CIMS

Aerosol Life Cycle: Chemical Ionization Mass Spectrometer - CIMS

10 July 2011 - 10 August 2011

Lead Scientist: Shanhu Lee

Observatory: OSC

New particle formation (NPF) is an important initial step in the chain reactions that lead to cloud formation but the NPF mechanisms are poorly understood. Sulfuric acid is the main aerosol nucleation precursor, but there are only a very limited number of studies that have simultaneous measurements of aerosol sizes and sulfuric acid. We provided measurements of sulfuric acid with high sensitivity of chemical ionization mass spectrometer (CIMS) for the aerosol size measurements (by Dr. Gannet Haller, DRI) to understand the role of sulfuric acid in NPF with different airmasses representative of clean marine air, biogenic environment, urban pollution, and possible biomass burning. An atmospheric-pressure, high-sensitivity chemical ionization mass spectrometer (CIMS) was used to detect the gas phase sulfuric acid concentrations down to the e5 cm-3 order. This is one of the very few instruments in the world that have the capability to measure such low concentrations of sulfuric acid with 1 Hz time resolution.