NYC-WTC_000226955

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan Januaiy' 7, 2002 Air Sampling for Mercury Page 2 Stuyvesant High School ArCProiectNoH5H9125-0246

TABLE 2 Airborne Mercury (Hg) Concentrations* December 26, 2001

(micr(iVrarns>'; 0.028 96 0.000292 1 Floor Main Lobby hF2 0.03 96 0.000312 2"" floor bridge lobby Hi^s 0.029 96 0.000302 Roof Hi^^4 0.025 Blank * milligrams per-cubic meter of air / Not b ank corrected

After the Hg level in the blank is subtracted, the maximum concentrations in the indoor samples drop to below the detection limit on December 20"' and 0.000052 mg/m^ on December 26*. The 1 outdoor levels drop to below the limit of detection on December 20* and 0.000042 mg/m^ on December 26*.

There are currently no federal ambient air standards for mercury. The Occupational Safety and Health Administration’s (OSHA) Permissible Exposure Limit (PEL) for mercury is l.Omg/lOm^ (O.lmg/m^). This is considerably above the levels that were detected or that Would otherwise be expected in a school or office and it is not an applicable standard.

Mercury was detected in the samples at levels just above the detection limit. / ATC appreciates the opportunity to provide this indoor air quality service to the BOE. Please call me at (212) 353-8280 extension 212 if you have any questions.

Sincerely, ATC Associates, Inc.

James R. Cohn, CIH, CSP Regional Manager Industrial Hygiene Division

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CITY_21MC100_000490954 NYC-WTC_000226956