The Woods Institute is now part of the Stanford Doerr School of Sustainability
More than 15 percent of Americans report sensitivities to indoor environments a condition known as "sick building syndrome."
Volatile organic compounds (VOCs) are a complex group of gaseous air pollutants which are known to be especially elevated inside modern buildings. On average, urban dwellers are exposed to VOC levels, including persistent organic pollutants (POPs), that are 2 - 20 times as high as outdoor levels, due mainly to the fact that they spend 90 percent of their time indoors. Some VOC species have been identified as probable human carcinogens or known mutagens; others are known to cause damage to the liver, kidney or nervous system.
Many commonly used materials, furnishings and products present in the indoor environment emit chemicals which are resistant to degradation, and the average U.S. resident spends >21 hrs/day indoors, inhaling these POPs.
Measuring VOC concentrations has long posed a challenge. Current state of the art in the environmental field for airborne VOCs involves passing an air sample through a sorbent cartridge, or collecting it inside an evacuated stainless steel canister. The sample is analyzed, usually days later, via gas chromatography with mass spectrometry (GC/MS), at a cost of less than $200 per sample. Analysis of bodily dose levels is even more expensive, requiring collection of either blood samples or breath samples, followed by a pre-concentration step and then GC/MS analysis. The effort and expense involved, and the need to regularly analyze VOC standards for each species of interest to ensure accurate quantification, has greatly limited the scope and time resolution of studies investigating indoor VOC levels and human exposure to VOCs. In addition, some especially irritating VOCs present at lower concentrations can be left undetected via this approach these undetected VOCs have been hypothesized to contribute to sick building syndrome.
Utilizing new laser technology, the EVP team will develop a portable instrument that measures volatile organic compounds in air and breath samples with unprecedented speed and accuracy.
Lynn Hildemann Professor of Civil and Environmental Engineering