Crilley, Leigh R., Shaw, Marvin David orcid.org/0000-0001-9954-243X, Pound, Ryan Joseph orcid.org/0000-0003-1547-6565 et al. (5 more authors) (2017) Evaluation of a low-cost optical particle counter (Alphasense OPC-N2) for ambient air monitoring. Atmospheric Measurement Techniques Discussions. ISSN 1867-8610
Abstract
A fast growing area of research is the development of low-cost sensors for measuring air pollutants. The affordability and size of low-cost particle sensors makes them an attractive option for use in experiments requiring a number of instruments such as high density spatial mapping. However, for these low-cost sensors to be useful for these types of studies their accuracy and precision needs to be quantified. We evaluated the Alphasense OPC-N2, a promising low-cost miniature optical particle counter, for monitoring ambient airborne particles at typical urban background sites in the UK. The precision of the OPC-N2 was assessed by co-locating 14 instruments at a site to investigate the variation in measured concentrations. Comparison to two different reference optical particle counters as well as a TEOM-FDMS enabled the accuracy of the OPC-N2 to be evaluated. Comparison of the OPC-N2 to the reference optical instruments demonstrated reasonable agreement for the measured mass concentrations of PM1, PM2.5 and PM10. However, the OPC-N2 demonstrated a significant positive artefact in measured particle mass during times of high ambient RH (> 85 %) and a calibration factor was developed based upon κ-Kohler theory, using average bulk particle aerosol hygroscopicity. Application of this RH correction factor resulted in the OPC-N2 measurements being within 33 % of the TEOM-FDMS, comparable to the agreement between a reference optical particle counter and the TEOM-FDMS (20 %). Reasonable inter-unit precision for the 14 OPC-N2 sensors was observed. Overall, the OPC-N2 was found to accurately measure ambient airborne particle mass concentration provided they are i) correctly calibrated and ii) corrected for ambient RH. The reasonable level of precision demonstrated between multiple OPC-N2 suggests that they would be suitable device for applications where the spatial variability in particle concentration was to be determined.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | ©Author(s) 2017. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Funding Information: | Funder Grant number NATURAL ENVIRONMENT RESEARCH COUNCIL NE/F015240/1 NATURAL ENVIRONMENT RESEARCH COUNCIL NE/M021513/1 |
Depositing User: | Pure (York) |
Date Deposited: | 02 Jan 2018 13:10 |
Last Modified: | 25 Nov 2024 00:29 |
Published Version: | https://doi.org/10.5194/amt-2017-308 |
Status: | Published |
Refereed: | No |
Identification Number: | 10.5194/amt-2017-308 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:125675 |