10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Chemistry of Ice Nucleating Particles in Summertime Urban/Marine Conditions
MARIA ZAWADOWICZ, Michael Roesch, Martin Wolf, Daniel Cziczo, Massachusetts Institute of Technology
Abstract Number: 1067 Working Group: Unraveling the Many Facets of Ice Nucleating Particles and Their Interactions with Clouds
Abstract Formation of ice in the atmosphere depends critically on the availability of ice nucleating particles (INPs). Field and laboratory measurements indicate that a small fraction of tropospheric aerosol particles are efficient INPs and that their chemistry is distinct from that of bulk aerosol. Although the specific chemical qualities that govern ice nucleation efficiency remain uncertain, mineral dust, metallic anthropogenic particles and certain species of bioaerosol have been shown to be efficient INPs in field and laboratory studies. In this experiment, a single particle mass spectrometer (Particle Analysis by Laser Mass Spectrometry, PALMS) was coupled to a continuous flow diffusion chamber (Spectrometer for Ice Nuclei, SPIN) using a pumped counterflow virtual impactor (PCVI). The resulting instrument combination allows direct measurement of ambient INPs under a range of temperature and saturation conditions and simultaneous characterization of chemical composition of their residuals. The technique was validated in the laboratory and deployed in downtown Cambridge, MA to sample air masses of continental and marine origin, strongly influenced by Boston-area pollution. Temperature and saturation conditions consistent with deposition and immersion ice nucleation modes were used.