Developing a Relative Humidity Correction for Low-Cost Sensors Measuring Ambient Particulate Matter.
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Publication Date
2018-08-24Journal Title
Sensors (Basel)
ISSN
1424-8220
Publisher
MDPI AG
Volume
18
Issue
9
Language
eng
Type
Article
This Version
VoR
Physical Medium
Electronic
Metadata
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Di Antonio, A., Popoola, O., Ouyang, B., Saffell, J., & Jones, R. (2018). Developing a Relative Humidity Correction for Low-Cost Sensors Measuring Ambient Particulate Matter.. Sensors (Basel), 18 (9) https://doi.org/10.3390/s18092790
Abstract
There is increasing concern about the health impacts of ambient Particulate Matter (PM) exposure. Traditional monitoring networks, because of their sparseness, cannot provide sufficient spatial-temporal measurements characteristic of ambient PM. Recent studies have shown portable low-cost devices (e.g., optical particle counters, OPCs) can help address this issue; however, their application under ambient conditions can be affected by high relative humidity (RH) conditions. Here, we show how, by exploiting the measured particle size distribution information rather than PM as has been suggested elsewhere, a correction can be derived which not only significantly improves sensor performance but which also retains fundamental information on particle composition. A particle size distribution⁻based correction algorithm, founded on κ -Köhler theory, was developed to account for the influence of RH on sensor measurements. The application of the correction algorithm, which assumed physically reasonable κ values, resulted in a significant improvement, with the overestimation of PM measurements reduced from a factor of ~5 before correction to 1.05 after correction. We conclude that a correction based on particle size distribution, rather than PM mass, is required to properly account for RH effects and enable low cost optical PM sensors to provide reliable ambient PM measurements.
Sponsorship
Natural Environment Research Council (NE/I007490/1)
Natural Environment Research Council (NE/N007093/1)
Identifiers
External DOI: https://doi.org/10.3390/s18092790
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286939
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