NYC-WTC_000187673

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan March 20, 2002 Indoor Air Quality Assessment Page 2 P. S. 150M ATC Project No. 15-19125-0289

The assessment was performed consistent with generally accepted indoor air quality assessment practices. As with all such assessments, there were inherent limitations created by constraints of time, operational and work practice variability, variations in indoor air quality parameters and sampling and analytical accuracy. The results of the sampling represent conditions found on the dates of the survey and may not-represent conditions found at other times. The information presented in this report should be used by the BOE as a guide to assess the need for further improvements in current indoor air quality control activities.

EVALUATION CRITERIA

Currently, there are no regulatory standards for indoor air quality in non-industrial buildings, such as offices and schools. For the real-time data collected, ATC uses the commonly accepted guidelines cited in the following publications:

Ventilation for Acceptable Indoor Air Quality (ASHRAE 62-1999), American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE); Thermal Environmental Conditions for Human Occupancy (ASHRAE 55-1992); Industrial Hygienists Guide io Indoor Air Quality Investigations (1993), American Industrial Hygiene Association (AIHA).

Table 1 lists target guidelines for the parameters that ATC evaluated during this investigation. Meeting one, some, or all of the listed values does not assure that acceptable indoor air quality will be achieved at all times.

TABLEI TARGET GUIDELINES FOR INDOOR AIR QUALITY PARAMETERS EVALUATED parameter target le vel AGENCY OR ORGANIZATION Carbon Dioxide <700 parts per million (ppm) ASHRAE 62 (CO2) above background level Carbon Monoxide 9 ppm ASHRAE 62 (adopted from (CO) USEPA NPAAQS) Respirable 65 micrograms per cubic meter USEPA NPAAQS Particulates (PM2.5) of air (pg/m^) 24-hour average 40 pg/m^ 24-hour average USEPA - Recommendation for children / sensitive individuals Temperature Summer: 73-79°F at 50% RH ASHRAE 55 Winter: 68-75°F at 50% RH Relative Humidity 30 - 60 % ASHRAE55 Total Volatile Organic Compounds 1 ppm AIHA (TVOC) USEPA = United States Environmental Protection Agency NPAAQS = National Primary Ambient-Air Quality Standard AIHA = American Industrial Hygiene Association

CITY_21MC100_002954244

NYC-WTC_000187674