Mapping roof coverings of asbestos-cement, the first step to control the technical condition/threat and establish priorities for replacement in developing countries

Our plain-English summary of Mapping roof coverings of asbestos-cement, the first step to control the technical condition/threat and establish priorities for replacement in developing countries, by L.K.T. Gil, D. Valdelamar Martínez, K.B. Franco, et al (Heliyon, 2024).

The study

• Authors: L.K.T. Gil, D. Valdelamar Martínez, K.B. Franco, A. Arrieta Pastrana, M. Saba
• Journal: Heliyon
• Published: 2024;10(17):e37522
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

This paper presents a systematic and data-driven approach to prioritize interventions in urban areas with asbestos cement (AC) roofs, addressing the urgent need to mitigate asbestos-related risks. The objective is to propose a comprehensive methodology that considers multiple criteria at the neighborhood level, allowing for a nuanced assessment of intervention priorities. The methodology involves the normalization of various parameters, including population density, facility density, and the area covered by asbestos-cement roofs. In addition, an innovative aspect is introduced by incorporating weathering status identification data, represented as an index, validated in previous research, further enriching the evaluation process. The integration of these diverse factors allows for a holistic understanding of the risk landscape associated with AC roofs in urban settings. The cornerstone of the proposed approach is the development of a Priority Intervention Index (PII) at the neighborhood level. This index serves to standardize the assessment of intervention priorities, enabling a fair and transparent comparison across different regions. To enhance practical application, the PII is discretized into three categories, low, mid and high intervention priority. The results obtained are robust, replicable in other scenarios, and practical for decision-makers. The new methodology provides a structured and quantifiable approach to identify and prioritize areas for asbestos-related interventions based on well-defined criteria at the neighborhood level. The resulting prioritization strategy offers urban planners and local officials a clear and evidence-based tool to allocate resources efficiently and effectively manage the inherent risks associated with AC roofs in urban environments. The paper will describe how the prioritization can be applied "at the neighborhood level" by urban planners and local officials.

© 2024 The Authors.

In plain English

This study proposed a method for ranking neighborhoods in Cartagena de Indias, Colombia, by how urgently their asbestos-cement roofs need attention. The authors examined 149 roof samples by polarized light microscopy. All contained chrysotile (about 40% average volume), and crocidolite was found in 30% of cases, at an average concentration of 10%. Using aerial hyperspectral images, the authors mapped asbestos-cement roofs across 190 neighborhoods. Their model correctly identified 98% of asbestos-cement roofs, with an overall accuracy of 94%. Asbestos-cement roofs covered on average 20.4% of neighborhood area, over 47.6% in some neighborhoods, and 9.1 square kilometres citywide. The authors said they summed six criteria into a Priority Intervention Index but named five: densities of asbestos-cement roof area and of roof area their weathering index rated high priority, population density, facility density, and a socioeconomic score weighted highest for the lowest strata 1 and 2. The highest-priority areas matched strata 1 and 2 neighborhoods. The study included no health data; the authors suggested adding lung health variables in future. The authors concluded that social stratum was a pivotal factor in prioritization.

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: Methodological mapping study combining microscopy of roof samples, aerial hyperspectral imaging and a GIS-based multi-criteria priority index; no health outcomes were measured
• Who was studied: The urban area of Cartagena de Indias, northern Colombia (about one million people, 80.9 square kilometres, 190 neighborhoods), plus 149 asbestos-cement roof samples collected at random; survey dates not stated
• Exposure: Asbestos-cement roofing (chrysotile, with crocidolite in some samples), assessed by roof-area density, weathering condition, population density, facility density and socioeconomic stratum
• Main results:
  • Chrysotile was found in all 149 roof samples (about 40% average volume concentration). Crocidolite was found in 30% of samples, at an average concentration of 10%.
  • Across the 190 neighborhoods, asbestos-cement roofs covered on average 20.4% of neighborhood area, and over 47.6% in some neighborhoods
  • The total asbestos-cement roof area identified in the city was 9.1 square kilometres
  • The classification model correctly identified 98% of asbestos-cement roofs, with an overall accuracy of 94%
  • 18% of the city's neighborhoods showed a moderate presence of high intervention priority roofs
  • Social strata 3 and 4 had the highest density of asbestos-cement roofs, followed by strata 1 and 2
  • The highest-priority areas on the Priority Intervention Index matched neighborhoods in social strata 1 and 2. Strata 5 to 6 and the industrial zone had lower priority.
• The authors' conclusion: The authors concluded that asbestos-cement roofing is pervasive in Cartagena and that social stratum is a pivotal factor in prioritization. In their view, facility concentration drives prioritization in the upper strata.
• Limitations the authors state:
  • Workplace asbestos exposure and comorbidities could not be included because such data are generally not available at large scale
  • The overall accuracy of 94% indicated some classification errors
  • Lung health variables were not included, and the authors suggested future studies add them

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement.

Related studies

• Assessment of asbestos-cement roof distribution and prioritized intervention approaches through hyperspectral imaging — D. Enrique Valdelamar Martínez, M. Saba, et al. (2024)
• Occupational and environmental exposures and cancers in developing countries — D. Hashim, P. Boffetta (2014)
• Interstitial Lung Diseases in Developing Countries — P. Rivera-Ortega, M. Molina-Molina (2019)
• High Time for Complete Ban on Asbestos Use in Developing Countries — T. Chen, X.M. Sun, et al. (2019)
• Asbestos: old foe in 21st century developing countries — L.V. Harris, I.A. Kahwa (2003)
• A case study in avoiding a deadly legacy in developing countries — R.A. Lemen, E. Bingham (1994)

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