Humidified Tandem Differential Mobility Analyzer (HTDMA). The HTDMA is used to measure the hygroscopic growth of aerosol particles of a specified diameter. The instrument consists of two Scanning Electrical Mobility Spectrometers (SEMS): an upstream (dried) SEMS and a humidified SEMS. The upstream SEMS creates a monodisperse flow of dry particles of a specific diameter, which is then split between a condensation particle counter (CPC) and the humidified SEMS. The humidified SEMS humidifies the dry, monodisperse particles to a given relative humidity and measures the resulting size distribution. The growth (or lack of growth) of aerosol particles as a function of relative humidity can show how aerosol particles uptake water and grow in the atmosphere. We can use this to measure hygroscopicity of particles and relate that to their composition.
Scanning Electrical Mobility Spectrometer (SEMS). The SEMS measures the number size distributions of aerosol particles using electrical mobility. The instrument is made up of a Differential Mobility Analyzer (DMA) to select particles of a given size and a Mixed Condensation Particle Counter (CPC) to count the monodisperse particles. Based on the electric field and sheath flow within the DMA, the aerosol particles will drift according to their electrical mobility which is a function of their size. By adjusting the voltage of the DMA, particles can be selected based on size and counted in order to give an overall number size distribution of the sample flow. The number size distribution of aerosol particles can give information about the size and number of particles and their fate in the atmosphere.
Aerodynamic Particle Sizer (APS).
Fourier transformer infrared (FTIR) with Attenuated Total Reflectance (ATR).
Ion Chromatography (IC).
Pendant Drop Tensiometer.
Aerosol Optical Trap with Raman Spectroscopy.