NYC 9/11 Public Portal Document
Asbestos in Air Page 1 of 2
US. Envintii&ental Pmtocffon Agency
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EPA Response to September 11
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Response to 9-11 > Monitoring Data > Asbestos in Air > Church & Duane
Monitoring Summaries
Monitoring Data EPA Monitoring Site:
Frequently Asked Church & Duane (No Longer Active)
Questions
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Asbestos Air Monitoring Data
EPA Press Releases
How You Can Help This table shows how much asbestos EPA measured in the air at this site, on the
dates and times shown. Daily summaries of this data and how it compares to the
level of concern for public health are also available.
EPA can measure asbestos in several ways. For these data tables, EPA is
providing measurements in terms of the number of asbestos structures found per
square millimeter within our air monitors (structures can include single, overlapping,
and bundles of asbestos fibers). The level of concern for asbestos is based on
continuous exposure to more than 70 structures per square millimeter for an
extended period. Because cleanup efforts will reduce asbestos levels
dramatically over the next several weeks, EPA does not expect people
exposed to this amount of asbestos to have increased risks of health
problems.
Measurement*
Date Time (structures/square millimeter)
09/17/2001 8 am to 8 pm Not Detected
09/17/2001 8 pm to 8 am(09/18) Not Detected
09/16/2001 8 am to 8 pm 16+
09/16/2001 8 pm to 8 am(09/17)
09/15/2001 8 am to 8 pm 64+
09/15/2001 8 pm to 8 am(09/16) Not Detected
09/14/2001 8 pm to 8 am(09/15) 32+
Description of the Benchmarks, Standards, and GuLdJines used to Evaluate
Environmental Conditions.
*The information contained in this database should be considered provisional and
may be subject to adjustment upon final analysis.
tThese results are different from the concentrations previously reported on this
website. The previous results included an additional, unnecessary adjustment for
the volume of air sampled. The corrected values listed now are the result of the
same methods used for more recent data. The corrected asbestos concentrations
are generally lower than the previously reported values, but use the correct method
for calculating the effect of the volume of air sampled.
There may be gaps in daily readings because of relocated construction equipment
and variations in sampling locations.
http://oaspub.epa.gov/nyr/asbestos_monitoring?p_addr_id=Mll 3/11/02
NYC-WTC_000147315
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