Date: Friday, Aug 29th, 2014
Location: UBC Chemistry D215
Speaker: Dr. Yaacov Mamane, Technion, Israel (Environmental Engineering)
Title: Transport of Anthropogenic Elements on Saharan Dust Along the East Mediterranean
This study focuses on the possibility that dust storms minerals are "collecting" anthropogenic particles along their transport pathway to the East Mediterranean. The study involves:
(1) Intensive sampling campaigns to characterize PM10 particles during seasons with high occurrence of dust storms. 24 hr samples of fine and coarse particles were collected up to four weeks with dichotomous samplers in various sites along the coast. Teflon filters were analyzed for gravimetric and elemental analysis (using XRF). Quartz, and Nuclepore filters were also used.
(2) Study of individual particles using scanning electron microscopy.
Analyses of samples collected during dust storm showed high concentrations the presence of alumino-silicate elements in during the dust storm events. Ca concentrations (as calcite and dolomite) were often higher than Si. Those findings were true for both the coarse and fine particle fractions. Sea salt elements were associated with dust storms events, not necessarily on the same day, but a day later, the result of stormy meteorological conditions associated with Saharan dust transported to the East Mediterranean.
Heavy metals of anthropogenic origin were associated with the minerals. These include V and Ni, particles emitted from combustion of crude oil in Europe and in East Mediterranean, Pb, Zn, Se and As, oil from coal combustion sources. Coarse particle fractions could be explained by two factors (using principal component analysis): mineral elements associated with anthropogenic heavy metals, and sea salt. In the fine particle fraction this association has not been observed. Dust storms may be efficient in transporting anthropogenic constituents with them. The "coating" of minerals with heavy metal particles may have a significant impact on the radiative properties of minerals, and health effect.
Research led by Phil Austin (CREATE-AAP mentor) and his student Vlad Popa (CREATE-AAP student) was awarded 2014 Compute Canada Resource Allocation of 112 core years to conduct research on Westgrid consortium supercomputers.
In recognition of the quality of the science outlined in the proposal, the research was featured in the February edition of the Compute Canada Westgrid newsletter.
Date: Friday, May 9th, 2014
Location: UBC Chemistry D317
Speaker: Dr. Thomas Koop, Bielefeld University, Germany (Atmospheric and Physical Chemistry)
Title: Competition between water uptake and ice nucleation in glassy aerosol particles
Abstract: The phase state of condensed matter is of fundamental importance in various environmental systems, for example for heterogeneous chemical reactions and cloud formation processes in atmospheric aerosols. In this presentation both thermodynamic as well as kinetic aspects of different types of liquid-to-solid phase transitions will be reviewed, including ice crystal formation via homogeneous or heterogeneous nucleation processes. Moreover, the formation and properties of amorphous semi-solid and glassy states in organic aerosol particles and their dependence upon water content will be discussed. Such glass formation may delay or inhibit homogeneous ice nucleation owing to reduced diffusivities within the glassy state, but may also trigger heterogeneous ice nucleation at the surface of glassy particles, revealing a Janus-like behavior of glass-forming aerosol particles.