New Carpet Concerns

A colleague of Janet, over at Adventures in Ethics and Science, recently asked ScienceBlogs if certain chemical compounds in new carpeting could increase the risk of allergies for her young child. My father has been working in environmental safety for most of my lifetime. When I first brought my son home, I pestered him endlessly with questions about making my home a safe environment. Usually I was overreacting, but it was always reassuring to have that expert opinion at hand. Unfortunately, not everyone is lucky enough to have a chemist for a father. So, in hopes of reassuring Janet's friend and other mothers moving into a new home, I passed this question along to him:

I have been looking for places to live. The pickings are extremely slim in my price range. I thought I had found something that will work. It is a small guest house behind someone else's palatial house but very private and with a lot of good features. The only bad thing is that it has this overwhelming new carpet smell, which I thought I could live with, given the other good features, especially if I open the windows and let it air out. But, after applying for the place, I looked up some articles on VOC's and new carpet, which I had only vaguely heard of somewhere before. I did not even know what VOC stood for until I did a Medline Search. Anyway, I found two articles about VOC's increasing small children's chances of having asthma and other respiratory problems, and then I found one article that says that Volatile Organic Compounds from new carpet are not a major health risk to humans, so it all seems a little contradictory. I have a one and a half year old son who lives with me. I am worried now about moving into this place with him, but only have looked at article abstracts. I don' have access to the full text without doing an interlibrary loan request.
How would you recommend trying to get to the bottom of this and making a decision about it? It is a fairly common practice for landlords to slap in some new cheap carpet before a new tenant moves in, but I don't want to do something that could be a health risk for my son. (What parent does?)

Here is his response:

Volatile organic carbon molecules ("VOC's") are a class of molecules that use carbon as a building block and are small and light enough to evaporate at room temperature. As you might imagine, that is broad range of compounds; in fact, we live with VOC's all the time. We even generate and release VOC's every time we exhale.

There are VOC's that occur naturally, and VOC's created through industrial processes. Many products used in households such as furniture, carpets, paint, and even clothing release VOC's when new and as they age. Many VOC's are compounds that have detectable odor at very low concentrations while many have no odor no matter how concentrated. What makes evaluation difficult is that odor and toxicity have little or no relationship. There are many very foul smelling things that will not hurt you but odorless things that can make you very sick.

A lot of people have looked at indoor VOC's as a class and attempted to determine what hazards might be associated with them. Most of the studies I have seen found that the typical indoor VOC mix does not cause any measurable or significant harm. Part of this may be due to regulatory and industrial efforts to reduce the overall amount of VOC's emitted by new products. Part of it may be due to increasing regulation of those compounds known to cause measurable harm. In any event, new carpet today releases fewer VOC's overall and far fewer toxic VOC's than did the new carpet of the 1960's.

Do indoor VOC's increase the risk of allergies and asthma? I think that there is not very strong evidence for any substantial increase in risk. There seems to be a much bigger risk associated with extremely fine particulate matter such as that generated by burning diesel fuel or coal. (You may have seen the acronym "PM10" that stands for particulate matter less than ten micrometers in diameter.) There is an increasing amount of evidence that those particulates can cause respiratory system allergies and reactions. While such PM10 particulates are typically composed largely of carbon, and they float around for a long time because of their small size, they are not considered "volatile" because they remain as solid particulate and not evaporated gases. I have not seen studies that say that home products typically release PM10 carbon particles the way that they can release VOC's. It could be that a child would be safer indoors with new carpet than outdoors breathing in particulates from truck exhaust.

However, there have been a myriad of theories as to why the rates of allergies and asthma have been increasing. Some think that it may be that our environments have been too clean, some studies have found that not having pets around as an infant increases the chances, others that some homes that have cockroach infestations and increase a child's chances of getting these conditions. There is yet a great deal yet to be learned about auto-immune diseases in general, but I would not personally worry about any hazards associated VOC's from new carpet. There seem to be many other things that are more strongly associated with such diseases.

Having dealt with severe allergies, asthma, and allergic eczema for much of my life, I would be thrilled if they could pin down some specific causes. The research community seems to be making great progress, but they are not quite there yet. As far as new carpet goes, I think it feels great to walk on it in bare feet. Take your shoes off and stay a while. You might want to use a vacuum cleaner that is equipped with a HEPA filter to capture the dust-borne allergens that carpets tend to collect over time.

Linn Havelick, Certified Industrial Hygienist

Arvada, Colorado

Thanks, Dad!

Image of carpet fiber magnified 10x via Microscope Camera Images.