Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002

Our plain-English summary of Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002, by A.S. Geyh, S. Chillrud, D.L. Williams, et al (Journal of Occupational and Environmental Hygiene, 2005).

The study

• Authors: A.S. Geyh, S. Chillrud, D.L. Williams, J. Herbstman, J.M. Symons, K. Rees, J. Ross, S.R. Kim, H.J. Lim, B. Turpin, P. Breysse
• Journal: Journal of Occupational and Environmental Hygiene
• Published: 2005;2(3):179-93
• Cited by: 33 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The destruction of the World Trade Center (WTC) in New York City on September 11, 2001, created a 16-acre debris field composed of pulverized and burning material significantly impacting air quality. Site cleanup began almost immediately. Cleanup workers were potentially exposed to airborne contaminants, including particulate matter, volatile organic compounds, and asbestos, at elevated concentrations. This article presents the results of the exposure assessment of one important group of WTC workers, truck drivers, as well as area monitoring that was conducted directly on site during October 2001 and April 2002. In cooperation with a local labor union, 54 drivers (October) and 15 drivers (April) were recruited on site to wear two monitors during their 12-hour work shifts. In addition, drivers were administered a questionnaire asking for information ranging from "first day at the site" to respirator use. Area monitoring was conducted at four perimeter locations during October and three perimeter locations during April. During both months, monitoring was also conducted at one location in the middle of the rubble. Contaminants monitored for included total dust (TD), PM10, PM2.5, and volatile organic compounds. Particle samples were analyzed for mass, as well as elemental and organic carbon content. During October, the median personal exposure to TD was 346 microg/m3. The maximum area concentration, 1742 microg/m3, was found in middle of the debris. The maximum TD concentration found at the perimeter was 392 microg/m3 implying a strong concentration gradient from the middle of debris outward. PM2.5/PM10 ratios ranged from 23% to 100% suggesting significant fire activity during some of the sampled shifts. During April, the median personal exposure to TD was 144 microg/m3, and the highest area concentration, 195 microg/m3, was found at the perimeter. During both months, volatile organic compounds concentrations were low.

In plain English

This exposure-monitoring study measured the airborne dust and chemical vapors that truck drivers met while hauling debris from the World Trade Center disaster site in New York. Working with a Teamsters local union, the authors recruited 54 drivers in October 2001 and 15 in April 2002 to wear monitors during 12-hour shifts. They also placed area monitors around the site perimeter and in the debris pile. In April, drivers refused to wear monitors, so the monitors were placed in truck cabs instead. Asbestos was also sampled, but those results were left for a later publication. In October, 22 valid personal total dust samples ranged from 72 to 790 micrograms per cubic meter, with a median of 346. The April median was 144. On three October days, the PM10 dust fraction in the middle of the pile was 1.7 to 4.2 times higher than at the perimeter. By April, median perimeter dust concentrations had fallen by 60% to 67%. Volatile organic compounds were found in the parts-per-billion range. The authors noted that no measurements exist from the first days after the attack, when concentrations were highest.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Occupational exposure assessment with personal and area air monitoring, plus a brief questionnaire, at two time points
• Who was studied: Truck drivers (Teamsters local union members) hauling debris at the World Trade Center site, New York City: 54 in October 2001 and 15 in April 2002, plus area monitoring at perimeter locations and in the debris pile or pit
• Exposure: Total dust, PM10, PM2.5, elemental and organic carbon, and volatile organic compounds at the WTC cleanup site. Asbestos was sampled but its results are not reported in this article.
• Main results:
  • October personal total dust exposure: 22 valid samples from 27 monitored work shifts, ranging from 72 to 790 µg/m3
  • Median personal total dust exposure among drivers was 346 µg/m3 in October and 144 µg/m3 in April (April measured in truck cabs)
  • October perimeter area concentrations ranged from 43 to 331 µg/m3 for total dust, 41 to 392 µg/m3 for PM10, and 21 to 321 µg/m3 for PM2.5
  • On three October days with samples at both places, PM10 in the middle of the debris pile was 1.7 to 4.2 times higher than at the perimeter
  • In October, the share of PM2.5 in PM10 ranged from 23% to 100%, and the share of PM2.5 in total dust ranged from 16% to 86%
  • April median perimeter concentrations of total dust, PM10 and PM2.5 were 59, 45 and 19 µg/m3, reductions from October of 60%, 63% and 67%. Pit concentrations in April averaged 8% of October pile concentrations.
  • Volatile organic compounds were in the ppb range. The highest October area value was benzene at 17.8 ppb.
  • In April, the highest area VOC value was MTBE at 27.05 ppb, and the highest personal value was MTBE at 10.02 ppb
  • Questionnaire: in October, 80% of drivers reported using a respirator less than half the time
  • Questionnaire: in April, 87% of drivers reported using respirators more than half the time
• The authors' conclusion: The authors concluded that understanding the changing particle mixture and the large decrease in particle concentrations over time may be important in accounting for potential health effects of these exposures
• Limitations the authors state:
  • Drivers refused personal monitors in April, so exposure was approximated with monitors in truck cabs
  • Concentration data from the middle of the debris pile were very limited
  • Organic carbon may be overestimated because vapors adsorb to quartz filters, so OC results should be read conservatively
  • Eight PM10 and eight PM2.5 samples collected at flow rates outside the target range were kept in the analysis
  • No data exist for the period right after the attack, when concentrations were highest

Topics

Medical terms in this study, explained in our Lexicon: Respirator.

Related studies

• Asbestos exposures to truck drivers during World Trade Center cleanup operations — P.N. Breysse, D.L. Williams, et al. (2005)
• Development of an exposure assessment method for epidemiological studies of New York State personnel who responded to the World Trade Center disaster — M.L. Herdt-Losavio, M.P. Mauer, et al. (2008)
• The legacy of World Trade Center dust — J.M. Samet, A.S. Geyh, et al. (2007)
• Occupational exposures during the World Trade Center disaster response — K.M. Wallingford, E.M. Snyder (2001)
• Health consequences of the September 11 World Trade Center attacks: a review — J. Moline, R. Herbert, et al. (2006)
• Evaluation of vacuum and wet-wipe methods for removal of World Trade Center dust from indoor environments — K.M. Tang, C.G. Nace, et al. (2004)

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