NYC 9/11 Public Portal Document
B.M.C.C. Page 4
Dust & VOC Levels November 14, 2001
current (proportional to concentration) is measured. Response time for this direct
reading instrument is under 5 seconds.
TBE found that readings in the Main Building were in the range of 0.1 to 1.0 ppm of
VOCs. The nearby portable trailers had a range of readings from 0.7 to 1.4 ppm. The
outdoor VOC levels ranged from 0.4 to 2.0 ppm.
Almost all of the indoor readings were less than 1.0 ppm. This was mostly the case for
the outdoor levels as well. The instrument that was used (a PID) is very sensitive, and
will detected perfume, nail polish, and office supplies. TBE, in past indoor air surveys in
other buildings, has detected indoor levels of VOCs using the PID in the range of 0.5-
0.7 ppm, when the outdoor levels were in the range of 0.1-0.2 ppm. At B.M.C.C., the
outdoor levels were impacting the indoor levels.
At present, no single organization develops guideline concentrations for indoor air
contaminants nor are values available for all contaminants of potential concern. A
number of organizations offer guideline values for selected indoor air contaminants.
These values have been developed primarily for occupational settings and, in some
cases, for residential settings. The values for individual VOCs are generally in the
range of 5 ppm and above.
TBE will be conducting further testing next November 20th, to ascertain if VOC or fine
dust particle levels have changed.
Sincerely,
John A. Tiffany,
President, TBE
NYC-WTC 000106352
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