Identification and analysis of ambient EMPs

Our plain-English summary of Identification and analysis of ambient EMPs, by D.R. Van Orden (Toxicology and Applied Pharmacology, 2018).

The study

• Author: D.R. Van Orden
• Journal: Toxicology and Applied Pharmacology
• Published: 2018;361:21-26
• Type of article: Review
• Read it: PubMed · Publisher

Abstract

Mineral particles have long been observed in the ambient air and for >40 years, samples of these airborne particulate have been collected in attempt to identify and quantify the amount of asbestos particles in the air. For most of this time, regulated asbestos particles (in the shape of fibers) were the target for these analyses. However, since the turn of the century, more emphasis has been placed on finding and identifying elongate mineral particles (EMPs). For EMPs (particularly serpentine and amphibole minerals), these airborne particles have generally been associated with industrial activities and were reported as "asbestos". Recent monitoring around construction activities involving earth moving have reported concentrations of different mineral particles at sites of varying distance from the activity. The location of detected ambient elongate mineral particles (EMPs) is similar to the locations of soils that also contain EMPs. This close association indicates the necessity for proper mineral identification and valid morphological characterization to allow for source identification. Unfortunately, there continues to be problems with mineral identifications in many studies, regardless of the morphological habit of the particle. This paper addresses the issue of proper mineral identification in ambient air samples.

Copyright © 2018 Elsevier Inc. All rights reserved.

In plain English

This article was a review of how elongate mineral particles (EMPs), a group that includes asbestos, have been collected, identified and measured in outdoor (ambient) air. It summarized earlier studies rather than reporting new sampling. In earlier work by RJ Lee Group, the author's affiliation (Lee and Van Orden, 2008), outdoor air was sampled at 752 buildings in at least 192 US cities. Asbestos was not detected in approximately 84% of samples. Where chrysotile or tremolite asbestos was detected, average concentrations were generally 0.01 structures per cubic centimeter or less. Of these particles, 10.8% of amphibole particles and 2.3% of chrysotile particles were 5 micrometers or longer. Reviewing road-gravel studies, the author noted that disturbing gravel or soils containing EMPs can lead to airborne exposure. The author cautioned that methods have changed over time, so readers should check which procedure a study used. The author concluded that EMPs are ubiquitous in outdoor air and that samples with no detected EMPs need further analysis. The author also concluded there is no clear geographic pattern across the continental US, though local sources can affect 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: narrative review of published and unpublished ambient air data and of sampling and analysis methods
• Who was studied: Ambient (outdoor) air samples from earlier studies, mainly in the continental United States (including RJ Lee Group sampling at 752 buildings in at least 192 US cities), with some studies from Poland, Iran, Italy and China
• Exposure: Airborne elongate mineral particles, including chrysotile, crocidolite, amosite, tremolite, actinolite and anthophyllite asbestos, winchite and richterite asbestos, non-asbestos elongate amphiboles, and fibrous erionite
• Main results:
  • In the RJ Lee Group ambient samples (Lee and Van Orden, 2008), asbestos was not detected in approximately 84% of outdoor air samples (analytical sensitivities 0.001 to 0.004 structures per cubic centimeter)
  • In the samples from that dataset where asbestos was detected, the average concentration was generally 0.01 structures per cubic centimeter or less. For the 215 chrysotile samples, the average was 0.0071 and the maximum was 0.19 structures per cubic centimeter.
  • In that dataset, amphibole asbestos particles were generally longer than chrysotile particles: 10.8% of amphiboles and 2.3% of chrysotile particles were 5 micrometers or longer
  • In Boulder City, Nevada, bypass construction monitoring, the average airborne regulated EMP concentration was 0.0003 fibers per cubic centimeter by direct preparation. Indirect preparation gave about ten-fold higher values (0.0032 versus 0.00038 fibers per cubic centimeter).
  • From the road-gravel studies reviewed, the author stated that disturbing gravel or soils containing EMPs can lead to airborne exposure
  • The author summarized airborne EMP levels as generally 0.001 structures per cubic centimeter or less for fibers of all sizes. For fibers 5 micrometers and longer, levels were usually 0.0001 fibers per cubic centimeter or less.
• The authors' conclusion: The author concluded that EMPs are ubiquitous in the environment and that non-detected samples are ones needing additional analytical work. The author also concluded that there is no clear geographic distribution of EMPs in the continental US, though local sources can affect reported concentrations.
• Limitations the authors state:
  • The search for additional California ambient air data was cursory and limited to California
  • Analytical procedures and counting rules have changed over time, so published data must be read with attention to the method used

Topics

Medical terms in this study, explained in our Lexicon: Regulated Asbestos, elongate mineral particles (EMPs), Serpentine Group, Amphibole Group, Habit.

Related studies

• Analysis and identification of elongated mineral particles in road coated aggregates — E. Leocat, C. Rielland, et al. (2018)
• Measuring EMPs in the lung what can be measured in the lung: Asbestiform minerals and cleavage fragments — V.L. Roggli (2018)
• A comparison of asbestos fiber potency and elongate mineral particle (EMP) potency for mesothelioma in humans — D.H. Garabrant, S.T. Pastula (2018)
• Predicting EMP hazard: Lessons from studies with inhaled fibrous and non-fibrous nano- and micro-particles — G. Oberdörster, U. Graham (2018)
• Mechanistic in vitro studies: What they have told us about carcinogenic properties of elongated mineral particles (EMPs) — B.T. Mossman (2018)
• The epidemiologic evidence for elongate mineral particle (EMP)-related human cancer risk — P. Boffetta, K.A. Mundt, et al. (2018)

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