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While there is no precise definition of "sick building syndrome," the particles in the air of some buildings are believed to cause reactions among some occupants. For some, the reactions are strong enough that they leave the building and/or seek medical attention. There is still no practical way to completely eliminate all the molds, dust, fungal spores, chemical vapors, or other substances from indoor air that might cause reactions. Controlling indoor air quality often starts by providing adequate ventilation to remove these substances and bring in fresh outdoor air. Another way to control indoor air quality is to remove the sources of these substances or prevent their buildup (for example, cleaning and controlling humidity to reduce the growth of mold).
An area of concern some years ago was new carpeting, which sometimes released hydrocarbon vapors into the air. The carpeting industry has made great strides in reducing releases of these vapors, and now regulates itself by establishing standards for emissions. Some advocacy groups have tried to add other man-made materials, including the phthalates in flexible vinyl, as sources of indoor air problems. Additionally, some published articles have discussed the possibility that the plasticizers in vinyl might contribute to sick building syndrome.
But no reliable evidence has linked phthalates in vinyl to the health reactions associated with sick building syndrome. Some forms of vinyl may give off an odor when first unrolled or deployed in work or living space. But these odors are from compounds used in the manufacturing process, and the levels drop quickly. And of course, the mere presence of an odor, even an annoying one, does not necessarily mean that the material being breathed is harmful.
Chances are that the plasticizers in the flexible vinyl used in homes and offices are phthalates. Phthalates by themselves are oily in consistency and have little to no odor. They are tightly bound in the structure of the vinyl and have very low volatility, which means that they do not tend to evaporate. Hence, one would not expect that phthalates would be present at any appreciable level in indoor air. PVC particles containing some phthalates can become a part of household dust as vinyl floor surfaces are abraded. But measurements conducted of airborne dust particles show the amount of phthalates in such particles to be tiny -- at most a few millionths of a gram per cubic meter of air, if they are detectable at all.
New research conducted in Germany and published in 2004 by Becker et al. compared the levels of the phthalates DEHP in household dust to the level of metabolites of DEHP in 254 children. The purpose was to see whether higher concentrations of DEHP in the dust corresponded with higher exposure levels in the children, which would add support to the hypothesis that phthalates in dust could contribute to the induction of childhood asthma. . But the study authors reported that no correlation could be found. A more recent assessment (the abstract is in press) showed that the potential human exposure levels from phthalates in dust is between 100,000 and 1,000,000 times lower than levels in rodents that produced minimal effects indicative of respiratory inflammation.
In all, phthalates are not a likely contributor to "sick building syndrome."
Last Updated: February 22, 2005
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