Asbestos air and dust test results, BMCC, Feb 2002

NYC 9/11 Public Portal Document

B.M.C.C. Page 3 Dust & VOC Levels November 14, 2001 None of the areas tested in the Main Building exceeded 40 pg/m3 at PM2.5. Two rounds of sampling was conducted in the early and late afternoon. Most readings were in the range of 10 to 20 pg/m3.

The Portable Trailers, located on West Street, showed higher readings as compared to the Main Building. Most of the higher readings were detected on the first round of sampling. One measurement, in W-103, was 74 pglm3. This reading was collected during class while the instructor was writing with chalk, which may have partially caused the higher reading. Three indoor readings ranged from 42 to 61 pg/m3, and were collected from W-108, W-107, and W-104. It appears that the outdoor levels were more directly impacting the portable trailers as compared to the Main Building.

It should be noted that the higher readings were not duplicated on the second round of testing, except for W-108. All of the other areas, including W-103, were below 40 pg/m3 during the second round of testing. 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.

The outdoor readings indicate that the dust levels vary outdoors. An increase in outdoor levels appears to correspond to an increase in indoor levels in the portable trailers. The higher efficiency filters for the large central air handling units (AHUs) for the Main Building, based on these November 13th readings, are keeping dust levels significantly lower indoors. The grade of filters for the smaller units in the portable trailers are not as efficient in filtering the outdoor air.

TBE recommends using filters with the highest efficiency possible (per manufacturers recommendation) for the HVAC units in the portable trailers. In addition, windows and doors of the portable trailers should be kept closed as much as possible.

VOCs Air Sampling

On November 13, 2001, TBE used a direct reading, portable Photo Ionization Detector (PID) to: (1) compare levels of VOCs in various areas of the Main Building, the Portable Trailers, and outdoors, and, (2) to attempt to locate a possible point source(s) of VOCs that may be affecting the indoor air quality of the spaces.

The Mini-RAE PID is used for the measurement of most VOCs, down to a level of 0.1 ppm (part per million). The sensor consists of a sealed UV light source that emits photons which are energetic enough to ionize many trace species (particularly organics) but do not ionize the major components of air such as oxygen, nitrogen, carbon dioxide, carbon monoxide, or water. The field created on an electrode will drive any ions formed by adsorption of the UV light to the collector electrode where the

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