NYC-WTC_000232932

NYC 9/11 Public Portal Document

NYC Response Asbestos Air Sampling Results for WTG Extended Network Data Validation Date; 4/18/02 Sampling Date and Time: 4/12/2002 1200 to 2400 PCM by NiOSH 7400 TEM (AHERA) Sampilng Sampling Sample Structures (#) Date Sample No. Location Volume Matrix f/mm’ f/cc 0,5p - Sp 5iu S/mm’ S~f/cc** 04/12/02 7093-18-0197 Park Row 402 Air <7.0 <0.007 0 0 <8.00 <0.0077 04/12/02 7093-19-0197 Chambers Street 1132 Ail- <7.0 <0.002 0 13.33 0.0045 04/12/02 7093-15-0195 I.S. 143 Manhattan 1440 Air <7.0 <0.002 0 0 <16.00 <0.0043 04/12/02 7094-09-0183 P.S. 154 (Bronx) 1440 Ail- <7.0 <0.002 0 0 <16.00 <0.0043 04/12/02 7096-12-0191 P.S. 199 (Queens) 1254 Air <7.0 <0.002 0 0 <16.00 <0.0049 04/12/02 7095-98-0191 P.S. 274 (Brooklyn) 1406 Air <7.0 <0.002 0 0 <16.00 <0.0044 04/12/02 7097-18-0188 P.S. 44 (S I) 1166 Air <7.0 <0.002 0 0 <13.33 <0.0044

Key: ‘Structure (S) roughly equivalent to fiber (f) ** Sample volume is based on pump reading *** Some Sample volume is below recommended limit for TEM analysis **** Chrysotile NR - analysis not requested NS - Sample not submitted for analysis n/a - Not applicable

NIOSH 7400: Fiber Analysis of Air Sarrspies via NIOSH 7400, Revision 3, issue 2, 8/15/94 Asbestos Fiber Analysis by Transmission Electron Microscopy (TEM) EPA 40CFR Part 763 (AHERA) Standard criteria: EPA 40CFR Part 783 (AHERA): 0.01 fiber/cc (PCM), 70 S/mm^ volume 1200 L, for 25 mm filter (TEM)

O H l"^ to s O o o I o o DDC00948549.XLS

o o Ui

NYC-WTC_000232932