Multi-Analysis Aerosol Reactor System (MAARS)

A unique apparatus, Multi-Analysis Aerosol Reactor System (MAARS), was constructed to measure heterogeneous chemistry, phase transitions, hygroscopicity, cloud condensation nuclei activity, and infrared extinction of aerosols. MAARS is equipped with multiple tools to measure the properties of aerosols, including a differential mobility analyzer (DMA-1) for size selection; a scanning mobility particle sizer (SMPS), which consists of a second DMA (DMA-2) and a condensation particle counter (CPC), and an aerodynamic particle sizer (APS) for measuring aerosol size distributions in the range from 10 nanometers to 20 microns; a continuous-flow streamwise thermal-gradient cloud condensation nuclei (CCN) counter for determining CCN activity; an FTIR spectrometer to measure extinction spectra and a reaction/hydration chamber, where aerosol can be exposed to reactive gases to study heterogeneous chemistry or equilibrated at different RH for hygroscopic growth studies. The relative humidity is monitored throughout the system with multiple RH sensors.