Evaluation of vacuum and wet-wipe methods for removal of World Trade Center dust from indoor environments

Our plain-English summary of Evaluation of vacuum and wet-wipe methods for removal of World Trade Center dust from indoor environments, by K.M. Tang, C.G. Nace, M.A. Maddaloni, et al (Journal of the Air & Waste Management Association, 2004).

The study

• Authors: K.M. Tang, C.G. Nace, M.A. Maddaloni, J.D. Harkay, D.R. Graham, R.N. Koustas, J.D. Rotola, D. LaPosta, K.C. Callahan
• Journal: Journal of the Air & Waste Management Association
• Published: 2004;54(10):1293-8
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The destruction of the buildings at the World Trade Center (WTC) complex dispersed dust and debris into the surrounding area. Pulverized building material made up most of the fallout and was intermixed with combustion byproducts of the aircraft and building contents. A study was conducted to confirm the effectiveness of several cleaning procedures in removing WTC-related contamination from lower Manhattan residences. The contaminants included asbestos, lead, dioxin/furans, synthetic vitreous fibers (fibrous glass), and crystalline silica. All cleaning procedures included the common elements of vacuuming and wet wiping with soap and water. This cleaning procedure combination is effective in reducing WTC-related contamination to below health-based benchmarks. Post-cleaning environmental test results suggested that airborne asbestos measurements can be used as a surrogate parameter in clearance determinations.

In plain English

This U.S. Environmental Protection Agency field study tested whether routine cleaning removed World Trade Center dust from homes. From June to October 2002 it covered 13 apartments in a five-story building across from the WTC complex. All seven cleaning methods combined vacuuming, with or without HEPA filters and air filtration devices, with wet wiping. A unit was cleared when it met health-based benchmarks for asbestos, lead and other contaminants. For airborne asbestos the benchmark was 0.0009 fibers per cubic centimeter. Five apartments met all benchmarks after one cleaning, six after two, and two needed three. Of 45 conclusive airborne asbestos samples, 38 were nondetect, five were at or below the benchmark, and two, from one apartment, were above it. One cleaning cut mean asbestos levels on surface wipe samples by 70%. The authors concluded that vacuuming and wet wiping brought contamination below the benchmarks. They suggested airborne asbestos testing could serve as a practical clearance check, while noting it would not reveal exceedances for other contaminants. They noted the study was not controlled and applied to hard surfaces.

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: Field study of residential cleaning methods, with environmental samples taken before and after cleaning (the EPA WTC Residential Confirmation Cleaning Study)
• Who was studied: 13 residential apartments in one five-story building across the street from the southeast corner of the World Trade Center complex, lower Manhattan; fieldwork June to October 2002
• Exposure: Settled World Trade Center dust containing asbestos (fiber type not specified), lead, dioxin/furans, synthetic vitreous fibers and crystalline silica. It was cleaned using seven methods that all combined vacuuming (household or industrial vacuums, with or without HEPA filtration and air filtration devices) with wet wiping.
• Main results:
  • Five of the 13 apartments met all health-based benchmarks after the first cleaning, and six more met them after the second.
  • The remaining two apartments needed a third cleaning to meet all benchmarks.
  • Of 45 conclusive post-cleaning airborne asbestos samples, 38 (84%) were nondetect and 5 (11%) were at or below the benchmark of 0.0009 fibers/cm3.
  • The other 2 of the 45 samples (4%) were above the benchmark. The value is printed in this text as 0.0015 fibers/cm3, and it cannot be confirmed here whether a comparison sign originally preceded it. Both came from one apartment and were collected using the aggressive sampling technique.
  • After the first cleaning, wipe samples showed a 70% reduction in mean surface loading of asbestos and of synthetic vitreous fibers.
  • After the first cleaning, lead wipe and microvacuum samples showed a 90% reduction in mean surface loading. The authors reported the reductions as statistically significant except for the lead wipe samples (p value given as 0.051).
  • Eight of the 10 additional cleaning events (80%) were prompted solely or in part by inconclusive airborne asbestos results, because dust overloaded the sampling filters.
• The authors' conclusion: The authors concluded that routine vacuuming and wet wiping reduced a complex mixture of WTC-related fibers and particulate matter below health-based benchmarks. They also concluded that airborne asbestos measurement would be a practical surrogate indicator for clearance in residential WTC dust cleanups.
• Limitations the authors state:
  • The study was not conducted under controlled conditions because exclusive access to the building was not granted.
  • Carpeted surfaces could not be studied. Twelve of the 13 apartments had hardwood floors, so the results apply to hard surfaces.
  • Air samples were not routinely collected before cleaning, because settled dust would likely overload the filters.
  • Airborne asbestos testing, used as a surrogate clearance test, would not have revealed benchmark exceedances for other contaminants.

Topics

Medical terms in this study, explained in our Lexicon: Vitreous, Crystalline.

Related studies

• 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 — A.S. Geyh, S. Chillrud, et al. (2005)
• The legacy of World Trade Center dust — J.M. Samet, A.S. Geyh, et al. (2007)
• Summary of the development of a signature for detection of residual dust from collapse of the World Trade Center buildings — H.A. Lowers, G.P. Meeker, et al. (2009)
• 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)
• Case report: Lung disease in World Trade Center responders exposed to dust and smoke: carbon nanotubes found in the lungs of World Trade Center patients and dust samples — M. Wu, R.E. Gordon, et al. (2010)
• Potential carcinogenic effects of world trade center dust after intratracheal instillation to Sprague-Dawley rats: first observation — M. Soffritti, L. Falcioni, et al. (2013)

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