Oral Presentation Only

Modifying and Calibrating Low-Cost Optical Particle Counters for Stratospheric Ballooning Use

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Abstract

   Optical particle counters (OPCs) use the scattering of a laser beam to count micron and sub-micron size particulates in air flow and to classify particles into size bins. OPCs are used in commercial applications ranging from smoke detectors to pollution monitors. On stratospheric balloon flights, OPCs can be used to characterize particulate content in the atmosphere as a function of altitude, geographic location, weather/season, and more. Unfortunately most OPCs are not calibrated for, and some cannot even operate in, the low pressure and low temperature conditions of the stratosphere.
   One state-of-the-art OPC, the Light Optical Aerosol Counter (LOAC) sold by MeteoModem, comes in a fan-based “recorder” version for surface applications, like pollution monitoring, and a pump-based “telemetry” version that is capable of making measurements in stratospheric conditions. However at ~$10K per unit, the LOAC is too expensive for most academic ballooning teams to adopt.
   Inspired by the LOAC telemetry unit, coupled with tips gleaned from presentations delivered at past AHACs by teams using much-lower-cost OPCs to make particulate measurements on tropospheric and stratospheric balloon missions, we have been conducting ground calibration and stratospheric flight testing of a several low-cost OPCs including the Plantower 5003 (<$50), the Sensirion SPS30 (<$50), and the AlphaSense N3 (<$500). Preliminary results suggest that it is possible to retrofit at least some low-cost OPCs with pumps, allowing them to get adequate airflow even in the rarified conditions of the stratosphere to count and classify particles by size. Comparison of low-cost OPCs with well-calibrated (but non-flyable) control OPCs in the lab suggest that recalibration under extreme/stratospheric conditions is indeed possible, potentially opening the way to significantly reduce the cost of making stratospheric particulate measurements (at least as compared to using LOAC and other high-cost OPCs).

Keywords: stratospheric ballooning, ostratospheric ballooning, optical particle counter, OPC

How to Cite:

Pharis, N., Habeck, J., Douglas, J., Meiners, J., Ally, A., Collins, P. & Flaten, J., (2022) “Modifying and Calibrating Low-Cost Optical Particle Counters for Stratospheric Ballooning Use”, Academic High Altitude Conference 2020(1). doi: https://doi.org/10.31274/ahac.11650