VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

respiratory effects (such as lung inflammation and exacerbation of asthma) and cardiovascular effects (including exacerbation of preexisting chronic heart disease). As with exposures to other environmental contaminants, potential health impacts depend on PM concentrations and duration of exposure, as well as the size of the particles inhaled and many other factors (including the age and health status of exposed individuals). Depending on age and health status, some groups (such as infants and children, the elderly, and/or individuals with preexisting cardiovascular or respiratory diseases) may be considered sensitive or susceptible populations to possible effects of PM exposure.

Particulate matter is one of six common, widespread air pollutants (the others are ozone, carbon monoxide, nitrogen oxides, sulfur dioxide, and lead) for which EPA has set National Ambient Air Quality Standards (NAAQS). A NAAQS is an air quality standard, set under the Clean Air Act, that is designed to protect public health. In 1987, EPA set PM,o NAAQS (150 pg/m’, 24-hour average, and 50 pg/m’, annual average, averaged over 3 years) to protect against health risks associated with inhalable particles (mainly those <10 pm diameter) that can deposit in lower (thoracic) portions of the human respiratory tract. These health-related PM,o particles include both fine particles < 2.5 pm diameter (PM2 5) and a subset of coarse particles larger than 2.5 pm but less than <10 pm diameter (PMi(,.2 5). After reviewing the scientific bases for PM NAAQS in 1996, EPA concluded that fine and coarse components of PM,o particles should be treated as separate classes of pollutants. Thus, EPA moved in 1997 to set an annual PM2.5 NAAQS (15 pg/m\ annual average, averaged over 3 years) to protect against both short- and long-term exposures and a supplemental 24-hour average PM2.5 NAAQS (set at 65 pg/m^) to protect against unusually high peak levels to decrease health risks associated with fine particle exposures. The PM,o NAAQS were retained to address risks related to coarse particles. As more scientific evidence becomes available, consideration may be given to setting PM standards for shorter averaging periods (< 24 hr).

Also, to provide real-time, day-to-day information to State and local health officials and the public, EPA established an Air Quality Index (AQI) level of concern (LOC) for daily PM2.5 ambient concentrations at 40 pg/m’. The AQI is meant to provide reference points forjudging levels of potential health concern and to guide actions by citizens or government officials to protect the health of the public, including susceptible groups. Thus, in order to minimize risk of potential health effects among highly susceptible individuals (e..g, the elderly over 65 yr old or individuals with preexisting chronic cardiovascular or respiratory disease), actions should be taken to reduce or avoid exposures of such persons to 24-hour PM2 5 concentrations above 40 pg/m^

IV.a.l. Air Quality Monitoring of Ambient Particulate Matter Mass/Composition At the time of the September 11, 2001, WTC attack, there were no monitoring sites measuring ambient air PM2 5 or PM,o concentrations in the immediate vicinity of the WTC or surrounding neighborhoods in lower Manhattan, except for PM instruments operating at the Canal Street Post Office about a half mile north of the WTC. However, there were numerous New York State-operated PM sampling sites monitoring ambient air PM concentrations at various other locations throughout the five boroughs of New York City (NYC), with most measuring PM2.5 levels by Tapered Element Oscillating Microbalance (TEOM) monitors.

DRAFT-DO NOT QUOTE OR CITE 25 October 2002

NYC-WTC_000149106