The applicability and challenges of black carbon sensors in monitoring networks

<p>Black carbon (BC) is a particulate pollutant emitted as a by-product of combustion. BC has an emerging role in air quality monitoring with the current recommendations by the World Health Organization to monitor BC to capture its temporal and spatial variability. To observe this variability,...

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Main Authors: J. T. Elomaa, K. Luoma, S. D. Harni, A. Virkkula, H. Timonen, T. Petäjä
Format: Article
Language:English
Published: Copernicus Publications 2025-06-01
Series:Aerosol Research
Online Access:https://ar.copernicus.org/articles/3/293/2025/ar-3-293-2025.pdf
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author J. T. Elomaa
K. Luoma
K. Luoma
S. D. Harni
A. Virkkula
H. Timonen
T. Petäjä
author_facet J. T. Elomaa
K. Luoma
K. Luoma
S. D. Harni
A. Virkkula
H. Timonen
T. Petäjä
author_sort J. T. Elomaa
collection DOAJ
description <p>Black carbon (BC) is a particulate pollutant emitted as a by-product of combustion. BC has an emerging role in air quality monitoring with the current recommendations by the World Health Organization to monitor BC to capture its temporal and spatial variability. To observe this variability, especially in urban areas, a large quantity of sensor-type measurements is required. In this study, four different types of small-scale filter-based BC sensors (AE51, MA200, MA350, and Observair) were used to build a sensor network in Kumpula campus, Helsinki, Finland. Our aim was to test the applicability of the sensors to monitor ambient BC concentrations in field conditions and to study the variation of BC at high resolution. The results were compared to a reference level instrument (multi-angle absorption photometer, MAAP) for validation. During intercomparisons, the sensors had a good correlation with the reference and, after a simple orthogonal regression calibration, were deemed suitable for deployment in the sensor network. During deployment, the sensor network proved to be able to capture small-scale temporal and spatial differences in BC concentrations. Changes in temperature (<span class="inline-formula"><i>T</i></span>) and relative humidity (RH) were observed to induce error in the BC measurements. This error was amplified by the dual-spot correction, which was worsening the measurement result under unstable conditions of <span class="inline-formula"><i>T</i></span> and RH. This should be considered when using sensors that apply the dual-spot correction automatically. The environmental compensation used by the Observair sensors reduced the error from the changing <span class="inline-formula"><i>T</i></span> and RH. To reduce the effect of changing <span class="inline-formula"><i>T</i></span> and RH, more robust environmentally controlled boxes should be developed, or correction algorithms, such as environmental compensation, should be applied.</p>
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spelling doaj-art-05a9b59911f64a6491b9bbbaab2c27872025-08-20T03:07:38ZengCopernicus PublicationsAerosol Research2940-33912025-06-01329331410.5194/ar-3-293-2025The applicability and challenges of black carbon sensors in monitoring networksJ. T. Elomaa0K. Luoma1K. Luoma2S. D. Harni3A. Virkkula4H. Timonen5T. Petäjä6Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, FinlandInstitute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, FinlandAtmospheric Composition Research, Finnish Meteorological Institute, Helsinki, FinlandAtmospheric Composition Research, Finnish Meteorological Institute, Helsinki, FinlandAtmospheric Composition Research, Finnish Meteorological Institute, Helsinki, FinlandAtmospheric Composition Research, Finnish Meteorological Institute, Helsinki, FinlandInstitute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland<p>Black carbon (BC) is a particulate pollutant emitted as a by-product of combustion. BC has an emerging role in air quality monitoring with the current recommendations by the World Health Organization to monitor BC to capture its temporal and spatial variability. To observe this variability, especially in urban areas, a large quantity of sensor-type measurements is required. In this study, four different types of small-scale filter-based BC sensors (AE51, MA200, MA350, and Observair) were used to build a sensor network in Kumpula campus, Helsinki, Finland. Our aim was to test the applicability of the sensors to monitor ambient BC concentrations in field conditions and to study the variation of BC at high resolution. The results were compared to a reference level instrument (multi-angle absorption photometer, MAAP) for validation. During intercomparisons, the sensors had a good correlation with the reference and, after a simple orthogonal regression calibration, were deemed suitable for deployment in the sensor network. During deployment, the sensor network proved to be able to capture small-scale temporal and spatial differences in BC concentrations. Changes in temperature (<span class="inline-formula"><i>T</i></span>) and relative humidity (RH) were observed to induce error in the BC measurements. This error was amplified by the dual-spot correction, which was worsening the measurement result under unstable conditions of <span class="inline-formula"><i>T</i></span> and RH. This should be considered when using sensors that apply the dual-spot correction automatically. The environmental compensation used by the Observair sensors reduced the error from the changing <span class="inline-formula"><i>T</i></span> and RH. To reduce the effect of changing <span class="inline-formula"><i>T</i></span> and RH, more robust environmentally controlled boxes should be developed, or correction algorithms, such as environmental compensation, should be applied.</p>https://ar.copernicus.org/articles/3/293/2025/ar-3-293-2025.pdf
spellingShingle J. T. Elomaa
K. Luoma
K. Luoma
S. D. Harni
A. Virkkula
H. Timonen
T. Petäjä
The applicability and challenges of black carbon sensors in monitoring networks
Aerosol Research
title The applicability and challenges of black carbon sensors in monitoring networks
title_full The applicability and challenges of black carbon sensors in monitoring networks
title_fullStr The applicability and challenges of black carbon sensors in monitoring networks
title_full_unstemmed The applicability and challenges of black carbon sensors in monitoring networks
title_short The applicability and challenges of black carbon sensors in monitoring networks
title_sort applicability and challenges of black carbon sensors in monitoring networks
url https://ar.copernicus.org/articles/3/293/2025/ar-3-293-2025.pdf
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