Aerosol chemical speciation monitor

Description

Ambient particles are known to play a significant role in altering the chemistry and the radiative balance of the Earth’s atmosphere, reducing visibility, and adversely affecting human health. The chemistry of atmospheric aerosol has been the subject of much research. In order to address aerosol effects on health and the environment, instrumentation is needed that is capable of reporting the chemical and microphysical properties of atmospheric particles. We present results on the development and demonstration of a compact aerosol mass spectrometer system, the Aerosol Chemical Speciation Monitor (ACSM), which measures aerosol mass and chemical composition of non-refractory submicron aerosol particles in real time. The ACSM provides composition information for particulate ammonium, nitrate, sulfate, chloride, and organics. It is designed and built on the same technology as our larger research-grade Aerosol Mass Spectrometer (AMS), combining an aerodynamic particle-focusing lens with high vacuum thermal particle vaporization and mass spectrometric analysis. The system is smaller, uses lower-cost components, and thus operates with lower performance than the research-grade AMS. The ACSM is designed for longer-term routine monitoring of PM with sufficient sensitivity to provide chemically speciated mass loadings and aerosol mass spectra at data rates up to 15 minutes for typical urban aerosol loadings. Results are presented from recent field trials that compare the ACSM performance with collocated aerosol chemical instruments. Data quality and data analysis methods will be presented, and updates on the deployment of the DOE ARM ACSM systems will also be presented.