Sorting out the VOCs

Tom Lent | February 21, 2010

This blog post, originally shared in the Pharos Signal, includes information about parts of Pharos that are no longer available. Please use it for historical reference and for the other useful information it contains.

Pharos Project users may have noticed that products that are advertised as no- or low-VOC, are not necessarily rated highly in Pharos. For most interior finish products, Pharos scores a product based on whether it passes a 14-day test for emissions of VOCs* such as FloorScore, GreenGuard or Indoor Advantage. The system then deducts points for content of chemicals of concern that are flagged in the Pharos Chemical and Material Library. This addresses the non-volatile, toxic chemicals that occupants are exposed to, but the VOC tests don’t measure. Pharos puts a higher weight on the most hazardous of the VOC chemicals.

Pharos evaluates wet applied products, such as the recently-added high performance coatings (including paints, caulks and adhesives) a bit differently; starting with a score based upon the content of VOCs instead of emissions tests. Some of the VOC emission testing programs do certify these products, but these wet products act differently from carpets and particle board, releasing a big blast of hazardous VOCs during the first hours and days of use that these long-term emissions tests aren’t able to tell us much about. At this point, there is lots of disagreement in the emissions lab world about how best to measure and evaluate these short-term VOC releases from wet products.

While the emissions world is working on this problem, Pharos is using the VOC content (sometimes called TVOC for total VOC) to compare products.

Several issues make TVOC a less than perfect protection for human health:


  • The TVOC measure takes different chemical compounds, some of which may be much more potent than others, and combines them into one measure without differentiation. Pharos addresses this by requiring total avoidance of VOCs to reach the upper levels and deducting points for VOC content that is red-flagged, as a material of very high concern.
  • The EPA and some other governmental agencies regulate VOC content to address outdoor smog formation, not indoor air quality. As a result, most manufacturers only report the VOCs that are reactive in the atmosphere and contribute to smog, ignoring those exempted from the EPA smog regulations, but that may still be toxic, such as methylene chloride, a probable carcinogen. Pharos gives higher scores to products which have zero VOCs including exempt compounds (like the Eco-Tuff line of coatings) over others that only claim zero EPA-regulated VOC content.
  • VOC content does not reveal VOCs which may be created by chemical reactions during the curing process, such as methanol or formaldehyde. To reach the highest levels in Pharos, a product needs to have both zero VOC content to protect the user against the early short-term releases and pass a VOC emissions test to insure against the creation of VOCs during longer-term curing. No listed HPCs have done this yet.
  • Occupants are exposed to other non-volatile contents that may be just as toxic as the VOCs, but are not included in either TVOC content or emissions testing. Pharos deducts points to address these low- or non-volatile, but still toxic, chemicals such as the nonyl-phenols found in many of the epoxies.


Pharos staff continues to support efforts to develop improved measures to evaluate both content and short-term emissions of VOCs, and will apply more advanced measures as they are developed.

*VOCs are the Volatile Organic Compounds that outgas from materials after they are made – creating that new carpet smell and releasing toxic gases into your air.