NYC-WTC_000220400

NYC 9/11 Public Portal Document

HiUmann Environmental Group, LLC

SECTION 2 ■ INTRODUCTION

2.1 General. Hillmann Environmental Group, LLC performed an Indoor Air Quality Investigation at the request of Mr. Joseph Rizzuto, of Cushman & Wakefield, as a result of the recent World Trade Center collapse. This survey was performed in 44 Wall Street, New York, NY.

On four dates, Hillmann’s site investigator, Jennifer L. Collins, IH, performed a visual inspection and conducted air sampling of the subject space to identify conditions that could negatively impact indoor air quality. Sampling was conducted on September 15*, 2P‘ and October 4* and 5*, 2001.

Indoor air quality problems are caused by the combination of many factors and contaminants, including temperature, relative humidity, carbon dioxide, carbon monoxide, dust, microorganism growth, formaldehyde, ozone, nitrous oxides and hydrogen sulfide.

The inspection and sampling are performed by trained industrial hygienists using Environmental Protection Agency (EPA) and National Institute for Occupational Safety and Health (NIOSH) sampling techniques. Samples are analyzed at an appropriately accredited laboratory. These samples, representative of a narrow time frame, are for screening purposes only and are not intended to represent definitive exposure levels.

2.2 Sampling Parameters and Methodology. The chosen sampling parameters were temperature, relative humidity, carbon dioxide, carbon monoxide, volatile organic compounds, hydrogen sulfide, oxygen, combustible gasses and airborne asbestos. Hillmann selected the sampling parameters based on consultations with the client, the laboratories performing the analysis and our in-house experts. The inspection is a general screening to identify if potential hazards exist.

The industrial hygienist employed a sampling scheme that is representative of the average working environment and accounts for the entire subject space. Sampling parameters were based on common indoor air pollutants.

1. Temperature, relative humidity (RH), carbon dioxide (CO2) and carbon monoxide (CO) levels are measured using a TSI Q-Track 8551 direct reading monitor. The monitor measures CO2 from 0 ppm to 5000 ppm in 1 ppm increments and CO from 0 ppm to 500 ppm in 1 ppm increments.

II. Volatile Organic Compound Levels were measured by using a direct reading Rae Systems Mini Rae 2000 Photo Ionization Detector (P.I.D.). The P.I.D. has a range of 0 to 2000 mg/m^ and an accuracy of ± 2 mg/m’ or 10% of the reading. The P.I.D. semi-quantifies volatile organic compound levels by ionizing these compounds using an electrodeless 10.6 eV ultraviolet discharge lamp. The ionized compounds give off an electrical signal that is translated into a reading. The investigator compares the readings taken within the subject space to a background reading, taken outside. The limit of detection of the P.I.D. is 0.1 mg/m^.

III. Hydrogen Sulfide (H-Sj concentrations were analyzed utilizing a Rae Systems Multi-Rae Four Gas meter. The range and limits of detection for this meter depends on the gasses being tested for. The Hydrogen Sulfide range is 0-100 ppm and a 1.0 ppm limit of detection.

rV. Oxygen (O;) levels were measured using a Multi-Rae Four Gas meter with a limit of detection of 0.1%.

Cushman & Wakefield/44 Wall Street, New York, NY/Project Number N3-7476 Page 3

CITY_21MC100_002388354

NYC-WTC_000220405