Chrysotile asbestos in urban air

Our plain-English summary of Chrysotile asbestos in urban air, by A.L. Rickards, D.V. Badami (Nature, 1971).

The study

• Authors: A.L. Rickards, D.V. Badami
• Journal: Nature
• Published: 1971;234(5324):93-4
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 005008).

In plain English

This short letter gave a preliminary account of measuring chrysotile asbestos in air near a large asbestos textile factory at Rochdale, Lancashire. Air was sampled in 1970 at the factory and in two house gardens, 5 km upwind and 300 m downwind. An electrostatic sampler collected airborne solids from 1,000 cubic metres of air for X-ray diffraction analysis. Estimated indirectly inside the factory, the sampler's collection efficiency was almost 100% at about 2,000 litres per minute but 25 to 50% at 10,000 litres per minute. Boiling in acid, which decomposes chrysotile but not kaolinite clay, reduced the combined X-ray band in no sample, indicating chrysotile was below the detection limit. Only an upper limit could be given: less than 0.1 μg of chrysotile per cubic metre of air. This was three orders of magnitude below the 1969 Asbestos Regulations' occupational limit of 0.1 mg per cubic metre. Preliminary electron microscopy suggested the true level might be three orders of magnitude lower still. The authors noted methodological uncertainties, kaolinite interference, and sampling only near the factory. They concluded that more sensitive techniques were required.

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: Preliminary environmental air-sampling and measurement study (X-ray diffraction analysis of collected airborne dust)
• Who was studied: Air near a large asbestos textile factory at Rochdale, Lancashire, UK. Two sampling sites were at the factory, and two were in house gardens: one about 5 km upwind and one about 300 m downwind. Samples were taken on dates between April and October 1970.
• Exposure: Airborne chrysotile asbestos. Airborne solids from 1,000 cubic metres of air per sample were collected by an electrostatic sampler and measured by X-ray diffraction of the chrysotile (002) peak. The equipment was calibrated down to 10 μg of chrysotile.
• Main results:
  • The sampler's collection efficiency was estimated indirectly by running it in part of the factory where a low asbestos concentration was known to occur. The estimate was almost 100% at about 2,000 litres per minute, dropping to between 25 and 50% at 10,000 litres per minute, depending on the particle size distribution.
  • After acid leaching, which decomposes chrysotile but not kaolinite, there was no reduction in the intensity of the composite (kaolinite plus chrysotile) X-ray band for any sample. The authors took this to indicate that chrysotile was below their detection limit.
  • Samples from 1,000 cubic metres of air contained less than 100 μg of chrysotile, that is, less than 0.1 μg of chrysotile per cubic metre of air.
  • This upper limit was three orders of magnitude lower than the occupational threshold limit of 0.1 mg per cubic metre set by the 1969 Asbestos Regulations.
  • Preliminary electron microscope examinations suggested the actual chrysotile level may be a further three orders of magnitude below the X-ray detection limit (printed as 'about 0.1 ng').
• The authors' conclusion: The authors concluded that even more sensitive techniques are required, and they reported developing a method based on electron microscopy. They proposed sampling representative urban and rural locations in the UK.
• Limitations the authors state:
  • The technique had several uncertainties, so the authors expected only an order-of-magnitude estimate.
  • Collection efficiency was uncertain because the size distribution of chrysotile in the atmosphere is not known.
  • Kaolinite (probably from local soil) interfered with the chrysotile signal and may have reduced the method's sensitivity.
  • Samples were collected only in the close vicinity of the Rochdale factory.

Topics

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

Related studies

• Human exposure to urban air pollution — C.E. Boström, J. Almén, et al. (1994)
• Monitoring of airborne asbestos fibers in an urban ambient air of Shahryar City, Iran: levels, spatial distribution, seasonal variations, and health risk assessment — F. Taghizadeh, A.J. Jafari, et al. (2019)
• Observations an atmospheric air pollution caused by asbestos — A. Laamanen, L. Noro, et al. (1965)
• Comparative hazards of chrysotile asbestos and its substitutes: A European perspective — P.T. Harrison, L.S. Levy, et al. (1999)
• Spatio-seasonal variation of airborne asbestos concentration in urban areas of Shiraz, Iran — M.K. Fathi Fathabadi, A. Abdolahnejad, et al. (2017)
• Indoor radon levels in urban Hyderabad area, Andhra Pradesh, India — M. Sreenath Reddy, P. Yadagiri Reddy, et al. (2008)

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