VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

FOREWORD

The National Center for Environmental Assessment (NCEA), a major component of the Office of Research and Development (ORD), is EPA's national resource center for human health and ecological risk assessment. NCEA conducts risk assessments, carries out research to improve the state-of-the-science of risk assessment, and provides guidance and support to risk assessors.

Following the collapse of the World Trade Center towers on September 11,2001, New York State and Federal agencies initiated numerous air monitoring activities to better understand the ongoing impact of emissions from the disaster. This report focuses on these air measurement data, evaluating them in terms of what is typical for New York City or general urban background and interpreting it with regard to the potential for human health consequences. The report does not evaluate exposures possibly faced by rescue or clean-up workers and briefly discusses past and current indoor monitoring efforts.

The analysis in this report supports three general findings: 1) Persons exposed to the extremely high levels of ambient particulate matter and its components during the collapse of the World Trade Center towers and for several hours afterwards were likely to be at risk for immediate acute (and possibly chronic) respiratory and other types (e.g., cardiovascular) of symptoms. 2) The first measurements of some of the contaminants were on September 14, while other contaminants were not measured until September 23. Available data suggest that the concentrations within and near Ground Zero were likely to be highest in the few days following September 11. Because there are only limited data on these critical few days, exposures and potential health impacts cannot be evaluated with certainty for this time period. 3) Except for exposures on September 11 and possibly during the next few days, persons in the surrounding community were unlikely to suffer short-term or long-term adverse health effects caused by exposure to elevations in ambient air concentrations of the contaminants evaluated in this report. These elevated concentrations were measured mostly within and near Ground Zero, and they lasted for one to three months after September 11. The monitoring data indicate that air concentrations decreased to background levels that are characteristic of pre-September 11 levels in the New York City metropolitan area by around January or February of 2002.

Ultimately, it will be difficult to ascertain with certainty what effects resulted when people were surrounded by initial clouds of dust, or were subsequently exposed to the elevated concentrations that are discussed in this report. Epidemiologic studies of the exposed populations that are being conducted by various agencies and institutions should provide a more scientifically robust evaluation for future evaluations of health effects.

George W. Alapas Acting Director National Center for Environmental Assessment

DRAFT-DO NOT QUOTE OR CITE X October 2002

NYC-WTC_000149079