E-mails M. Gilsenan 2002

NYC 9/11 Public Portal Document a. Based on consultation with resident or owner, aggressive or modified aggressive air sampling will be conducted. Residents shall not be present in their apartment during aggressive air sampling activities. We do not see the benefit or need to use a leaf blower to aggitate the indoor environment to this extent during sampling. An electric leaf blower is capable of producting air velocities of 155 to 210 mph according to Sears. These air velocities are far removed from any air velocities that occur in indoor environments. (And. yes, you can reduce the air velocities from a leaf blower to some extend, but what is the point?) We understand that such a technique was used in miners'cabins in Montana but this is less than pursuasive given the differences between those indoor environments and those ofoccupied apartments in Manhatten. Why would we do this? What is the benefit? We are not aware of any expert on indoor air quality who has used or would advocate the use of such high air velocities. In addition, the fact that we propose that the resident orowner decide whetherto use aggressive (leaf blower) or modified aggressive sampling protocols suggests that the aggressive protocol is not core or key to our study. Moreover, it will add another stratificationto our study and reduce our power to interpret the study results. There is also the potential to damage furnishings in the dwellings throug the use of thistechnique. It will only take a few highly publicized incidence to tarnish our whol effort..We recommend that we do not propose the use of the aggressive sampling protocol. b. d. i. Before beginning aggressive air sampling, forced air equipment (such as a t horsepower electric leaf błower) shall be used to direct exhaust air against walls, ceilings, floors and other surfaces. When directing the exhaust, caution shall be taken to minimize disturbance and potential damage to furnishings and personat belongings. ii. Formodified aggressive air sampling forced air equipment shall not be employedt. The terminology used here is incorrect and confusing because a 20-in fan is a form of forced air equipment. iii. All other procedures are identical for aggressive and modified aggressive air samphing: One 20-inch fan shall be installed per 10,000 cubic feet of room space and run at low speed. The fan shall operate continuously throughout sampling and shall not be turned off until sampling is completed. How long before sampling should the fan be turned on?. This is an important issue because we want to sample at or near steady state and the air moved by the fan has a time constant the will partially determine how long it will take to achieve steady state. Ata minimum. the time prior to sampling when the fan should be turn on should be specified. For studio apartments 3 air samples shall be collected. For 1-bedroom apartments and above 5 air samples shall be collected. Sampling equipment shall be placed in living areas and away from obstructions. The sampling cassette must be placed on a tripod directed downward at a 45 degree angle and not taped to existing surfaces. Common spaces will be sampled without the use of forced air devices (fans, leafblowers ete): For small spaces, less than 160 square feet, 3 air samples will be collected. Forlarge NYC-WTC_000164035