The IMK-AAF has several decades of experience in aerosol physics, aerosol chemistry, and aerosol characterisation methods. A comprehensive suite of aerosol instruments is available, including
- Aerosol generators
- Number and size distribution instruments
- Particle surface aera (BET, diffusition charger)
- Environmental scanning electron microscopy (ESEM)
- Optical particle counters
- Filter and impactor sampling techniques
- Analysis of filter samples (MS, INP)
- Aerosol mass spectrometry
- Aerosol LIDAR
- Cloud condensation nuclei (CCN) counter
- Contiuous flow diffusion chamber ice nuclei counter
Nanometer sized particles are generated with eletrospray techniques. Aqueous inorganic and organic solution particles with diameteres between about 10 and 1000 nm are made by dispersion of respective bulk solutions with atomizers, nozzles, or ultrasonic nebulizers. Aqueous particles can also be tranferred into a solid cristalline state when passed through an aerosol diffusion adsorption dryer. Soot particles are generated with a spark generator (GfG1000) and the combustion aerosol standard burner (CAST). The CAST burner can be operated a variable fuel to air ratio to generate combustion particles with variable organic carbon content. Dry powders like desert dust samples are dispersed with a roating brush generator (RBG-1000), a rotating disk small scale powder disperser, or a homemade fluidized bed setup.
Number and size distribution
For measurements of the total aerosol number concentration we operate a suite of condensation particle counters (CPC). Aerosol number size distributions are measured with scanning mobility particle sizers (SMPS), optical particle counters (OPC), and aerodynamic particle sizers (APS) in the diameter range from about 5 nm to 1000 µm.
Aerosol mass spectrometry
Real-time, quantitative size resolved aerosol mass measurement for non-refractory fine particulate matter (40 nm to ~2.5 µm) is done by aerosol mass spectrometry (W-TOF-AMS, Aerodyne) for major compounds like nitrate, sulphate, and organics.
Chemical signature and size of single particles can be determined with a Laser Ablation of Aerosol Particles Time Of Flight Mass Spectrometer (LAAPTOF, AeroMegt GmbH). The instrument is capable of analyzing aerosol particles in the range of ~200 nm to ~2500 nm. It provides mass spectra of positive and negative ions from laser ablation at 193 nm as well as the size of the particles inferred from their time of flight.
Sensitive and selective, real-time identification and quantification of gas-phase compounds in sampled air is done with a chemical ionization high-resolution time-of-flight mass spectrometer (ToF-CIMS, Aerodyne Research). It can use multitude of reagent ions, including: Acetate, Iodide, Nitrate, and H3O(H2O)n. With the FIGAERO inlet it is capable of semi-continuous detection of both particle-phase and gas-phase compounds.
Volatile particle components and organic trace gases are measured with sensitivities in the lower ppt range using a proton transfer reaction mass spectrometer (PTR-TOF 4000 X2, Ionicon Analytik GmbH) with a CHemical Analysis of aeRosol ON-line (CHARON) particle inlet and a fast GC module to separate isomers.
Spatial distributions of aerosol particles are measured with a 3 D scanning depolarization Raman LIDAR (Raymetrics, LR111-ESS-D200) with 30 mJ at 355 nm.