Original Article | Published:

An accurate filter loading correction is essential for assessing personal exposure to black carbon using an Aethalometer

Journal of Exposure Science and Environmental Epidemiology volume 27, pages 409416 (2017) | Download Citation

Abstract

The AE51 micro-Aethalometer (microAeth) is a popular and useful tool for assessing personal exposure to particulate black carbon (BC). However, few users of the AE51 are aware that its measurements are biased low (by up to 70%) due to the accumulation of BC on the filter substrate over time; previous studies of personal black carbon exposure are likely to have suffered from this bias. Although methods to correct for bias in micro-Aethalometer measurements of particulate black carbon have been proposed, these methods have not been verified in the context of personal exposure assessment. Here, five Aethalometer loading correction equations based on published methods were evaluated. Laboratory-generated aerosols of varying black carbon content (ammonium sulfate, Aquadag and NIST diesel particulate matter) were used to assess the performance of these methods. Filters from a personal exposure assessment study were also analyzed to determine how the correction methods performed for real-world samples. Standard correction equations produced correction factors with root mean square errors of 0.10 to 0.13 and mean bias within ±0.10. An optimized correction equation is also presented, along with sampling recommendations for minimizing bias when assessing personal exposure to BC using the AE51 micro-Aethalometer.

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Acknowledgements

This work was funded by the United States Department of Health and Human Services (HHS), National Institute of Health (NIH), National Institute of Environmental Health Sciences (NIEHS) under grant R01ES020017. The content of this article is solely the authors’ responsibility and does not necessarily represent official views of the HHS, NIH or NIEHS.

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Affiliations

  1. Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA

    • Nicholas Good
    •  & John Volckens
  2. Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA

    • Nicholas Good
    • , Anna Mölter
    • , Jennifer L Peel
    •  & John Volckens

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The authors declare no conflict of interest.

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Correspondence to John Volckens.

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DOI

https://doi.org/10.1038/jes.2016.71