We present results from source apportionment analysis on the carbonaceous aerosol particles, including organic aerosol (OA) and equivalent black carbon (eBC), allowing us to distinguish local emissions from long-range transport for OA and eBC sources. By merging online chemical measurements and considering particle number size distribution, the different air masses reaching the sampling place were described and discussed, based on their respective chemical composition and size distribution.

We analyzed the composition of cloud droplet residuals and of aerosol particles sampled on a mountaintop site. The data show that about 85 % of the submicron aerosol mass partitions into the cloud phase, and that the uptake of soluble compounds (nitric acid, ammonia, and organic gases) from the gas phase into the cloud droplets is very effective. This will lead to a redistribution of these compounds among the aerosol particles and thereby to a more uniform aerosol after cloud evaporation.

This paper reports on single-particle measurements of ambient aerosol particles and cloud residues sampled from orographic clouds on a mountain site in central Germany. The results show that soot particles can get efficiently activated in cloud droplets when they are mixed with or coated by sulfate and nitrate. Cloud processing leads to addition of nitrate and sulfate to the particles, thereby increasing the hygroscopicity of these particles when they remain in the air after cloud evaporation.