| Popis: |
This study presents part of the results of the CALISHTO campaign (Cloud-AerosoL InteractionS in the Helmos Background TropOsphere) that took place in autumn 2021 at the free-troposphere high-altitude Helmos station (2314 m a.s.l.). A Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM, Aerodyne) was deployed among other instruments (AE31, PVM-100, SMPS, EC/OC analyzer) in the framework of the campaign. The chemical characterization of the non-refractory PM1 (NR-PM1), the influence from the Boundary Layer / Free Troposphere, the origin of the incoming masses and the influence of clouds were studied. The sources of PM1 including the non-refractory species of ACSM (organics and inorganics) combined with the equivalent black carbon were also investigated by applying the PMF model to the combined dataset. The results showed that there is a great variability of aerosol characteristics depending on the height of the PBL and the origin of the air masses. During September the station was exposed to PBL emissions, and thus displayed much higher mass concentrations of NR-PM1 than October and November. Concerning the sources of PM1, different types were identified with ammonium sulphate and oxygenated organics being predominant, as expected for aged aerosol with the degree of ageing investigated against air mass origin and microphysical parameters. |
