What is the top three or so culprits of formaldehyde off gas in a new construction home? Carpet near the top?
Thanks
Plywood, fiberboard, oriented strand board, and other manufactured materials may contain formaldehyde.
carpet isn’t much of a problem?
It depends on the carpet. There are a quite a few that don’t off-gas formaldehyde at all, but it’s not a default. You have to shop carefully.
Per the Canadian department of Environmental and Workplace Health, and the US Environmental Protection Agency, carpet isn’t a source of formaldehyde in the home.
Sheet materials such as plywood, oriented-strand board and fiberboard are the number one source, followed by tobacco smoke and exhaust from vehicles and poorly-vented fireplaces and wood stoves.
For their part, the carpeting industry says there’s no formaldehyde in carpet. (PDF) Another PDF says the flooring industry continues to monitor the manufacture of carpet, padding and adhesives to assure the public that there’s no formaldehyde. I don’t have a hard cite, but it looks like the US carpet industry has not used formaldehyde in carpet manufacture since the 1970s. The carpet fibers, however, will absorb and retain contaminants from the air or the subfloor immediately beneath.
Not to say there aren’t other chemicals in carpet, but for the most part, once it’s unrolled and exposed to air, the residual solvents evaporate within a couple of days.
Human respiration and cooking cruciferous veggies?
According to the Consumer Product Safety Commission memorandum and final report from interagency agreement on volatile organic chemical emissions from carpets (CPSC-IAG-90-1256), formaldehyde is present in new carpet off-gas, and it remains present at a low level even after a few days of airing.
As gotpasswords cited, carpet manufacturers maintain that there is no formaldehyde in carpet and hasn’t been since the 1970s, but the science disagrees. The carpet industry is using many of the same tactics that protected the tobacco industry for decades, and it’s mostly working. There are carpets available that are truly formaldehyde-free, but you have to research carefully before you buy.
How can they say there’s not when there is? Do you mean that the manufacturers are lying, or that the formaldehyde is produced by two chemicals combining (thus: they didn’t directly add the 'hyde) or something else entirely?
According to that cite, only one of the four carpets tested had significant emissions of formaldehyde.
From what I understand, it’s produced by two or more chemicals combining, so they didn’t directly add it, but it’s there. It’s also possible that the manufacturers are just lying, but I’ve seen no proof of that.
I would recommend reading Cindy Duehring’s report on carpet and chemicals here. The site is a little out there for my taste, but the article is well-cited, and her findings here and elsewhere on the interaction of chemicals and human health are consistent with what I’ve found from other researchers in this field.
Canadjun:
I make no claim that formaldehyde is present in all carpet, only that it is present in some, despite the carpet industry’s claims to the contrary. In fact, I said as much in the same post, and in an earlier post. The CPSC study supports that.
Fixed that link for you.
What I recall hearing is that it off-gasses from the glue in manufactured wods; so plywood, but mostly particle board - which a lot of kitchen cabinets and trim such as baseboards and such tend to be made of. The first year or so is worst; then it’s pretty much done and the house is reather safe. So good ventilation the first year is a useful plus.
Even hardwood flooring, which is mostly engineered plywood with a veneered surface, is going to produce gases. Look at all the engineered wood in a home, and it’s all bonded together with adhesives that off gas.
OSB, plywood, hardwood flooring, laminate flooring, particle board, non-stain grade woods, such as baseboard and casings (although these are mostly sections glued rather than entire sheets).
Most hardwood flooring is actually hardwood, at least here in western Canada. Engineered hardwood floor, where the hardwood is bonded to a plywood or HDF (fiberboard) substrate for dimensional stability, is moderately expensive in comparison to common hardwood, and less common as a result - it is an upgrade.
Laminate flooring is usually HDF with a shamefully thin polyurethane wear layer and cosmetic layer on top. That is probably what you are thinking of. It is mostly junk, and the quality stuff approaches the price of cheap hardwood anyways.
Fiberboard is a significant concern for indoor air quality. A lot of trim, cabinetry, and doors are made of MDF, however proper painting or coating is supposed to reduce off-gassing to acceptable levels. As well as the sub-floor itself. the ‘web’ of Engineered floor joists is also OSB.
Manufacturers of engineered wood products claim to have reduced Formaldehyde and other harmful compounds, and low emission products are increasingly available. Formaldehyde and other harmful products in the dust from engineered materials is a serious health concern for woodworkers. There are an increasing number of product lines meant to be safer to work with.
This is an old memory, but, FWIW, you can reduce formaldehyde levels in a building, especially a new one, by sealing it up with lots of ammonia inside. I picture closing all windows and doors and vents, turning off the hvac, and pouring big bottles of household ammonia solution into plastic trays in multiple rooms, so it stinks of ammonia in there. Maybe fans indoors to circulate it around, and leave all the closet doors open.
I gathered that this causes some chemical reaction into something other than formaldehyde, something less troublesome, and does so for substances that were not about to offgass in the immediate future. In other words, this isn’t like an airing out, it doesn’t have to wait for the formaldehyde to stick its head out to smack it with a hammer. Rather, it relies on the ability of ammonia to permeate into things.
But I have no cite and don’t know enough chemistry to even guess what is going on. Does anybody know anything about this?
Interesting. Anyone else have info on this?
How much formaldehyde are you talking about here? Formaldehyde is a natural compound that exists at low levels many places.
I suspect the ammonia thing may work through attack of the ammonia molecule on the carbonyl. Whether it goes all the way to the imine or stays at some other intermediate, I don’t know. The process is probably also reversible on a humid day.