pass: Photoacoustic Soot Spectrometer

The photoacoustic soot spectrometer (PASS) measures light absorption by aerosol particles. As the particles pass through a laser beam, the absorbed energy heats the particles and in turn the surrounding air, which sets off a pressure wave that can be detected by a microphone.

The PASS instruments can also simultaneously measure the scattered laser-light at three wavelengths and therefore provide a direct measure of the single scattering albedo.

The PASS is part of the Aerosol Observing System (AOS).



  • Fixed
  • AMF1
  • AMF2
  • AMF3

Related Publications


Forestieri S, T Helgestad, A Lambe, L Renbaum-Wolff, D Lack, P Massoli, E Cross, M Dubey, C Mazzoleni, J Olfert, A Sedlacek III, A Freedman, P Davidovits, T Onasch, and C Cappa. 2018. "Measurement and modeling of the multiwavelength optical properties of uncoated flame-generated soot." Atmospheric Chemistry and Physics, 18(16), 10.5194/acp-18-12141-2018.

Sheesley RJ, R Subramanian, C Flynn, M Dubey, N Hickmon, and S Yoon. 2018. Absorption at San Antonio with 3-Wavelength Photoacoustic Soot Spectrometer, Tricolor Absorption Photometer (ASAPT) Field Campaign Report. Ed. by Robert Stafford, ARM Climate Research Facility. DOE/SC-ARM-18-003.


Dubey M, A Aiken, LK Berg, A Freedman, and K Gorkowski. 2016. Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report. Ed. by Robert Stafford, DOE ARM Climate Research Facility. DOE/SC-ARM-16-047.


Schmid B, JM Tomlinson, JM Hubbe, JM Comstock, F Mei, D Chand, MS Pekour, CD Kluzek, E Andrews, SC Biraud, and GM McFarquhar. 2014. "The DOE ARM Aerial Facility." Bulletin of the American Meteorological Society, 95(5), 10.1175/bams-d-13-00040.1.


Hiranuma N, SD Brooks, RC Moffet, A Glen, A Laskin, MK Gilles, P Liu, AM Macdonald, JW Strapp, and GM McFarquhar. 2013. "Chemical characterization of individual particles and residuals of cloud droplets and ice crystals collected on board research aircraft in the ISDAC 2008 study." Journal of Geophysical Research: Atmospheres, 118(12), 10.1002/jgrd.50484.
Research Highlight

Aiken A, M Dubey, and S Liu. 2013. PASS3 Measurements from Two DOE ARM Aerosol Observing Systems (AOS): SGP and the Recent MAOS Deployments for PACE and TCAP. Presented at 4th Atmospheric System Research (ASR) Science Team Meeting. Potomac, MD.

Aiken A. 2013. Photoacoustic Soot Spectrometer (PASS) Handbook. U.S. Department of Energy. DOE/SC-ARM-TR-123.


Zaveri RA, WJ Shaw, DJ Cziczo, B Schmid, RA Ferrare, ML Alexander, M Alexandrov, RJ Alvarez, WP Arnott, DB Atkinson, S Baidar, RM Banta, JC Barnard, J Beranek, LK Berg, F Brechtel, WA Brewer, JF Cahill, B Cairns, CD Cappa, D Chand, S China, JM Comstock, MK Dubey, RC Easter, MH Erickson, JD Fast, C Floerchinger, BA Flowers, E Fortner, JS Gaffney, MK Gilles, K Gorkowski, WI Gustafson, M Gyawali, J Hair, RM Hardesty, RW Harworth, S Herndon, N Hiranuma, C Hostetler, JM Hubbe, JT Jayne, H Jeong, BT Jobson, EI Kassianov, LI Kleinman, C Kluzek, B Knighton, KR Kolesar, C Kuang, A Kubatova, AO Langford, A Laskin, N Laulainen, RD Marchbanks, C Mazzoleni, F Mei, RC Moffet, D Nelson, MD Obland, H Oetjen, TB Onasch, I Ortega, M Ottaviani, M Pekour, KA Prather, JG Radney, RR Rogers, SP Sandberg, A Sedlacek, CJ Senff, G Senum, A Setyan, JE Shilling, M Shrivastava, C Song, SR Springston, R Subramanian, K Suski, J Tomlinson, R Volkamer, HW Wallace, J Wang, AM Weickmann, DR Worsnop, XY Yu, A Zelenyuk, and Q Zhang. 2012. "Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)." Atmospheric Chemistry and Physics, 12(16), 10.5194/acp-12-7647-2012.

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