Letter enclosing air monitoring report, 75 Maiden Lane, Mar 2002

NYC 9/11 Public Portal Document

03/06/2002 08:03 2125450757 ADVANCED ENVIRONMENT PAGE 03

Recovery Physical Air Monitoring for Asbestos, Respirable Dust, and Priority Pollutant Therapy Room, 79 aiden Lane,NYo NY Tner"y Advanced environmental Corp.

In accordance with the sampling protocol a Gillian 10-mm nylon cyclone was utilized during sample collection. The concept of the cyclone is to separate respirable dust from particulate matter of 10 micron pore size or greater. With the air flow: rate calibrated: to:`1 7 LPM, the cyclone inlet draws in the air and Creates a spiral action or vortex, which separates the larger particles from the lighter ones. The cyclone 'S. grit pot accepts the heavier particles while the lighter (less than. 10 microns) are drawn up and impacted onto the filter cassette.

The sample data is presented as a ration of particulates measured. (by weight) per volume of air collected, The sample results indicated a Total Respirable Dust (or PNOC) concentration of 0.0173 mg/m3' which is well below the OSHA Permissible Exposure Limit (PEL)• of 5 mg/m3. These results can be found in Appendix B.

Metals

Sampling was performed to determine levels of priority pollutant metals in the ambient air. One (1) sample was collected and analyzed according to EPA 1987 Methods 200.7 and 245.1 for priority pollutant metals analysis. The sample was collected on a 0.8-µrn pore size mixed cellulose ester filter using a 37 millimeter cassette. A low flow volume personal air pump weas used to draw air through the filter media. Plow rates were measured with a Mini Huck calibrator model M-30, before and after sampling to ensure an accurate volumetric reading. The sample was collected closed face in accordance with the sampling protocol.

The priority pollutant metals tested include Antimony, Arsenic, Beryllium, Cadmium, Chromium, Copper, Lead, Mercury, Nickel, Selenium, Silver, Thallium, and Zinc. The sample results detected no airborne concentrations of priority pollutant metals with the exception of chromium. The sample result indicated a total chromium concentration of 0.61g µg/m'' which is well below the OSHA Permissible Exposure Limit (PEL) of 500 µg water soluble chromium (III) compounds per cubic meter of workplace air (500 µg/m3), 1,000 µg/m3 for metallic chromium (0) and insoluble chromium compounds, and 52 µg/m3 for chromium (VI) compounds for 8-hour work shifts and 40-hour work weeks.

These results can be found in Appendix C

Summary

In conclusion, sample data obtained for asbestos, respirable fraction dusts, and priority pollutant metals, are well below applicable exposure standards for these substances. If you have any questions or need further clarification on air sampling methodology, please call me.

Sincerely,

Edward Namath Principal

1213.001 Uapgeenyerl Uffita~=WientsWee4vey Phrsica1\79 maiden air mnp rptdoe

347 Fifth Avenue, Suite 404, New York, New York 10016 Phone 212-545-1855 Fax 212-545-0757

NYC-WTC 000097353