WTC environmental health assessment draft, May 2002

NYC 9/11 Public Portal Document

Polycyclic Aromatic Hydrocarbons (PAHs)

Tier Action PAHs (settled dust) PAHs (indoor air)

Level Basis Level Basis

I Aggressive >9 nig/nr Risk-based >6 ug/m^ Risk-based cleaning. If levels screening level screening level persist, take for residential for residential additional action to setting (E-04 X setting (E-04 x reduce exposure. PtO 9 mg/m" 6 ug/m’ represents a represents a IX10* risk 1X10-^ risk . estimate for a 1 estimate for a 1 year exposure' year exposure

n Maintain 9 mg/m’ to 0.3 0:9-mg/1112 is 6 ug/m’ to 0.2 0.2 ug/m3 is recommended mg/m^ Risk- bnsed ug/m’ (or Risk- based cleaning methods. screening level background) screeningdevcl Consider for resrdenti al for residential additional setting (E-04-X sctting4B=04-x monitoring 3^ 9^ 0.3 mg/nr 0.2 ug/m’ represents a represents a 1X10* risk 1X10 * risk estimate for a estimate for a 30 year 30 year exposure exposure

in No further action <0.3 mg/m* (or Determination <0.2 ug/m’ (or Deteiiiiiiiation background) of local background) ofdocal background background Level could also Level could be set at that also be set at found in that found in background, or background, of unaffected, unaffected, areas, so that no areas, so that increase in risk no increase in due to PAHs risk due to would be PAHs would expected.; be expected.

PAHs are a large group of compounds that are evaluated as benzo(a)pyrene-equivalents. <need more explanation ofmethods>

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CONFIDENTIAL, CITY_21MC100_003423795 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

NYC-WTC_000176166