NYC-WTC_000196071

NYC 9/11 Public Portal Document

AKRF, Inc. 111-115 Broadway, New York, New York

Analytical results revealed levels of VOCs to be below the OSHA, NIOSH and ACGIH exposure limits. Table VI contains a summary of the laboratory results for volatile organic compoimds. A complete copy of the laboratory analysis report is included in Appendix A. Dioxins

Dioxins are a family of 75 chemically related compounds commonly known as chlorinated dioxins. Dioxins are a class of complex hydrocarbon compounds containing chlorine and are closely related to PCBs. Dioxins exist as a trace contaminant in many commercially available products such as some herbicides and pesticides. Dioxins are also produced as a result of heating and combustion and are also formed in flue gases and fly ash. Dioxin (chemically known as tetraclorodibenzo-p-dioxin, “TCDD”) is highly toxic and is not readily excreted. Dioxins can enter the body via inhalation of particles (dust/soot from combustion), ingestion, or absorption through the skin. Overexposure can result in severe acne (chloracne), elevated cholesterol, headaches, numbness in extremities, and gastrointestinal problems. One of the compounds is called 2,3,7,8-TCDD (the number refers to locations of chlorine atoms in the molecular structure). It is the most toxic of the dioxins and is the one most studied. The toxicity of the remaining compounds is compared to the 2,3,7,8-TCDD compound. Equivalency tables are developed based upon these ratios of toxicities. Typically, regulatory limits and values are expressed in TCDD equivalents, utilizing these equivalencies to generate an equivalent dioxin value. Regulatory levels for dioxin exposure vary greatly. NIOSH recommends that the lowest feasible concentration be maintained. No other occupational exposure values exist. Numerous values exist for emission sources. These standards vary greatly (for example, Virginia’s 24-hour standard is 3.00 pg/m^ while Indiana’s yearly standard is 3.0 x 10’^ ug/m‘). Only one sample from the study site revealed dioxin levels above the detection levels. All other samples either revealed no detectable levels or levels below the detector calibration levels. Table VII contains a summary of the laboratory results for volatile organic compounds. A complete copy of the laboratory analysis report is included in Appendix A. 2.7 Temperature, Relative Humidity, Carbon Dioxide and Carbon Monoxide Temperature, Relative Humidity, Carbon Dioxide and Carbon Monoxide concentrations were measured throughout the buildings using a Metrosonics aq-5000 direct read meter. The meter was calibrated prior to initial sample collection. Table VIII contains a summary of the readings obtained for temperature, relative humidity, carbon dioxide and carbon monoxide. Temperature and Relative Humidity ASHRAE standard 55-1992 {Thermal Environmental Conditions for Human Occupancy) defines the environmental conditions that most (90 percent or more) sedentary occupants in indoor environments will find satisfactory. Performance criteria that are established in this standard include the following recommendations for operative temperatures in the occupied spaces: 69 to 76 (degrees Fahrenheit at 30 percent relative humidity) for wintertime conditions. AKRF considers the broad range of relative humidity from 30 to 60 percent as most acceptable for occupant comfort in office environments. Wintertime relative humidities in the 20 to 30 percent range are marginally acceptable but may cause discomfort to sensitive individuals. Humidities below 20 percent are unacceptable because of the effect of dry air on both the mucous membranes and the skin. Relative

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NYC-WTC_000196078