Asbestos air and dust test results, BMCC, Feb 2002

NYC 9/11 Public Portal Document

B.M.C.C. Page 3 Dust & VOC Levels December 6, 2001 1214 46-87 13-41 54 readings, [Main Building] none exceeded 65 ,,.g/m3, none exceeded 40 m3 12/4 46-87 42-220 25 readings, [Portable Trailers] 5 exceeded 65 .glm3, 20 exceeded 40 m3 1215 31-70 4-19 8 readings, [Portable Trailers with HEPA Air none exceeded 65 .g/m3, Cleanersi none exceeded 40 m3 12/5 31-70 32-39 4 readings, [Portable Trailers] none exceeded 65 g/m3, none exceeded 40 m3

Readings on December 4th were collected over 2 different time periods, 9:30-11:00 am, and 1:00-3:00 pm. Readings were taken throughout the building. This Includes classrooms, common areas, hallways, offices, gymnasium, etc. The December 5th measurements were done only in the portable trailers.

The outdoor readings, collected at various outdoor points, varied over a 2 minute sampling period, with peaks up to 87g/m3. (Readings were collected every second during the sampling)_ These higher peaks would dissipate over a 1 minute range, and most of the outdoor reading on December 4th were In the range of 55 to 65 , g/m3. The outdoor readings on December 4th were higher than the outdoor readings collected on November 13th and November 20th. Two rounds of sampling were conducted, one In the morning and one in the afternoon. One area (at 41,g/m3) tested in the Main Building exceeded 40 g/m3 at PM2.5• The reading was collected by the main entrance and was directly impacted by the open doors. Most readings in the Main Building were in the range of 15 to 25 zg/m3. This was slightly higher than the previous readings, which showed a range of 5 to 20 w-g/m3.

The Portable Trailers, located on West Street, showed higher readings as compared to the Main Building. The range was 42 to 220 v-g/m3, and most readings were in the range of 45-65 v g/m3. One measurement from the morning, in W-108, was 220 "g/m3. This reading was collected during class just after the instructor had erased the blackboard, which released chalk dust in the air. Two other indoor readings ranged from 95 to 150 rg/m3, and were collected from W-104 and W-103, while instructors were writing with chalk on the chalkboard. It appears that: (1) the outdoor levels were more directly impacting the portable trailers as compared to the Main Building, and (2) the use of chalk can cause a rise in the number of fine dust particles.

On the following day, December 5th, eight portable HEPA-filtered air cleaners were places in 8 trailer classrooms (out of 12 trailers), and the dust particles were measured again. A noticeable drop in fine dust particles was recorded, with a range of 4 to 19 ~g/m3 in the trailers with the air cleaners, while the 4 trailers without air cleaners had a range from 32 to 39 g/m3. The portable air cleaners reduced dust levels in the trailers to similar levels detected in the Main Building.

NYC-WTC 000106366