scholarly journals Characterizing the performance of a POPS miniaturized optical particle counter when operated on a quadcopter drone

2021 ◽  
Author(s):  
Zixia Liu ◽  
Martin Osborne ◽  
Jim Haywood ◽  
Karen Anderson ◽  
Jamie D. Shulter ◽  
...  
Keyword(s):  
Wind Speed ◽  
Low Cost ◽  
Aerosol Particles ◽  
High Sensitivity ◽  
Absolute Difference ◽  
Size Distributions ◽  
Scanning Mobility Particle Sizer ◽  
Particle Counter ◽  
Optical Particle Counter ◽  
The Impact

Abstract. The Printed Optical Particle Spectrometer (POPS) is an advanced and small low-cost, light-weight, and high-sensitivity optical particle counter (OPC), particularly designed for deployed on unpiloted aerial vehicles (UAVs) and balloon sondes. We report the performance of the POPS against a reference scanning mobility particle sizer (SMPS) and an airborne passive cavity aerosol spectrometer probe (PCASP) while the POPS is operated on the ground and also while operated on a quadcopter drone, a DJI Matrice 200 V2. This is the first such documented test of the performance of a POPS instrument on a UAV. We investigate the root mean square difference (RMSD) and mean absolute difference (MAD) in particle number concentrations (PNCs) when operating on the ground and on the Matrice 200. When windspeeds are less than 2.6 m/s, we find only modest differences in the RMSDs and MADs of 2.4 % and 2.3 % respectively when operating on the ground, and to 5 % and 3 % when operating at 10m altitude. When windspeeds are greater than 2.6 m/s but less than 7.7 m/s the RMSDs and MADs increase to 10.2 % and 7.8 % respectively when operating on the ground, and 26.2 % and 19.1 %, respectively when operating at 10m altitude. No statistical difference in PNCs was detected when operating on the UAV in either ascent or descent. We also find size distributions of aerosols in the accumulation mode (here defined by diameter, d, where 0.1 ≤ d ≤ 1 µm) are relatively consistent between measurements at the surface and measurements at 10m altitude with RMSD and MAD of less than 21.6 % and 15.7 %, respectively. However, the differences between coarse mode (here defined by d > 1 µm) are universally larger than those measured at the surface with a RMSD and MAD approaching 49.5 % and 40.4 %. Our results suggest that the impact of the UAV rotors on the POPS does not unduly affect the performance of the POPS for wind speed less than 2.6 m/s, but when operating under higher wind speed of up to 7.6 m/s, larger discrepancies are noted. In addition to this, it appears that the POPS measures sub-micron aerosol particles more accurately than super-micron aerosol particles when airborne on the UAV. These measurements lay the foundations for determining the magnitude of potential errors that might be introduced into measured aerosol particle size distributions and concentrations owing to the turbulence created by the rotors on the UAV.

scholarly journals Characterizing the performance of a POPS miniaturized optical particle counter when operated on a quadcopter drone

2021 ◽  
Vol 14 (9) ◽  
pp. 6101-6118
Author(s):  
Zixia Liu ◽  
Martin Osborne ◽  
Karen Anderson ◽  
Jamie D. Shutler ◽  
Andy Wilson ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
High Sensitivity ◽  
Absolute Difference ◽  
Size Distributions ◽  
Scanning Mobility Particle Sizer ◽  
Particle Counter ◽  
Wind Speeds ◽  
Optical Particle Counter ◽  
Aerosol Particle Size ◽  
The Impact

Abstract. We first validate the performance of the Portable Optical Particle Spectrometer (POPS), a small light-weight and high sensitivity optical particle counter, against a reference scanning mobility particle sizer (SMPS) for a month-long deployment in an environment dominated by biomass burning aerosols. Subsequently, we examine any biases introduced by operating the POPS on a quadcopter drone, a DJI Matrice 200 V2. We report the root mean square difference (RMSD) and mean absolute difference (MAD) in particle number concentrations (PNCs) when mounted on the UAV and operating on the ground and when hovering at 10 m. When wind speeds are low (less than 2.6 m s−1), we find only modest differences in the RMSDs and MADs of 5 % and 3 % when operating at 10 m altitude. When wind speeds are between 2.6 and 7.7 m s−1 the RMSDs and MADs increase to 26.2 % and 19.1 %, respectively, when operating at 10 m altitude. No statistical difference in PNCs was detected when operating on the UAV in either ascent or descent. We also find size distributions of aerosols in the accumulation mode (defined by diameter, d, where 0.1 ≤ d ≤ 1 µm) are relatively consistent between measurements at the surface and measurements at 10 m altitude, while differences in the coarse mode (here defined by d >  1 µm) are universally larger. Our results suggest that the impact of the UAV rotors on the POPS PNCs are small at low wind speeds, but when operating under a higher wind speed of up to 7.6 m s−1, larger discrepancies occur. In addition, it appears that the POPS measures sub-micron aerosol particles more accurately than super-micron aerosol particles when airborne on the UAV. These measurements lay the foundations for determining the magnitude of potential errors that might be introduced into measured aerosol particle size distributions and concentrations owing to the turbulence created by the rotors on the UAV.

scholarly journals The Universal Cloud and Aerosol Sounding System (UCASS): a low-cost miniature optical particle counter for use in dropsonde or balloon-borne sounding systems

2019 ◽  
Author(s):  
Helen R. Smith ◽  
Zbigniew Ulanowski ◽  
Paul H. Kaye ◽  
Edwin Hirst ◽  
Warren Stanley ◽  
...  
Keyword(s):  
Low Cost ◽  
Air Flow ◽  
Size Distributions ◽  
Elastic Light Scattering ◽  
Particle Counter ◽  
Optical Particle Counter ◽  
Aerial Vehicle ◽  
Comparative Results ◽  
Sd Card ◽  
The University

Abstract. A low-cost miniaturized particle counter has been developed by The University of Hertfordshire (UH) for the measurement of aerosol/droplet concentrations and size distributions. The Universal Cloud and Aerosol Sounding System (UCASS)is an Optical Particle Counter (OPC), which uses wide-angle elastic light scattering for the high precision sizing of fluid-borne particulates. The UCASS has up to 16 configurable size bins, capable of sizing particles in the range 0.4–40 micrometer in diameter. Unlike traditional particle counters, the UCASS is an open-geometry system which relies on an external air flow. Therefore the instrument is suited for use as part of a dropsonde, balloon-borne sounding system, as part of an Unmanned Aerial Vehicle (UAV), or on any measurement platform with a known air flow. Data can be logged autonomously using an on-board SD card,or the device can be interfaced with commercially available meteorological sondes to transmit data in real time. The device has been deployed on various research platforms to take measurements of both droplets and dry aerosol particles. Comparative results with co-located instrumentation in both laboratory and field settings are used to assess the performance of the UCASS.

A High-Sensitivity Low-Cost Optical Particle Counter Design

2013 ◽  
Vol 47 (2) ◽  
pp. 137-145 ◽  
Author(s):  
R. S. Gao ◽  
A. E. Perring ◽  
T. D. Thornberry ◽  
A. W. Rollins ◽  
J. P. Schwarz ◽  
...  
Keyword(s):  
Low Cost ◽  
High Sensitivity ◽  
Particle Counter ◽  
Optical Particle Counter

scholarly journals Evaluation of a low-cost optical particle counter (Alphasense OPC-N2) for ambient air monitoring

2018 ◽  
Vol 11 (2) ◽  
pp. 709-720 ◽  
Author(s):  
Leigh R. Crilley ◽  
Marvin Shaw ◽  
Ryan Pound ◽  
Louisa J. Kramer ◽  
Robin Price ◽  
...  
Keyword(s):  
Low Cost ◽  
Ambient Air ◽  
Particle Mass ◽  
Particle Counter ◽  
Optical Particle Counter ◽  
Attractive Option ◽  
Kohler Theory ◽  
Pm2.5 And Pm10 ◽  
The Uk ◽  
Mass Concentrations

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 need 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 shows some limitations for measuring mass concentrations of PM1, PM2.5 and PM10. 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-Köhler 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 %). Inter-unit precision for the 14 OPC-N2 sensors of 22 ± 13 % for PM10 mass concentrations 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 level of precision demonstrated between multiple OPC-N2s suggests that they would be suitable devices for applications where the spatial variability in particle concentration was to be determined.

scholarly journals Design and Field Campaign Validation of a Multirotor UAV and Optical Particle Counter

2020 ◽  
Author(s):  
Joseph Girdwood ◽  
Helen Smith ◽  
Warren Stanley ◽  
Zbigniew Ulanowski ◽  
Chris Stopford ◽  
...  
Keyword(s):  
Low Cost ◽  
Unmanned Aircraft ◽  
Coefficient Of Determination ◽  
Sampling System ◽  
Particle Counter ◽  
Representative Sampling ◽  
Atmospheric Particulates ◽  
Optical Particle Counter ◽  
Good Agreement

Abstract. Small unmanned aircraft (SUA) have the potential to be used as platforms for the measurement of atmospheric particulates. The use of an SUA platform for these measurements provides benefits such as high manoeuvrability, re-usability, and low-cost when compared with traditional techniques. However, the complex aerodynamics of an SUA (particularly for multirotor airframes), combined with the miniaturisation of particle instruments poses difficulties for accurate and representative sampling of particulates. The work presented here relies on computational fluid dynamics with Lagrangian particle tracking (CFD-LPT) simulations to influence the design of a bespoke meteorological sampling system: the UH-AeroSAM. This consists of a custom built airframe, designed to reduce sampling artefacts due to the propellers, and a purpose built open-path optical particle counter–the Ruggedised Cloud and Aerosol Sounding System (RCASS). OPC size distribution measurements from the UH-AeroSAM are compared with the Cloud and Aerosol Precipitation Spectrometer (CAPS) for measurements of Stratus cloud during the Pallas Cloud Experiment (PaCE) in 2019. Good agreement is demonstrated between the two instruments. The integrated dN/dlog(Dp) is shown to have a coefficient of determination of 0.8, and a regression slope of 0.9 when plotted 1:1.

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