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Jennifer G. Murphy

Assistant Professor, Department of Chemistry, University of Toronto
Graduate Faculty Member, Centre for Environment
Canada Research Chair in Atmospheric and Environmental Chemistry (Tier II)

Murphy The focus of my research is the atmospheric chemistry of reactive nitrogen species.

While most of the nitrogen on the planet is present in the atmosphere as N2 gas, with a strong triple bond that makes it unavailable for use by the majority of organisms, natural and anthropogenic processes can convert this nitrogen to other forms (e.g. NH3, NO, N2O). Once converted into fixed form, a single nitrogen atom can play a role in multiple environmental cycles: participating in photochemical ozone production, being incorporated into particulate matter, contributing to radiative forcing, depositing into an ecosystem, leaching into groundwater, and contributing to eutrophication in coastal waters. Human activities such as industrial fertilizer production, crop cultivation, and fossil fuel combustion have greatly accelerated the rate of nitrogen fixation and now dominate the biogeochemical nitrogen cycle. Increasing the rate of nitrogen fixation has critical consequences for the chemistry, physics, and biology of the atmosphere and both terrestrial and aquatic ecosystems.

My research is targeted at questions that fall into the following three broad categories related to sources, transformations and sinks:

  • In what quantity and form are reactive nitrogen species emitted to the atmosphere from natural and anthropogenic (urban, industrial, and agricultural) sources?
  • How does the chemical composition of the atmosphere respond to inputs of reactive nitrogen and over what spatial and temporal scales does the impact exist?
  • How is the reactive nitrogen removed to the surface, does this represent an ultimate sink and what are the implications for the environment that receives the deposition?

To address these questions, my research group develops sophisticated analytical techniques (e.g. using chromatography and spectroscopy) and deploys instruments to the field to measure reactive nitrogen constituents such as NH3, NO, NO2, HNO3, HONO and particulate NH4+, NO2- and NO3-. We collaborate with scientists from the University of Toronto, other universities, the Ministry of the Environment and Environment Canada, to study issues related to air quality, acid deposition and climate change.

To learn more about this research, please visit my website: