Asbestos air and dust test results, BMCC, Feb 2002

NYC 9/11 Public Portal Document

BMCC, Portable Classrooms Page 2 Tiffany-Bader Envir. December 22, 2001 hour period. EPA lowers the level of concern for sensitive groups, including children, the elderly, and people with heart or lung disease, to 40 rgIm4 averaged over a 24 hour period.

According to the EPA, when outdoor levels exceed 40 rg/m3 over a 24 hour period, people with respiratory disease, such as asthma, should limit outdoor exertion. Also, the EPA states, when outdoor levels exceed 65 rg/m3, people, especially the elderly and all

children should limit prolonged outdoor exertion. The EPA Web site for particulate testing related to the World Trade Center disaster states most healthy adults and children are expected to recover quickly from any symptoms of short-term exposure like coughing, wheezing, or eye and throat irritation. EPA expects the long-term risk from these short-term exposures to be low."

The EPA is collecting PM2.5 using gravimetric samplers, while TBE is using a laser particle counter (the TSI Dust Trak). According to TSI, some studies have shown that the Dust Trak sampled approximately 3 times more than the gravimetric samplers. This higher sampling efficiency may cause higher readings for the Dust Trak as compared to gravimetric samplers. The EPA's Air Quality Index standard is averaged over a 24 hour day. TBE was collecting direct reading levels, at that point in time. The levels detected were not averaged over a 24 hour period.

TBE collected readings from 10 AM to 12 PM on December 19th in the portable classrooms. The readings outdoors, which ranged from 19 to 30 glm ; this relatively light loading outdoors reflected the impact of several days of rain. The reading in the portable classrooms were all lower than the outdoor readings, with a range of 1 to 14 W-g/m 3. The highest reading indoors [14 rg/m3] was in a classroom with the HEPA air cleaner turned off. Using the HEPA air cleaners show a marked difference in fine dust particle levels.

TBE recommends that the HEPA air cleaners be kept on during any occupancy in the portable classrooms. As much as possible, doors and windows should be closed.

Following is a summary table of PM2.5 particulate testing done on the morning of December 19, 2001.

NYC-WTC 000106375