Bio-tracking sources of atmospheric pollution using a multi-isotope approach

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Air pollution is today a major societal issue for most countries. Environmental management of air quality is almost exclusively based on monitoring pollutant levels in a selection of sites and samples through time. However, there is now ample evidence that this does not allow to unambiguously establish the different pollution sources and their respective contributions. Recent research showed that these limitations can be overcome by using isotopes. Although the application of the isotope tracing approach is fairly recent, it has proven to be effective at precisely discriminating and identifying the different vectors of pollution, and quantifying their respective contributions.******The objective of this research program is to demonstrate that integrating isotope data in air quality monitoring networks is technologically feasible and leads to more effective planning of environmental management measures. This program will specifically address key atmospheric pollution issues (identification of sources of air pollution, semi-quantification of their respective contributions, characterisation of secondary processes); in particular, inorganic pollutants, including toxic metals of high environmental impact, such as osmium (Os), cadmium (Cd) or mercury (Hg), will be investigated. The overall research program will be organised into two complementary research axes. First, we will test the possibility of using bioindicators (mosses/lichens) as passive samplers for isotopically (S, Pb, Sr, Os isotopes) tracing sources/processes controlling their budget in the air. The second part of the program will be in continuation with this work, extending this study to other metal isotopes (Hg, Cr, Cd, Zn, Cu).******This research program will support research conducted by four graduate students at UQAM. The first part of the program on bioindicators will help train two PhD students. The second part of the program on metal isotopes will support two more PhDs. The candidates will have the opportunity to work within an active research group in Earth Sciences at the GEOTOP center. They will also benefit from my 17-year experience studying air pollution as well as from another study that I am currently supervising: S isotope characterisation of emissions from urban sources of air pollution and aerosols.******The originality of this program resides in the multi-isotope characterisation of bioindicators that are here used as air passive samplers. This will also constitute one of the very first studies coupling a mass-dependent and mass-independent isotope fractionations approach. The methodology proposed here will provide a better understanding of the sources of air pollution to be controlled and acted against, as well as of the atmospheric processes involved. The integration of isotope measurements to the study of air-contaminated areas will thus constitute a high degree of innovation with respect to current practices.**