The natural reduction of threat in selected systems of old buildings containing asbestos

Our plain-English summary of The natural reduction of threat in selected systems of old buildings containing asbestos, by A. Obmiński (Scientific Reports, 2022).

The study

• Author: A. Obmiński
• Journal: Scientific Reports
• Published: 2022;12(1):2580
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The aim of this study was to measure changes in asbestos dust concentrations over extended use in old building systems. Buildings from different systems during their service lifetimes and after asbestos removal were tested. Asbestos dust concentrations decreased in all building systems due to air exchange and other phenomena in the absence of new active dust sources. Currently, with proper use of those buildings, average values of dust concentrations did not exceed 300-400 f/m3 with a downward trend to < 300 f/m3. The results of these studies were obtained with a modified optical microscopy technique, verified by SEM and TEM methods. The graphical trends in concentration changes over longer periods illustrate the potency of opposing factors reducing and increasing indoor air pollution. If removal asbestos work was not carried out carefully, single measurements conducted in the short-term and mandated immediately after asbestos removal may not detect hazards that appear over time. Monitoring buildings over longer periods allows detection of significant contamination changes. In many cases, the minimal air contamination undermines the desirability of removing asbestos in old buildings.

© 2022. The Author(s).

In plain English

The author repeatedly measured airborne respirable asbestos fibers in typical 1970 to 1990 Eastern European buildings with asbestos products, during use, removal, and afterward. Fibers were counted by modified optical microscopy, checked selectively by electron microscopy. In the "BOLETICE" building, followed 19 years, the highest first-year average while stirring up dust was 16,000 fibers per cubic meter, and the 11-to-15-year average was 3700. After the building closed, such samples averaged 380. In one "LIPSK" building, levels outside the removal work zone peaked at 51000 fibers per cubic meter. Levels rose after removal as wet walls dried, then fell with extra cleaning. In another, where special cleaning rules began after week 10, the author called the decline over the whole test period (p = 0.089) a statistical trend. The most frequent level in rigid buildings was 0 to 300 fibers per cubic meter. The author concluded that air quality in such buildings improved over time. The author also concluded that, absent evidence of rising airborne asbestos, removal should be postponed until the building is no longer used. The author noted the method is inaccurate at extremely low levels.

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: Repeated indoor air measurement study of asbestos-containing buildings over periods of weeks to years (static and dynamic air sampling)
• Who was studied: Typical Eastern European buildings from 1970 to 1990 of several building systems: "BOLETICE" (Czechoslovakia), "LIPSK" and "BERLIN" (East Germany), and "BISTYP" (Polish system). There were 80 measurements in BOLETICE and 40 to 160 measurements for each of the other individual buildings. The total number of buildings is not clearly stated.
• Exposure: Airborne respirable asbestos fibers from building products: "PYRAL" fireproof chrysotile asbestos board; "GLAGIT" hard asbestos-cement plates (13% asbestos); "SOKALIT" soft friable plates (20% asbestos); and PW3/A sandwich panels faced with asbestos-cement plates. Fibers were counted by phase contrast optical microscopy (NIOSH 7400, modified) with polarized light identification, verified in selected cases by SEM and TEM.
• Main results:
  • BOLETICE building, first year of operation: the maximum of the average values was 16,000 f/m3 with dynamic sampling, and the corresponding static-sampling average was 5800 f/m3. Between 11 and 15 years of use, the average was 3700 f/m3 with dynamic sampling and 600 f/m3 with static sampling.
  • BOLETICE building after it was taken out of use: dynamic samples averaged 380 f/m3. Outdoor air about 8 m from the building had a mean below 100 f/m3.
  • LIPSK Building 1, tested outside the work zone during asbestos removal: the maximum was 51000 f/m3 in the fifth week. After removal, levels rose slowly until week 35, which the author attributed to wet walls drying. After additional vacuuming and ventilation, levels fell to 500 to 680 f/m3.
  • Pearson correlation between time and dust concentration over the whole test period, including weeks before the special rules began. For Building 2 (normal use), p = 0.415 and r = −0.274, which the author described as an insignificant association. For Building 3 (special operating rules introduced after week 10), p = 0.089 and r = −0.439, which the author described as a statistical trend of decrease.
  • BERLIN building, contaminated by renovation carried out without knowledge of asbestos: in selected rooms, 20 days of intensive air exchange reduced contamination eightfold. In used rooms, levels were 3810 f/m3 (max 6670) 1 month after renovation and 660 to 750 f/m3 3 years after renovation.
  • The most frequent concentration (mode) of respirable asbestos fibers was 0 to 300 f/m3 in "rigid" buildings with sandwich walls containing asbestos products. In "non-rigid" buildings the range was wider, 0 to 1000 f/m3.
• The authors' conclusion: The author concluded that indoor asbestos fiber concentrations in rigid constructions are most often small (about 0 to 300 f/m3) and that air quality improves over years of operation. The author also concluded that, without evidence of increasing airborne asbestos, removal should be postponed until the building is no longer used.
• Limitations the authors state:
  • The author states that the phase contrast microscopy method does not give accurate fiber concentration measurements at extremely low levels of air pollution.
  • The author states that exact concentrations over a given time interval cannot be determined from the BOLETICE trend graph, because actual room conditions during sampling are not known and different rooms varied considerably at the same time.

Related studies

• An air quality data analysis system for interrelating effects, standards, and needed source reductions: Part 13--Applying the EPA Proposed Guidelines for Carcinogen Risk Assessment to a set of asbestos lung cancer mortality data — R.I. Larsen (2003)
• Worker exposure to asbestos during removal of sprayed material and renovation activity in buildings containing sprayed material — N.W. Paik, R.J. Walcott, et al. (1983)
• Asbestos release from whole-building demolition of buildings with asbestos-containing material — R.A. Perkins, J. Hargesheimer, et al. (2007)
• Does the Presence of Asbestos-Containing Materials in Buildings Post-construction and Before Demolition Have an Impact on the Exposure to Occupants in Non-occupational Settings? — R. Singh, A.L. Frank (2023)
• Mesothelioma among employees with likely contact with in-place asbestos-containing building materials — H.A. Anderson, L.P. Hanrahan, et al. (1991)
• Optimal management program for asbestos containing building materials to be available in the event of a disaster — Y.C. Kim, W.H. Hong (2017)

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