Prof. Allan Bertram

◆ Tel: 604-822-2113
◆ e-mail: bertram@chem.ubc.ca

Allan Bertram received his BSc from the University of Prince Edward Island and his Ph.D. from the University of Waterloo, where he studied the freezing behaviour of polar stratospheric clouds. Following an NSERC Postdoctoral Fellowship at the Massachusetts Institute of Technology, he joined the Department of Chemistry at the University of British Columbia (UBC) in 2001. He was a Tier II Canada Research Chair in Environmental and Atmospheric Chemistry from 2001-2011, and in 2012 he became a full professor at UBC. Currently, he is the director of an interdisciplinary atmospheric aerosol program funded through the NSERC CREATE program (2010-present) and serves as co-editor of Atmospheric Chemistry and Physics (2013 – present). The research in his group focuses on the chemistry and physics of atmospheric particles and the role these particles play in urban air pollution, climate change, and atmospheric chemistry. Current research projects focus on several topics, including liquid-liquid phase transitions, viscosity, and diffusion in atmospheric particles, heterogeneous chemistry, and laboratory and field measurements of ice nucleation.

Research and Teaching Interests

We focus on chemical and physical processes important in the atmosphere. Of special interest are atmospheric aerosol particles and their role in urban air pollution, climate change, and atmospheric chemistry. Ultimately our goal is to understand better the role of human activity on the Earth'­s atmosphere.

Atmospheric aerosol particles, which range from 10 to 10,000 nanometers, can affect Earth's climate by scattering or absorbing solar radiation and modifying the nucleation and reflectivity of clouds. For example, a recent analysis suggests that a large portion of Arctic warming may be attributed to atmospheric soot, a type of atmospheric aerosol. Poorly understood from a scientific standpoint, atmospheric aerosols constitute one of the largest uncertainties in predicting future climate change. Aerosol particles also negatively affect air quality and are largely responsible for visibility reduction in urban environments. Elevated levels of aerosol particles are also strongly correlated with increased cardio-pulmonary morbidity, according to epidemiological studies.

Heterogeneous atmospheric chemistry

Over the past two decades, laboratory, fieldwork, and modeling studies have conclusively shown that interactions between gas-phase species and atmospheric aerosol particles (termed heterogeneous atmospheric chemistry) can significantly influence the atmosphere's chemistry. One of our research goals is to identify key heterogeneous reactions that are important in the atmosphere. Atmospheric heterogeneous reactions are simulated and probed in the laboratory using aerosol reaction chambers, flow tube reactors, and state-of-the-art analytical techniques. We determine the fundamental kinetics and mechanisms of these reactions for incorporation into atmospheric models from the laboratory data.

Aerosol mass spectrometry (instrument development)

Aerosol mass spectrometry has emerged as an extremely powerful technique for investigating organic and inorganic particles in both the field and the laboratory. Although most aerosol mass spectrometers employ either a linear quadrupole or TOF-MS, ion trap mass spectrometers have been successfully used for single-particle analysis. Thus, another area of research in our group involves developing new types of aerosol mass spectrometers that incorporate ion trap mass spectrometry. This project is a collaboration with Michael Blades and John Hepburn in the department of chemistry at UBC.

Aerosol mass spectrometry (field studies)

To assess the impact of Asian particulate pollution on Western Canada and general trends in background aerosol, a state-of-the-art single-particle mass spectrometer designed and built at UBC is being deployed at Environment Canada'­s Whistler High Elevation site, located at the peak of Whistler Mountain, BC. This site offers the rare opportunity of nearly year-round measurements of tropospheric air unaffected by local background. This project is a collaboration with researchers at UBC (Allan Bertram and Ian McKendry), Environment Canada (Anne Marie MacDonald and Richard Leaitch), and Pacific Northwest National Laboratory (Daniel Cziczo).

Kinetics and mechanisms of ice nucleation in the atmosphere (laboratory studies)

Ice clouds in the troposphere play a key role in the Earth's climate system by strongly influencing the Earth­s radiative properties. These clouds form when ice nucleates on or in aerosol particles in the troposphere. Another area of research in our group focuses on understanding the mechanisms and determining the kinetics of these processes. Results from this project should provide building blocks for accurately representing ice clouds in climate models.

Ice nucleation (computer simulations)

The ice nucleation studies in our laboratory have also led to a collaboration with Gren Patey (UBC) involving computer simulations to better understand and predict ice nucleation on a molecular level. Currently, we are investigating ice nucleation on mineral dust surfaces containing defects such as steps, edges, and cracks using these simulations.

Hygroscopic properties and phase transitions of atmospheric aerosols

Atmospheric aerosol particles can undergo several types of phase transitions. Two types of atmospherically relevant phase transitions are deliquescence and efflorescence. We are currently studying these phase transitions for a range of atmospheric conditions to incorporate into atmospheric models. A wide range of instruments is being used for these studies, including optical microscopy, FTIR microscopy, and an electrodynamic balance.

Viscosity of atmospheric particles

The viscosity of aerosol particles is a fundamental property that is currently poorly quantified. However, information on the viscosity of these particles is required for accurate predictions of particle growth, mass, and removal, all of which are closely connected to air quality and climate predictions. To quantify the viscosities of aerosol particles, we developed two new techniques, namely a bead mobility technique and a poke-flow technique combined with fluid simulations. Using these techniques, we determine the viscosities of aerosol particles as a function of relative humidity. Moreover, we apply this new data to predictions of air quality, visibility, and climate.

Ice nuclei (field studies)

Ice nucleation studies extend to field sites in Canada and abroad. Several projects involve collaborative work as part of the Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE). For example, in France, the BIODETECT 2014 summer campaign focused on aerosols of biological origin (bacteria, fungi, pollen). Aerosol particles from these field sites are collected and characterized for their ice nucleation ability, INP concentrations, and composition.

For more information on specific projects, please see the Bertram Group Homepage.

Bertram Group Homepage

Also, if you are interested in graduate studies at UBC, you may want to consider applying to the new NSERC-CREATE-Atmospheric Aerosol Program. This program has several unique opportunities, including fellowships, travel support, and internships.

NSERC-CREATE-Atmospheric Aerosol Program