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Comparing black-carbon- and aerosol-absorption-measuring instruments – a new system using lab-generated soot coated with controlled amounts of secondary organic matter
Antti-Pekka Hyvärinen, Konstantina Vasilatou, Matthias Oscity, Ernest Weingartner, Bradley Visser, Jannis Röhrbein, Luka Drinovec, Daniel M. Kalbermatter, Griša Močnik, 2022, original scientific article

Abstract: We report on an inter-comparison of black-carbon- and aerosol-absorption-measuring instruments with laboratory-generated soot particles coated with controlled amounts of secondary organic matter (SOM). The aerosol generation setup consisted of a miniCAST 5201 Type BC burner for the generation of soot particles and a new automated oxidation flow reactor based on the micro smog chamber (MSC) for the generation of SOM from the ozonolysis of α-pinene. A series of test aerosols was generated with elemental to total carbon (EC  TC) mass fraction ranging from about 90 % down to 10 % and single-scattering albedo (SSA at 637 nm) from almost 0 to about 0.7. A dual-spot Aethalometer AE33, a photoacoustic extinctiometer (PAX, 870 nm), a multi-angle absorption photometer (MAAP), a prototype photoacoustic instrument, and two prototype photo-thermal interferometers (PTAAM-2λ and MSPTI) were exposed to the test aerosols in parallel. Significant deviations in the response of the instruments were observed depending on the amount of secondary organic coating. We believe that the setup and methodology described in this study can easily be standardised and provide a straightforward and reproducible procedure for the inter-comparison and characterisation of both filter-based and in situ black-carbon-measuring (BC-measuring) instruments based on realistic test aerosols.
Found in: ključnih besedah
Keywords: black carbon, aerosol absorption, secondary organic aerosol, coating
Published: 01.02.2022; Views: 454; Downloads: 12
.pdf Fulltext (752,94 KB)

The impact of temperature inversions on black carbon and particle mass concentrations in a mountainous area
Miha Markelj, Maja Remškar, Martin Rigler, Irena Ježek, Kay Weinhold, Matej Ogrin, Asta Gregorič, Luka Drinovec, Andrea Cuesta-Mosquera, Honey Dawn C. Alas, Kristina Glojek, Griša Močnik, 2022, original scientific article

Abstract: Residential wood combustion is a widespread practice in Europe with a serious impact on air quality, especially in mountainous areas. While there is a significant number of studies conducted in deep urbanized valleys and basins, little is known about the air pollution processes in rural shallow hollows, where around 30 % of the people in mountainous areas across Europe live. We aim to determine the influence of ground temperature inversions on wood combustion aerosol pollution in hilly, rural areas. The study uses Retje karst hollow (Loški Potok, Slovenia) as a representative site for mountainous and hilly rural areas in central and south-eastern Europe with residential wood combustion. Sampling with a mobile monitoring platform along the hollow was performed in December 2017 and January 2018. The backpack mobile monitoring platform was used for the determination of equivalent black carbon (eBC) and particulate matter (PM) mass concentrations along the hollow. To ensure high quality of mobile measurement data, intercomparisons of mobile instruments with reference instruments were performed at two air quality stations during every run. Our study showed that aerosol pollution events in the relief depression were associated with high local emission intensities originating almost entirely from residential wood burning and shallow temperature inversions (58 m on average). The eBC and PM mass concentrations showed stronger associations with the potential temperature gradient (R2=0.8) than with any other meteorological parameters taken into account (ambient temperature, relative humidity, wind speed, wind direction, and precipitation). The strong association between the potential temperature gradient and pollutant concentrations suggests that even a small number of emission sources (total 243 households in the studied hollow) in similar hilly and mountainous rural areas with frequent temperature inversions can significantly increase the levels of eBC and PM and deteriorate local air quality. During temperature inversions the measured mean eBC and PM2.5 mass concentrations in the whole hollow were as high as 4.5±2.6 and 48.0 ± 27.7 µg m−3, respectively, which is comparable to larger European urban centres.
Found in: ključnih besedah
Keywords: air pollution, black carbon, sources, temperature inversion, mountainous area
Published: 03.05.2022; Views: 217; Downloads: 0
.pdf Fulltext (7,11 MB)

Siberian Arctic black carbon
Nikolay S. Kasimov, Marina A. Chichaeva, Konstantinos Eleftheriadis, Asta Gregorič, Vasilii O. Kobelev, Nikolaos Evangeliou, Olga B. Popovicheva, 2022, original scientific article

Found in: ključnih besedah
Keywords: black carbon, Arctic, gas flaring, wildfire
Published: 09.05.2022; Views: 223; Downloads: 0
.pdf Fulltext (10,16 MB)

European Aerosol Phenomenology - 8: Harmonised Source Apportionment of Organic Aerosol using 22 Year-long ACSM/AMS Datasets
Gang Chen, Francesco Canonaco, Anna Tobler, Griša Močnik, MaríaCruz Minguillón, André Prévôt, 2022, original scientific article

Abstract: Organic aerosol (OA) is a key component to total submicron particulate matter (PM1), and comprehensive knowledge of OA sources across Europe is crucial to mitigate PM1 levels. Europe has a well-established air quality research infrastructure from which yearlong datasets using 21 aerosol chemical speciation monitors (ACSMs) and 1 aerosol mass spectrometer (AMS) were gathered during 2013-2019. It includes 9 non-urban and 13 urban sites. This study developed a state-of-the-art source apportionment protocol to analyse long-term OA mass spectrum data by applying the most advanced source apportionment strategies (i.e., rolling PMF, ME-2, and bootstrap). This harmonised protocol was followed strictly for all 22 datasets, making the source apportionment results more comparable. In addition, it enables the quantifications of the most common OA components such as hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking-like OA (COA), more oxidised-oxygenated OA (MO-OOA), and less oxidised-oxygenated OA (LO-OOA). Other components such as coal combustion OA (CCOA), solid fuel OA (SFOA: mainly mixture of coal and peat combustion), cigarette smoke OA (CSOA), sea salt (mostly inorganic but part of the OA mass spectrum), coffee OA, and ship industry OA could also be separated at a few specific sites. Oxygenated OA (OOA) components make up most of the submicron OA mass (average = 71.1%, range from 43.7 to 100%). Solid fuel combustion-related OA components (i.e., BBOA, CCOA, and SFOA) are still considerable with in total 16.0% yearly contribution to the OA, yet mainly during winter months (21.4%). Overall, this comprehensive protocol works effectively across all sites governed by different sources and generates robust and consistent source apportionment results. Our work presents a comprehensive overview of OA sources in Europe with a unique combination of high time resolution (30-240 minutes) and long-term data coverage (9-36 months), providing essential information to improve/validate air quality, health impact, and climate models.
Found in: ključnih besedah
Summary of found: ...air pollution, source apportionment, organic aeroosl, black carbon...
Keywords: air pollution, source apportionment, organic aeroosl, black carbon
Published: 03.06.2022; Views: 165; Downloads: 1
.pdf Fulltext (4,69 MB)
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A dual-wavelength photothermal aerosol absorption monitor
Konstantina Vasilatou, Griša Močnik, Ernest Weingartner, Daniel M. Kalbermatter, Bradley Visser, Jannis Röhrbein, Luca Ferrero, Kristijan Vidović, Mario Kurtjak, Miha Škarabot, Luka Pirker, Luka Drinovec, Uroš Jagodič, 2022, original scientific article

Abstract: 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-2λ), 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 ∼ 1 µmol mol−1 NO2, 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-2λ 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-2λ measurement. Photothermal interferometry is a promising method for reference aerosol absorption measurements.
Found in: ključnih besedah
Summary of found: ...aerosol absorption, calibration, black carbon...
Keywords: aerosol absorption, calibration, black carbon
Published: 28.06.2022; Views: 112; Downloads: 3
.pdf Fulltext (2,90 MB)
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Measuring the Aerosol Light Absorption Coefficient - a Not-So-Easy Task With Relevance for the Global and Regional Climate
Griša Močnik, 2022, unpublished invited conference lecture

Abstract: The photothermal interferometer measurement of aerosol absorption, using pump lasers (532, 1064 nm) and phase sensitive detection results in 4 and 6% measurement uncertainty. It is calibrated traceably to primary standards and thereby a potential reference.
Found in: ključnih besedah
Summary of found: ...aerosol absorption, black carbon, climate change...
Keywords: aerosol absorption, black carbon, climate change
Published: 20.07.2022; Views: 111; Downloads: 0
.pdf Fulltext (2,58 MB)

Measuring aerosol absorption directly - PTI methods to the rescue
Griša Močnik, unpublished invited conference lecture

Found in: ključnih besedah
Summary of found: ...aerosol absorption, black carbon, climate change...
Keywords: aerosol absorption, black carbon, climate change
Published: 19.07.2022; Views: 92; Downloads: 0
.pdf Fulltext (10,97 MB)

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