Protocol for identification of airborne asbestos fibres in the urban areas and spatio-temporal trend

Our plain-English summary of Protocol for identification of airborne asbestos fibres in the urban areas and spatio-temporal trend, by Y. Hajizadeh, N. Jafari, M. Mokhtari, et al (MethodsX, 2019).

The study

• Authors: Y. Hajizadeh, N. Jafari, M. Mokhtari, A.A. Ebrahimi, A. Abdolahnejad
• Journal: MethodsX
• Published: 2019;6:2237-2241
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Asbestos is classified as a hazardous pollutants between the airborne particles that cause diseases such as lung fibrosis (asbestosis). This protocol describes an integrated method for determination of asbestos fibres concentration and its temporal-spatial trends in the air of urban areas. To do this, 60 samples were gathered from various areas of Yazd city with low, moderate and high traffic. For analysis of asbestos fibres in the samples scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) were utilized. The spatial and temporal variation of asbestos fibres concentration was carried out by ArcGIS 10 analysis. The Inverse Distance Weighting (IDW) method was used to draw asbestos fibres distribution maps. The interpolation of asbestos fibre by IDW method indicated that the distribution of the fibres in summer and winter were followed almost the similar pattern. However, the distribution of asbestos fibre concentrations in the direction of southeast to the northwest of the city was higher than that in the other areas due to high vehicular traffic.

© 2019 The Authors.

In plain English

This article is a methods protocol describing how the authors measured asbestos fibres in the outdoor air of Yazd, a city in central Iran, and mapped how levels varied by place and season. They grouped 15 sampling points into low, moderate and high traffic areas and collected 60 air samples near main streets in summer and winter, four from each point at 45-day intervals. Filters were examined by scanning electron microscopy with energy-dispersive X-ray analysis. Station averages, reported in fibres per litre, ranged from 1.17 to 2.48 in low traffic areas, 3.72 to 7.08 in moderate traffic areas and 14.25 to 23.22 in high traffic areas. The overall mean was 9.51 fibres per litre, with a standard deviation of 2.03. The difference between low and high traffic areas was reported as statistically significant. About 70% of identified fibres were asbestos, and the types identified were tremolite and anthophyllite. Summer and winter maps showed a similar pattern, with higher levels from southeast to northwest of the city. The authors concluded that heavy traffic, through braking and clutching, can be one of the main sources of asbestos in the city's air.

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: Methods protocol describing an air-sampling and mapping method, illustrated with environmental measurements of airborne asbestos fibres in summer and winter
• Who was studied: Outdoor air at 15 sampling points in Yazd, Iran (a city of more than 656,000 people), grouped into low traffic (S1 to S4), moderate traffic (S5 to S9) and high traffic (S10 to S15) areas. Four samples were taken per point at 45-day intervals, giving 60 samples, at 2.5 m height near main streets. Sampling years are not given.
• Exposure: Airborne asbestos fibres in ambient urban air, counted by scanning electron microscopy when longer than 5 μm, less than 3 μm in diameter and with a length-to-diameter ratio of 3:1. Fibre types were identified by energy-dispersive X-ray analysis. Traffic (car brakes and clutches) is the suspected source.
• Main results:
  • Low traffic stations 1 to 4 had asbestos fibre concentrations (plus or minus SD, fibre/l) of 1.17 ± 2.24, 2.48 ± 0.59, 1.47 ± 2.79 and 1.62 ± 3.41.
  • Moderate traffic stations 5 to 9 had concentrations (fibre/l) of 6.42 ± 2.76, 3.72 ± 2.25, 5.36 ± 1.09, 6.33 ± 1.23 and 7.08 ± 2.14.
  • High traffic stations 10 to 15 had concentrations (fibre/l) of 17.14 ± 0.53, 14.25 ± 2.92, 23.22 ± 3.14, 17.24 ± 1.72, 15.94 ± 0.98 and 19.26 ± 2.56.
  • The mean across all 15 stations was 9.51 ± 2.03 fibre/l.
  • The authors reported a statistically significant difference in asbestos concentration between low and high traffic areas (p less than 0.0001).
  • Summer and winter distribution maps followed almost the same pattern. Concentrations were higher in the southeast-to-northwest direction of the city, which the authors attributed to high vehicular traffic.
  • About 70% of identified fibres were asbestos and 30% were non-asbestos. Tremolite and anthophyllite fibres were identified.
• The authors' conclusion: The authors concluded that heavy traffic can be one of the main sources of asbestos fibres released into the urban air, because of frequent braking and clutching of cars. They also stated that concentrations in Yazd were comparable with WHO recommended standards for ambient air.

Topics

Medical terms in this study, explained in our Lexicon: Fibrosis, Scanning Electron Microscopy (SEM).

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