be coming from. It's an unpleasant slightly sulphurous smell, but maybe not that of a corpse. Given the lack of anything else to go on, I've got a scented candle in and will hope it fades rather than worsens for now.
posted by edd at 10:18 AM on February 22, 2007

Is there an outside wall? If there is, I recommend removing the switch plate cover from an outlet on the wall. We did that (just to replace the cover) and found a bad leak. We had noticed a smell but couldn't find any moisture or anything else that seemed to be the culprit.
posted by dpx.mfx at 11:11 AM on February 22, 2007

Try to find the smell, then, when your nose tires out, go sniff some coffee beans. No, really. Coffee beans kind of "reset" your nose so that you can go try again. That's why nice perfume shops usually have a little jar of them nearby.
posted by iamkimiam at 12:30 PM on February 22, 2007

Get an incense stick, light it, and probe it around all sides and corners of the "cube" that makes your room. Go around the outlets and windows. Basically anywhere there is a seam.

Look for the smoke to waft, indicating a small draft. See if the draft carries the scent.
posted by Ynoxas at 1:30 PM on February 22, 2007

Do you have incandescent lighting?
posted by flabdablet at 8:21 PM on February 22, 2007

The plastic-degradation described in flabdablets link is the same thing I was describing with electrical outlets above. The same plastic is used in a lot of electrical products so could be the source in a number of ways.
posted by TedW at 10:05 AM on February 25, 2007