My research interests are broad and overlap many fields: medical geography, geology and atmospheric sciences. This reflects in part the way my research has evolved since graduate school, and in part, my personal interests.  I have ongoing projects examining paleoceanographic events in the North Atlantic, the link between pollen, allergies, and other health problems, and the sources and impacts of air pollution on people.

Opportunities exist for students to get involved in any of these research projects, either as research assistants, honours student or graduate student. Please feel free to contact me.


  • Pollen and Allergies
  • Health Impacts of Air Pollution
  • Paleoceanography and paleoclimatology
  • Younger Dryas
  • Atmospheric Pollen Transport
  • Pollen Dating

Research Projects

  • Pollen and Seasonal Allergies

    Examining the link between allergies and medical consultations

    Pollen and Seasonal Allergies 4

    Proteins love your lungs!!!

    Well, kind of…proteins released by airborne pollen grains will trigger allergies in sensitive individuals. This is what we call rhinitis or seasonal allergies. Seasonal rhinitis is a major health problem in industrialized societies. Its incidence in North America is estimated between 10-30%. And pollen allergies are on the rise!

    Most seasonal allergy symptoms are only bothersome (runny nose, stuffy nose, sneezing, and watering eyes). But allergies to tree and grass pollen exacerbate asthma symptoms, and even lead to hospitalization. In Europe, a survey showed that 74-81% of asthma patients also reported rhinitis.

    Ongoing research projects

    Title: The relationship between airborne pollen concentrations and emergency visits in Sherbrooke, between 2007 and 2009.

    Title: Increasing trends in ragweed pollen in Sherbrooke 2006-2016.

    Funding from: Bishop’s University Senate Research Committee Research Grant 

    Co-investigator: Dr. Lourdes Zubieta

    For this project, we are using data from the Lennoxville Pollen Monitoring project to see if higher airborne pollen concentrations cause an increase in the number of emergency visits due to respiratory problems.

    Research opportunities exist for students with an interest about pollen and allergies.

  • Trends in Ragweed Pollen

    Is climate change having an impact?

    Trends in Ragweed 2

    Trends in Ragweed Pollen

    Herb Evolution

    Image from:

    The pollen of Ambrosia artemisifolia, more commonly called ragweed, is responsible for allergies in the late summer. Medical consultations for allergic rhinitis are significantly linked with Ambrosia pollen levels, and often remain higher than normal up to 5 days after exposure to high pollen levels.

    In the past, Sherbrooke was known as a place where late summer allergies were not as bad. Is it still the case? Thanks to data gathered by the

    Lennoxville Pollen Monitoring Project, we have daily data taken on site that will allow us to answer this question.

    Research question (and potential projects for graduate students):

    • How did ragweed pollen concentrations increase over the last decade in Lennoxville?
    • How much ragweed is transported from outside of Lennoxville?
    • Is the length of the ragweed pollen season changing or not?
    • How can we use climatic conditions from the previous year to anticipate the length and severity of the ragweed pollen season?
  • Health Impacts of Air Pollution in small towns

    Photo of Mount Orford and Montérégie region taken from Mont Chauve. In the distance, the Monteregian Hills are slightly visible when air quality is poor, but clearly visible when weather is fair and air quality is good (bottom picture).

    Air Pollution 4

    Health impacts of air pollution

    Air pollutants have been shown to aggravate asthmatic conditions in all age groups and have been linked with cardiac and respiratory diseases. Large scale studies have found an association between hospital admissions and mortality and pollutants such as particulates (dust) and ozone, both measured in Sherbrooke. Impact on health can occur even from short-term exposure to pollutants and at low pollution levels

    Ongoing project

    Title: The relationship between air pollution and emergency visits in Sherbrooke, in 2007 and 2008

    Funded by the Health and Well Being Research Cluster, Bishop`s University.

    Co-investigator: Dr. Lourdes Zubieta, Bishop`s University

    Research opportunities exist for students with an interest about pollen and allergies.

  • Source of Air Pollution in Southern Quebec


    View taken from Mt St-Hillaire on a polluted summer day

    Poor air quality episode 24-26 May 2007 due to fine particulate matter (PM2,5).

    The back trajectories modelled using HYSPLIT show the source of the air pollution is in the American Mid-West.
    From: Amy Gibbons, Undergraduate honours thesis in Environmental Studies and Geography, 2015-2016

    Thesis title: Investigating the occurrence of poor air quality and its relation to main sources of air pollution and weather systems

  • Paleoceanography and paleoclimatology

    of the Eastern Canadian Margin


       I am engaged in projects examining the impact that large meltwater drainage events (glacial floods) had on the ocean and on climate during the last deglaciation.

    Understanding the impact of adding large amounts of freshwater to the North Atlantic Ocean is important in view of the accelerating melting of ice sheets around the world.

    Abrupt Climatic Events of the Last Deglaciation

    Through analysis of numerous high resolution marine sediment cores, I was able to show that three cold climatic events (Sandercombe 2012; et al. 2010) do coincide with large meltwater drainage events that affected sea surface conditions (Levac et al. 2011; Levac et al. 2015) and slowed the deep oceanic circulation responsible for the latitudinal distribution of heat.

    The 8.2 ka cooling events coincided with the catastrophic drainage of glacial Lake Agassiz out of Hudson Strait (Levac et al. 2011; Lewis et al. 2012), while the Preboreal Oscillation (10900-11180 cal BP) and the Younger Dryas (12,900 to 11,700 cal BP) both coincided with meltwater drainage via the St. Lawrence River system (Anderson et al. 2007; Levac et al. 2015), but the Labrador Current is possibly playing a role….so, there is still lots of work to do!!

    Contact me if you are interested. Ongoing projects on the 8.2 ka event, the Preoreal Oscillation and the Younger Dryas.

  • Atmospheric Pollen Transport

    How far? How can we use this as a tracer?

    Atmospheric Pollen Transport

    Because tree pollen can travel over long distances, it can be used as a tracer for atmospheric circulation. Pollen samples from the high Arctic and from Sable Islands (offshore Nova Scotia), two locations where there are no trees, are analyzed  and atmospheric models are used to determine the source of the pollen.

    This knowledge will be applied to study past changes in atmospheric circulation. And I will then put the variability of sea surface conditions during the Holocene in relation with changes in atmospheric circulation.

    Loss of sea ice in the Arctic will no doubt affect the way air masses circulate. And winds also exert a certain control on oceanic currents. And to close the loop, oceanic currents affect the climate.  With a better understanding of the links between ocean and atmosphere, we will be better prepared to anticipate the impacts of climate change!

    This is an ongoing project and students interested in graduate studies are welcome to contact me.


    Pollen sampler on the roof of Eureka

    Pollen Sampler on the roof of Eureka

  • Pollen Dating

    Developing an alternative 14C methods

    Pollen Dating 2

    • I am also leading a research project on the atmospheric transport of pollen and working at developing an alternate 14C dating method using pollen grains instead of carbonate shells.