{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T09:46:03Z","timestamp":1777974363894,"version":"3.51.4"},"reference-count":56,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2020,11,5]],"date-time":"2020-11-05T00:00:00Z","timestamp":1604534400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Office of Biological and Environmental Research of the US Department of Energy","award":["DE-A06-76RLO 1830"],"award-info":[{"award-number":["DE-A06-76RLO 1830"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Accurate representation of atmospheric aerosol properties is a long-standing problem in atmospheric research. Modern pilotless aerial systems provide a new platform for atmospheric in situ measurement. However, small airborne platforms require miniaturized instrumentation due to apparent size, power, and weight limitations. A Portable Optical Particle Spectrometer (POPS) is an emerged instrument to measure ambient aerosol size distribution with high time and size resolution, designed for deployment on a small unmanned aerial system (UAS) or tethered balloon system (TBS) platforms. This study evaluates the performance of a POPS with an upgraded laser heater and additional temperature sensors in the aerosol pathway. POPS maintains its performance under different environmental conditions as long as the laser temperature remains above 25 \u00b0C and the aerosol flow temperature inside the optical chamber is 15 \u00b0C higher than the ambient temperature. The comparison between POPS and an Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) suggests that the coincidence error is less than 25% when the number concentration is less than 4000 cm\u22123. The size distributions measured by both of them remained unaffected up to 15,000 cm\u22123. While both instruments\u2019 sizing accuracy is affected by the aerosol chemical composition and morphology, the influence is more profound on the POPS.<\/jats:p>","DOI":"10.3390\/s20216294","type":"journal-article","created":{"date-parts":[[2020,11,5]],"date-time":"2020-11-05T09:04:34Z","timestamp":1604567074000},"page":"6294","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["Performance Assessment of Portable Optical Particle Spectrometer (POPS)"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4285-2749","authenticated-orcid":false,"given":"Fan","family":"Mei","sequence":"first","affiliation":[{"name":"Pacific Northwest National Laboratory, Richland, WA 99352, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gavin","family":"McMeeking","sequence":"additional","affiliation":[{"name":"Handix Scientific LLC, Boulder, CO 80301, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9821-0078","authenticated-orcid":false,"given":"Mikhail","family":"Pekour","sequence":"additional","affiliation":[{"name":"Pacific Northwest National Laboratory, Richland, WA 99352, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ru-Shan","family":"Gao","sequence":"additional","affiliation":[{"name":"NOAA Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO 80305, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8069-4281","authenticated-orcid":false,"given":"Gourihar","family":"Kulkarni","sequence":"additional","affiliation":[{"name":"Pacific Northwest National Laboratory, Richland, WA 99352, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7670-335X","authenticated-orcid":false,"given":"Swarup","family":"China","sequence":"additional","affiliation":[{"name":"Pacific Northwest National Laboratory, Richland, WA 99352, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hagen","family":"Telg","sequence":"additional","affiliation":[{"name":"Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Darielle","family":"Dexheimer","sequence":"additional","affiliation":[{"name":"Sandia National Laboratories, Albuquerque, NM 87185, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0734-3298","authenticated-orcid":false,"given":"Jason","family":"Tomlinson","sequence":"additional","affiliation":[{"name":"Pacific Northwest National Laboratory, Richland, WA 99352, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4705-8715","authenticated-orcid":false,"given":"Beat","family":"Schmid","sequence":"additional","affiliation":[{"name":"Pacific Northwest National Laboratory, Richland, WA 99352, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1327","DOI":"10.3390\/atmos6091327","article-title":"An Overview of Particulate Matter Measurement Instruments","volume":"6","author":"Amaral","year":"2015","journal-title":"Atmosphere"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"715","DOI":"10.5194\/acp-5-715-2005","article-title":"Global indirect aerosol effects: A review","volume":"5","author":"Lohmann","year":"2005","journal-title":"Atmos. 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