Applied Physics Seminar: "Using Traveling Mass Spectrometers to Study the Changing Arctic"

Unprecedented, rapid sea ice loss is increasing open water, ship traffic, and development in the Arctic region. Processes at the surface (sea ice-snowpack-tundra-seawater) govern the chemical composition and energy budget of the Arctic atmosphere. Atmospheric aerosols, nanoparticles suspended in air, interact with radiation, forming cloud droplets and ice crystals, and depositing on surfaces, with significant climate effects. Arctic aerosol emissions are expected to rise with increasing oil and gas activities and the production of sea spray aerosol. In addition, photochemical reactions within the surface of snow grains produce trace gases that partition to the air above, reacting with the greenhouse gases ozone and methane, as well as the pollutant elemental mercury. Given the complexity and evolving nature of atmospheric aerosols and trace gases, as well as the challenges associated with Arctic measurements, significant uncertainties remain in our understanding of Arctic atmospheric composition and radiative impacts. The Pratt Lab specializes in transportable mass spectrometers to measure individual nanoparticles and trace gases in the field, having conducted several field campaigns in the Alaskan Arctic. In particular, we use a home-built single-particle mass spectrometer that couples single-particle tracking by light scattering with laser desorption-ionization and dual-polarity time-of-flight mass spectrometry to measure individual nanoparticles in real-time in the Arctic. I will discuss the operating principles of and results from our single-particle mass spectrometer, as well as our chemical ionization mass spectometer for real-time measurements of atmospheric trace gases.