NYCDOH/ATSDR asbestos residential sampling results, Apr 2002

NYC 9/11 Public Portal Document

households are included), 1.5 is proposed as the multiplier, resulting in a value of 60 pg/m’ (It may be necessary to revisit this value if the ratio for the control homes differs from the historical data, or if EPA has additional information that would support a different multiplier.). Contribution from a smoker in the home was estimated in various studies described in the 1996 Criteria Document for PM as contributing 20 to 45 pg/m’ to PM 2.5 time-averaged measurements (12-24 hour samples). The concentration of PM at street level monitors can vary greatly from concentrations measured at monitors sited in accordance with EPA's requirements. The influence of traffic (how much, what types of vehicles), the presence of bus stops or traffic lights and wind patterns associated with "urban canyons" are all factors that will influence particle concentrations at street level. Of the limited number of studies identified that looked at differences between area and street-level monitoring results, street level results were reported to be about 1.3 times higher than area type monitor results for the same time period. From historical data collected in Manhattan at a rooftop monitor and a street level monitor the ratio for average street/area concentrations of PM 10 was about 1.3, and about 1.5 for PM2 5. Limited data for an additional street-level monitor in NYC produced similar ratios for each particulate fraction. ’Cooking was estimated to add 10-20 pg/m’ to 12- hour PM|o concentrations. * The ACGIH TLV (8 hour TWA) for inhalable particulate matter, not otherwise classified is 10 mg/m’, and is intended to be protective against worker irritation. A screening value could be developed by applying uncertainty factors such as a ten-fold uncertainty factor for sensitive sub-populations or for longer than work day exposures. ’ Developed by assuming a straight line correlation between PM2.5 and PM|o and then using the associated line slope factor to determine the screen guideline. The guideline was rounded down to the nearest whole ten number. *Screening Guidelines = are levels for the general public that require further evaluation. Levels measured above a screening value does not indicate that adverse health effect will result. ** As sampled in “Ambient and Indoor Sampling for Public Health Evaluations of Residential Areas Near WTC.”

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NYC-WTC_000164827