Suchergebnisse

Airborne black carbon particles are monitored in many networks to quantify its impact on air quality and climate. Given its importance, measurements of black carbon mass concentrations must be conducted with instruments operating in a quality checked and assured conditions to generate reliable and comparable data. According to WMO (World Meteorological Organization) and GAW (Global Atmosphere Watch), intercomparisons against a reference instrument are a crucial part of quality controls in measurement activities (WMO, 2016). The WMO-GAW World Calibration Centre for Aerosol Physics (WCCAP) carried out several instrumental comparison and calibration workshops of absorption photometers in the frame of ACTRIS (European Research Infrastructure for the observation of Aerosol, Clouds and Trace Gases) and the COST Action COLOSSAL (Chemical On-Line cOmpoSition and Source Apportionment of fine aerosoL) in January and June 2019. The experiments were conducted to intercompare filter-based particle light absorption photometers, specifically aethalometers AE33 (Magee Scientific), which are operated by research institutions, universities or governmental entities across Europe. The objective was to investigate the individual performance of 23 instruments and their comparability, using synthetic aerosols in a controlled environment and ambient air from the Leipzig urban background. The methodology and results of the intercomparison are presented in this work. The observed instrument-to-instrument variabilities showed differences that were evaluated, before maintenance activities (average deviation from total least square regression: 1.1 %, range: −6 % to 16 %, for soot measurements; average deviation: 0.3 %, range: −14 % to 19 %, for nigrosin measurements), and after they were carried out (average deviation: 0.4 %, range: −8 % to 14 %, for soot measurements; average deviation: 1.1 %, range: −15 % to 11 %, for nigrosin measurements). The deviations are in most of the cases explained by the filter material, the total particles load on the filter, the performance of the flow systems and previous flow check and calibrations carried out with non-calibrated devices. The results of this intensive intercomparison activity show that relatively small unit-to-unit uncertainties of AE33-based particle light absorbing measurements are possible with functioning instruments. It is crucial to follow the guidelines for maintenance activities and the use of the proper filter tape in the AE33 to assure high quality and comparable BC measurements among international observational networks.

This investigation presents the variability of near-surface in-situ aerosol particle light scattering measurements obtained over the past decade at 28 measuring atmospheric observatories which are part of the ACTRIS Research Infrastructure and most of them belong to the GAW network. This manuscript provides a comprehensive picture of the spatial and temporal variability of aerosol particles optical properties in Europe. ; This project has received funding from the European Union's Horizon 2020 research and 11 innovation programme under grant agreement No 654109, ACTRIS (project No. 262254), ACTRIS12 PPP (project No 739530).MAD station is co-financed by the PROACLIM ( CGL2014-52877-R) project. SMR station acknowledges BACCHUS (project No. 603445), CRAICC (project No. 26060) and Academy of Finland (project No. 3073314). UGR station is co-financed by the Spanish Ministry of Economy and Competitiveness through project CGL2016-81092-R. Measurements at Montseny and Montsec stations were supported by the MINECO (Spanish Ministry of Economy and Competitiveness) and FEDER funds under the PRISMA project (CGL2012-39623-C02/00), by the MAGRAMA (Spanish Ministry of Agriculture, Food and Environment) and by the Generalitat de Catalunya (AGAUR 2014 SGR33 and the DGQA). Measurements at Izaña were supported by AEROATLAN project (CGL2015-17 66229-P), co-funded by the Ministry of Economy and Competitiveness of Spain and the European Regional Development Fund. Station Košetice is supported by Ministry of Education, Youth and Sports of the Czech Republic within project for support of national research infrastructure ACTRIS – participation of the Czech Republic (ACTRIS-CZ – LM2015037). Measurements at Puy de Dôme were partly supported by CNRS-INSU, University Clermont- Auvergne, OPGC and the french CLAP program. PAL station acknowledges KONE Foundation, Academy of Finland (project No. 269095 and No. 296302). CHC station received support from Institut de Recherche pour le Développement (IRD) under both Jeune Equipe program attributed ...