Labor relations correspondence regarding site locations, Sep 2001

NYC 9/11 Public Portal Document

«9.8A-Sef.24. 2001x1 5:32PMb associates llo ID»B45 94B S4SeSo.l9S9 P- 6?e6Zl3

4 Adelaide Associates, LLC Temperature and humidity are simple physical factors to measure and , understand. However, they are also the source of over 35% of indoor air quality complaints! Though simple in principle, the control of temperature and humidity is key to good indoor air quality and the perception of good air quality.

Low humidity increases surface static charges which either rape! or attract particulate. The charged dust particles can remain suspended longer in air. This creates ths condition where the total number of particles in a room may not have changed, just tine number airborne. These particles are also of a size and concentration that are usually unmeasurable, in either case.- Low humidity also dries sinus cavities, changes mucous production rates, creates a feeling of pressure in the head (sinus headaches/pressure), and creates dry skin, eye irritation (especially in contact lens wearers), and dehydration.

Elevated humidity decreases surface static charges, and rough surfaces can act as collectors of particles. Elevated humidity also creates the ability ■ for increased microbial growth (mold, fungi and bacteria). Condensation can occur on cold surfaces or cold interfaces (such as uninsulated ductwork, suspended ceiling metal grids, etc.) and create water damage. Odors are more pronounced, and a perception of "not enough fresh air" or "stuffiness" is common.

We found the humidity levels varied throughout the building, between 40 and 65% st all interior locations. Outdoor humidity ranged from 47 to 49%.

Temperature levels within the tested areas varied between 80 to 85 ®F .

Both temperature and humidity levels were elevated, but as mentioned previously once the building systems (HVAC system) are turned on these levels will change.

Ehotoionizable VOCs were non-detected both indoors and outdoors, and there were no obvious chemical supplies or containers within the space

fndv3tii9i / DSHA CampIlanK SsJvicis/ Asb^tot t Ltad CcnwIUng Ccmmuntty Nafae Asseumant/Nasartiatia Uatertal Abatamtnt

.ieceivs^ Tise SeP.2i. 4:2IPM

NYC-WTC_000174829 CITY_21MC100_013493010