Semi-Volatile Organic Compounds are in everything from your dust bunnies to your dental floss.
That's Bill Walsh of the Healthy Building Network, speaking at the North American Passive House Network conference in New York City. Most designers and concerned consumers these days are aware of Volatile Organic Compounds (VOCs), the chemicals that give you that new car or shower curtain smell, the formaldehyde released from particle boards. These decline with time, which is why I have often recommended vintage furniture that has already outgassed anything that is going to be emitted. Concerned designers and consumers have many VOC-free options these days,
Bill Walsh, however, says that the next big challenges in indoor air quality are Semi-Volatile Organic Compounds (SVOCs). These do not outgas and are not affected by ventilation; they are more like particles of chemicals. So when I told you to buy vintage furniture that didn't outgas VOCs, I forgot to mention that the brominated flame retardants might crumble out of the vintage urethane foam cushions or the Per- and polyfluoroalkyl substances (PFAS) or stain repellants that the vintage fabric was treated with.PFAS (and PFCs or per- and poly- flourinated chemicals) are called "forever chemicals" because they are so persistent in the environment. They are still found in stain repellants, non-stick pans, and cleaning products. PFCs are what make your Gore-Tex jackets so waterproof and breathable (they are phasing them out) and your Glide dental floss so slippery. (I can't believe people use this stuff!)
According to the EPA,
The most-studied PFAS chemicals are PFOA and PFOS. Studies indicate that PFOA and PFOS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals. Both chemicals have caused tumors in animals. The most consistent findings are increased cholesterol levels among exposed populations, with more limited findings related to:
- low infant birth weights,
- effects on the immune system,
- cancer (for PFOA), and
- thyroid hormone disruption(for PFOS).
There has been a lot of progress in reducing exposure to SVOCs. Phthalates are being eliminated from vinyl products, and flame retardants are no longer required in all furniture or in foam that is used below grade. But they are still all around us, and are often required by building codes (such as flame retardants in foams and plastics). Bill Walsh explains how they stick around and get into our bodies, and how difficult they are to measure:
The “semi-volatility” of an SVOC means that a product will also release microscopic particles that attach to indoor surfaces and dust. These can be ingested by mouth directly from the air and food, as well as absorbed through the skin. They can persist a long time in the built environment, even after the source has been removed. SVOCs are more difficult to measure than VOCs because they are released slowly from their sources, over long periods of time, through routine wear and tear, and at variable rates that are not well understood. Exposures to SVOCs through air, food, and touch will vary significantly depending upon a multitude of lifestyle factors. Methods of estimating SVOC exposures in the built environment “remain limited.” Exposures are typically estimated by measuring SVOC concentrations in household dust.
Bill Walsh notes that none of the building certifications, from LEED to WELL to the Living Building Challenge, do a really good job of dealing with SVOCs. "Product and building certifications must do more to reward and incentivise leadership on SVOC elimination as a foundation of healthy building practice, for example by making such credits prerequisites to certification."
So really, designers and consumers are largely on their own. A good place to start is the HomeFree overview of products.
It's also really important to deal with the SVOCs in your home. They have an affinity to household dust, and TreeHugger Melissa described a dust action plan to wrangle the dust bunnies, including:
- Vacuum frequently with a machine with a HEPA (high efficiency particulate air) filter. These vacuums are more efficient at trapping small particles and can remove contaminants and other allergens that a regular vacuum would recirculate into the air. Change the filter often, and don’t forget to vacuum the stuffed furniture (get under those couch cushions).
- Pay special attention to places where little kids crawl, sit and play. They live closest to the floor and are exposed to those toxic dust bunnies.
- Equip a forced-air heating or cooling system with high-quality filters and change them frequently.
Read them all in her post: Your dust bunnies are likely toxic.
VOCs are problematic, but at least they can be ventilated away and the ones in building products go away over time. SVOCs are another story; they are bioaccumulative and build up in our bodies over time. We should be taking them a lot more seriously.