Emerging research on SVOCs and indoor air quality

The building industry has made great strides in reducing Volatile Organic Compound (VOC) emissions in the built environment by incorporating many low-VOC certifications into standards such as LEED and the WELL Building Standard™️ (WELL™️). In some cases, the health benefits have extended beyond the built environment, with important environmental justice and social equity impacts. For example, as formaldehyde has been removed from particleboard1 and fiberglass insulation2, emissions from manufacturing facilities to local communities have declined dramatically. The next generation of indoor air quality challenges for the building industry requires an expanded focus to address a class of chemicals known as Semi-Volatile Organic Compounds (SVOCs). Below we discuss emerging research into SVOCs found in the built environment, including several chemicals associated with endocrine disruption that are widely used in building products: plasticizers, stain repellents, and flame retardants.3

SVOCs differ from VOCs in ways that have a critical effect on efforts to prevent human exposure. To simplify, the “volatility” of VOCs means that they are typically emitted by “off gassing” to the air at room temperature, dissipating over time as the molecules break down or air is exchanged. Concentrations of VOCs tend to be highest in, and released at higher levels from, new products. Exposure occurs primarily through inhalation.

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.4 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.”5 Exposures are typically estimated by measuring SVOC concentrations in household dust.

Like their VOC counterparts, SVOCs can have a wide range of human health impacts, including endocrine disruption. Some of the most scrutinized endocrine disrupting chemicals in the built environment are SVOCs.3 Some of the most common examples include:

Plasticizers known as orthophthalates have been widely used in flexible vinyl products such as flooring and wall coverings. Phthalate exposures in humans has been linked to changes in sex hormone levels, altered development of genitals, and low sperm count and quality. Phthalates have also been linked with obesity, reduced female fertility, preterm birth and low birthweight, a worsening of allergy and asthma symptoms, and altered toddler behavior.6

Stain repellents known as PFAS (per- and polyfluoroalkyl substances) are a workhorse class of chemicals that stop liquids from absorbing where you don’t want them to – red wine on your carpet (Scotchgard), water on your rain jacket (Gore-Tex), even eggs on your frying pan (Teflon). They virtually never break down in the environment and are found in people, fish, and wildlife all over the world, with no realistic solution in sight. Dr. Joseph Allen, Director of the Healthy Buildings Program at the Harvard University School of Public Health dubbed them “forever chemicals,” “a group of toxic chemicals that may be associated with testicular cancer, kidney cancer, high cholesterol and suppression of vaccine effectiveness in children.”7 Over 200 scientists from 38 countries have called upon product manufacturers to cease using PFAS.8

Flame retardant chemicals (known as halogenated chemicals) that have been used in furniture, carpet, insulation and wire and cabling are also SVOCs associated with health impacts related to endocrine disruption.9 Like PFAS many of these chemicals last virtually forever once released, and have been documented in humans and the environment around the world.10

Because these chemicals are difficult to measure and control, the most prudent and effective way to reduce human exposure from the built environment is to eliminate their use in building products to the maximum extent possible. Important strides have been made. Safer alternative plasticizers exist.11 In 2015 the Home Depot led the retail market in requiring orthophthalate-free vinyl flooring from all of its suppliers.12 Carpet manufacturers are moving away from the use of PFAS-based stain repellent coatings. One manufacturer, Interface, has phased out PFAS entirely. Recent changes in California regulations mean that halogenated flame retardants are no longer required in furniture (2015), or for insulation used below grade (2019).

The Living Building Challenge lists many SVOCs as “red list” chemicals, and their use can be indirectly discouraged, though they are not prohibited, by LEED and WELL standards. Challenges remain, however. None of these toxic chemicals are prohibited from use in building products by law, and some flame retardants are effectively required by building codes. As was the case with VOCs, increasing the incentives to avoid SVOCs in building standards scoring criteria holds the potential to accelerate product innovation and reduce exposures in the built environment. The advances to date in addressing plasticizers, flame retardants and stain repellants make clear that the potential for dramatically reducing these health hazards in the built environment is within reach.

*Further challenges remain with VOCs as well. As of 2013, not all VOCs known to be in building products are covered by product certifications and healthy building standards. A 2013 study by Healthy Building Network identified a significant number of VOCs in building products that are not covered by leading product certification standards. See Lott, S. and Vallette, J., Full Disclosure Required: A Strategy to Prevent Asthma Through Building Product Selection, Environmental Justice. Dec 2014. ahead of print Published in Volume: 7 Issue 6: December 11, 2014. While some progress has been made since then, there is still much work to be done.