Mystery dust.

February 17, 2009 7:29 AM

A mysterious gray film/residue is appearing on all of the plastic in my apartment. What is going on?

It's on the ice cube trays, the tupperware, the coffee maker, my printer, the dishwasher, etc. It's all over a plastic grocery bag that has been lying in the living room for only two days (close-up). My roommate and I have never seen anything like it before. Is it mutant dust of some kind?

If anyone can identify this substance, we would love to confirm that it is not going to kill us.

posted by prefpara to home & garden (21 comments total)

It it toner? I'm taking a stab from the closeup that it's a laser printer. Loose toner would stick to the plastics more than other things because they more effectively hold a static charge and it's winter. The printer looks a little worse than the other stuff. Can you open it up and check if you've got a toner leak?
posted by range at 7:33 AM on February 17

It's an inkjet printer, actually. But I've seen toner residue before, and that's a solid guess! However, the residue also appears on the plastic trash bag in the bathroom, so it doesn't seem likely that it's coming from just one object in the apartment (I think).
posted by prefpara at 7:35 AM on February 17

Looks like light soot to me. How's your furnace? Do you have a fireplace? Does your heating system use air vents?
posted by Cat Pie Hurts at 7:52 AM on February 17

Soot would be my guess too. What does the residue feel like? Is it dry or greasy? What happens when you try to rub it off with a cloth? Does it come off cleanly with a dry cloth or does it smudge? Does it wipe cleanly with a wet cloth?
posted by ssg at 8:05 AM on February 17

You are probably running a humidifier. The residue is the minerals in the water that are thrown into the air by the humidifier, as well as dust in the air being dissolved by the little water droplets and then redeposited onto the plastic stuff.
posted by gjc at 8:07 AM on February 17

I am not home now, but will run the "cloth rub" test when I get back. Meanwhile, I can confirm that I am not running a humidifier, do not have a fireplace, and know of no heating vents in the apartment. We have a gas stove, if that helps.
posted by prefpara at 8:13 AM on February 17

You could also try to go "sweeping" with a light colored piece of plastic to attract the stuff. It would useful to see if there's more of it, say, near a heater vent. I'm betting it's everywhere and you're noticing it only where it can collect (b/c of static) and be visible (light background color).

In the meantime, it might be a good idea to presume it's everywhere and start ventilating the place -- there are a few itsy bitsy particulates that are genuinely dangerous (like carbon fiber dust, though I have a hard time imagining how that gets into your house) to breathe and others, like soot, that are probably fine in the short term but over time give you all those lovely coal-miner diseases you read about in school.

Actually, before ventilating it would be good to figure out if the stuff is heavier than air or not -- shine a flashlight at it so you can see airborne particles, shake a little up, and see if it eventually settles. If it stays aloft (carbon fiber would do this), you need to do wet cleanup to keep the dust down.
posted by range at 8:13 AM on February 17

How close do you live to an airport?
posted by MasonDixon at 8:18 AM on February 17

Looks like the standard city grime that adheres to polymers during dry, static-y weather. Did a nearby building test its diesel generator recently? A humidifier might help.

(gjc, not sure a humidifier would put water-based minerals in the air. Most, if not all, would form that chalky crud that lurks in water equipment in hard water areas.)
posted by scruss at 8:26 AM on February 17

Do you have a big place? have you been cooking a lot of greasy food lately? Windows open? Live near major traffic areas?
posted by Max Power at 8:27 AM on February 17

Do you have an ionizer or air purifier, by any chance? I imagine you would have said when you answered about the humidifier, but I had a white plastic shelf turn sooty black in about 3 months after I set an (old-school static-based) air purifier on it. It would come off, but pretty much only with a solvent of some kind.
posted by Lyn Never at 8:35 AM on February 17

We live on the island of Manhattan. There are no air purifiers or ionizers in the place. We've been cooking a lot of oatmeal, and sometimes I like to fry chicken in butter, stuff like that. Our windows have been closed all winter except for a few days last week (but the mystery smudges predate that). I've been living in NYC for years without seeing anything like this, though my last apartment was in a newer building.
posted by prefpara at 8:41 AM on February 17

A humidifier actually can put weird powder into the air and all over everything. From my understanding of it, the cool-mist type spits tiny particles of water into the air, complete with mineral solutes. It's not like it's boiling/evaporating the water, which would leave the minerals behind. As the water floats through your home, the tiny droplets really do evaporate, leaving the minerals to settle all over everything. My humidifier does this all winter long, but it leaves a white powder on everything, not gray.
posted by vytae at 8:41 AM on February 17

We have this exact same phenomenon at my house (hope it's not dangerous to breath because it's been like this for years and years here). We have electric heaters so it's not happening because of heating combustion, but I do burn a lot of candles. Do you burn candles, prefpara? Maybe it's soot from candle-burning?
posted by amyms at 9:34 AM on February 17 [1 favorite]

Just wanted to add to my comment, we do have a gas-burning floor furnace but it hasn't been used this year, and we have a gas-burning water heater. What kind of furnace and water-heating does your building have, prefpara?
posted by amyms at 9:37 AM on February 17

Does your apartment have forced-air heating? (As opposed to radiators) If some maintenance work was done recently on the heating system, it might have dislodged some crud that was previously sitting peacefully inside the ducts. The crud in this case would be the particulates that are ever-present in Manhattan air, which gradually settle out in quiet nooks and crannies.

This sort of happened in my house after we worked on the heating ducts, except instead of a visible residue, something that made me sneeze my head off was released into the air. We only tinkered with a small section of ducting, but it sure knocked a bunch of stuff loose. Ugh.
posted by Quietgal at 9:38 AM on February 17

I would try and find out if other people in the building have the same thing happening to them. This way you could find out if it has to do with the building or just in your apartment.
posted by Mastercheddaar at 10:17 AM on February 17

I thought the same thing as amyms. We burn a lot of scented candles, and the cheaper they are (i.e. non-food grade paraffin), the faster they cover everything in soot.
posted by peep at 10:39 AM on February 17

I will occasionally burn a tea light in one of these Ikea lanterns. I don't know how the heat is set up in the building. I did notice when I got home that the gray stuff is mostly on the part of the bathroom trash can that faces the window, which tends to confirm the theory that this stuff is making its way into the apartment from outside, and soot sounds like a very likely guess. If it is soot, why won't it come off of the ice cube trays, no matter how hard I scrub or how many times I run them through the dishwasher?

Anyway, thanks so much for your time and mental energy, MeFi grime detectives. I will proceed on the assumption that it is harmless soot or city pollution (and not toxic chemical x).
posted by prefpara at 1:45 PM on February 17

(gjc, not sure a humidifier would put water-based minerals in the air. Most, if not all, would form that chalky crud that lurks in water equipment in hard water areas.)

I speak from experience- this happens when I run the humidifier, and it looks exactly like the photos posted.
posted by gjc at 4:45 PM on February 17

Mystery solved. It's soot. I just learned that our boiler has been acting crazy, setting fires, and spitting out tons of soot. So I am not so worried about random toxic dust, but slightly more worried about burning up in a fire.

Thanks for your guesses and advice, metafilter!
posted by prefpara at 10:07 PM on February 19