A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance
<p>There exists a lack of aerosol absorption measurement techniques with low uncertainties and without artefacts. We have developed the two-wavelength Photothermal Aerosol Absorption Monitor (PTAAM-<span class="inline-formula">2<i>λ</i>)</span>, which measures...
| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-06-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/15/3805/2022/amt-15-3805-2022.pdf |
| _version_ | 1811334201617678336 |
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| author | L. Drinovec L. Drinovec L. Drinovec U. Jagodič U. Jagodič L. Pirker L. Pirker M. Škarabot M. Kurtjak K. Vidović L. Ferrero B. Visser J. Röhrbein E. Weingartner D. M. Kalbermatter K. Vasilatou T. Bühlmann C. Pascale T. Müller A. Wiedensohler G. Močnik G. Močnik G. Močnik |
| author_facet | L. Drinovec L. Drinovec L. Drinovec U. Jagodič U. Jagodič L. Pirker L. Pirker M. Škarabot M. Kurtjak K. Vidović L. Ferrero B. Visser J. Röhrbein E. Weingartner D. M. Kalbermatter K. Vasilatou T. Bühlmann C. Pascale T. Müller A. Wiedensohler G. Močnik G. Močnik G. Močnik |
| author_sort | L. Drinovec |
| collection | DOAJ |
| description | <p>There exists a lack of aerosol absorption measurement techniques with low
uncertainties and without artefacts. We have developed the two-wavelength
Photothermal Aerosol Absorption Monitor (PTAAM-<span class="inline-formula">2<i>λ</i>)</span>, which measures
the aerosol absorption coefficient at 532 and 1064 nm. Here we describe its design, calibration and mode of operation and evaluate its applicability, limits and uncertainties. The 532 nm channel was calibrated with <span class="inline-formula">∼</span> 1 <span class="inline-formula">µmol</span> mol<span class="inline-formula"><sup>−1</sup></span> NO<span class="inline-formula"><sub>2</sub></span>, whereas the 1064 nm channel was
calibrated using measured size distribution spectra of nigrosin particles
and a Mie calculation. Since the aerosolized nigrosin used for calibration
was dry, we determined the imaginary part of the refractive index of
nigrosin from the absorbance measurements on solid thin film samples. The
obtained refractive index differed considerably from the one determined
using aqueous nigrosin solution. PTAAM-2<span class="inline-formula"><i>λ</i></span> has no scattering
artefact and features very low uncertainties: 4 % and 6 % for the
absorption coefficient at 532 and 1064 nm, respectively, and 9 % for the
absorption Ångström exponent. The artefact-free nature of the
measurement method allowed us to investigate the artefacts of filter
photometers. Both the Aethalometer AE33 and CLAP suffer from
cross-sensitivity to scattering – this scattering artefact is most
pronounced for particles smaller than 70 nm. We observed a strong dependence
of the filter multiple scattering parameter on the particle size in the
100–500 nm range. The results from the winter ambient campaign in Ljubljana
showed similar multiple scattering parameter values for ambient aerosols and
laboratory experiments. The spectral dependence of this parameter resulted
in AE33 reporting the absorption Ångström exponent for different
soot samples with values biased 0.23–0.35 higher than the PTAAM-2<span class="inline-formula"><i>λ</i></span> measurement. Photothermal interferometry is a promising method for reference
aerosol absorption measurements.</p> |
| first_indexed | 2024-04-13T17:04:26Z |
| format | Article |
| id | doaj.art-98f65ecf1c11458688ebfe60afdad7b8 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-13T17:04:26Z |
| publishDate | 2022-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-98f65ecf1c11458688ebfe60afdad7b82022-12-22T02:38:31ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482022-06-01153805382510.5194/amt-15-3805-2022A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performanceL. Drinovec0L. Drinovec1L. Drinovec2U. Jagodič3U. Jagodič4L. Pirker5L. Pirker6M. Škarabot7M. Kurtjak8K. Vidović9L. Ferrero10B. Visser11J. Röhrbein12E. Weingartner13D. M. Kalbermatter14K. Vasilatou15T. Bühlmann16C. Pascale17T. Müller18A. Wiedensohler19G. Močnik20G. Močnik21G. Močnik22Haze Instruments d.o.o., Ljubljana, SloveniaDepartment of Condensed Matter Physics, Jozef Stefan Institute, Ljubljana, SloveniaCenter for Atmospheric Research, University of Nova Gorica, Nova Gorica, SloveniaHaze Instruments d.o.o., Ljubljana, SloveniaDepartment of Condensed Matter Physics, Jozef Stefan Institute, Ljubljana, SloveniaDepartment of Condensed Matter Physics, Jozef Stefan Institute, Ljubljana, SloveniaFaculty for Mathematics and Physics, University of Ljubljana, Ljubljana, SloveniaDepartment of Condensed Matter Physics, Jozef Stefan Institute, Ljubljana, SloveniaAdvanced Materials Department, Jozef Stefan Institute, Ljubljana, SloveniaDepartment for Analytical Chemistry, National Institute of Chemistry, Ljubljana, SloveniaGEMMA Center, University of Milano-Bicocca, Milan, ItalyInstitute for Sensors and Electronics, University of Applied Sciences Northwestern Switzerland, Windisch, SwitzerlandInstitute for Sensors and Electronics, University of Applied Sciences Northwestern Switzerland, Windisch, SwitzerlandInstitute for Sensors and Electronics, University of Applied Sciences Northwestern Switzerland, Windisch, SwitzerlandFederal Institute of Metrology METAS, Bern, SwitzerlandFederal Institute of Metrology METAS, Bern, SwitzerlandFederal Institute of Metrology METAS, Bern, SwitzerlandFederal Institute of Metrology METAS, Bern, SwitzerlandExperimental Aerosol & Cloud Microphysics, Leibniz Institute for Tropospheric Research, Leipzig, GermanyExperimental Aerosol & Cloud Microphysics, Leibniz Institute for Tropospheric Research, Leipzig, GermanyHaze Instruments d.o.o., Ljubljana, SloveniaDepartment of Condensed Matter Physics, Jozef Stefan Institute, Ljubljana, SloveniaCenter for Atmospheric Research, University of Nova Gorica, Nova Gorica, Slovenia<p>There exists a lack of aerosol absorption measurement techniques with low uncertainties and without artefacts. We have developed the two-wavelength Photothermal Aerosol Absorption Monitor (PTAAM-<span class="inline-formula">2<i>λ</i>)</span>, which measures the aerosol absorption coefficient at 532 and 1064 nm. Here we describe its design, calibration and mode of operation and evaluate its applicability, limits and uncertainties. The 532 nm channel was calibrated with <span class="inline-formula">∼</span> 1 <span class="inline-formula">µmol</span> mol<span class="inline-formula"><sup>−1</sup></span> NO<span class="inline-formula"><sub>2</sub></span>, whereas the 1064 nm channel was calibrated using measured size distribution spectra of nigrosin particles and a Mie calculation. Since the aerosolized nigrosin used for calibration was dry, we determined the imaginary part of the refractive index of nigrosin from the absorbance measurements on solid thin film samples. The obtained refractive index differed considerably from the one determined using aqueous nigrosin solution. PTAAM-2<span class="inline-formula"><i>λ</i></span> has no scattering artefact and features very low uncertainties: 4 % and 6 % for the absorption coefficient at 532 and 1064 nm, respectively, and 9 % for the absorption Ångström exponent. The artefact-free nature of the measurement method allowed us to investigate the artefacts of filter photometers. Both the Aethalometer AE33 and CLAP suffer from cross-sensitivity to scattering – this scattering artefact is most pronounced for particles smaller than 70 nm. We observed a strong dependence of the filter multiple scattering parameter on the particle size in the 100–500 nm range. The results from the winter ambient campaign in Ljubljana showed similar multiple scattering parameter values for ambient aerosols and laboratory experiments. The spectral dependence of this parameter resulted in AE33 reporting the absorption Ångström exponent for different soot samples with values biased 0.23–0.35 higher than the PTAAM-2<span class="inline-formula"><i>λ</i></span> measurement. Photothermal interferometry is a promising method for reference aerosol absorption measurements.</p>https://amt.copernicus.org/articles/15/3805/2022/amt-15-3805-2022.pdf |
| spellingShingle | L. Drinovec L. Drinovec L. Drinovec U. Jagodič U. Jagodič L. Pirker L. Pirker M. Škarabot M. Kurtjak K. Vidović L. Ferrero B. Visser J. Röhrbein E. Weingartner D. M. Kalbermatter K. Vasilatou T. Bühlmann C. Pascale T. Müller A. Wiedensohler G. Močnik G. Močnik G. Močnik A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance Atmospheric Measurement Techniques |
| title | A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance |
| title_full | A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance |
| title_fullStr | A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance |
| title_full_unstemmed | A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance |
| title_short | A dual-wavelength photothermal aerosol absorption monitor: design, calibration and performance |
| title_sort | dual wavelength photothermal aerosol absorption monitor design calibration and performance |
| url | https://amt.copernicus.org/articles/15/3805/2022/amt-15-3805-2022.pdf |
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