[KEYNOTE] Beyond mass: Mechanisms, metrics, and the hunt for determinants of PM health effects

"Keynote talk:

Particulate matter (PM) has long been associated with increased morbidity and mortality, estimated to contribute to over 17,000 premature deaths in Canada and millions worldwide. In Canada, as in other jurisdictions, standards set according to mass concentrations have prompted action to reduce PM levels to protect health. However, mass is far from the only determinant of health effects. Identifying determinants of PM health effects – whether these be ultrafine particles, metals, oxidative potential, etc. – and their sources, could help to identify the emissions of greatest concern. PM is a heterogeneous mixture that varies spatially and temporally, presenting a vast array of physical and chemical properties that may contribute to adverse health outcomes individually or through interactions, including with other pollutants. Identifying the relative importance of specific components (“what is in the air that hurts us?”) from these complex mixtures represents an immense challenge. Elucidating underlying mechanisms (“how does it hurt us?”) for the growing list of adverse health conditions associated with particulate air pollution is also critical to establish causal links and to better understand factors governing susceptibility.

This talk will provide a toxicological perspective on some of the advances made and challenges encountered through efforts to tackle these questions. It will explore how both physical and chemical characteristics contribute to toxicity. It will also describe how our characterisation of underlying mechanisms can provide insight into how effects on health are shaped not only by particle characteristics, but also by our own individual sensitivity. Finally, the accelerated development of new toxicity testing approaches and the need to assess their strengths and limitations – especially in relation to how well models predict health outcomes – will be described.

Speaker Bio:

Dr. Errol Thomson is a Research Scientist in the Environmental Health Science and Research Bureau of Health Canada, where he leads the Inhalation Toxicology Lab. He is also Adjunct Professor in the Department of Biochemistry, Microbiology, and Immunology at the University of Ottawa. His research group investigates the toxicity of inhaled pollutants, including characterising underlying mechanisms and relating biological effects to determinants of toxicity. His group is also actively establishing and evaluating the utility of new approach methods for toxicity testing of inhaled pollutants, in support of hazard identification and risk assessment initiatives."