LLE: Assessing Exposures and Health Effects of Particle Radioactivity: An Emerging Research Field (Petros Koutrakis, Harvard University)

October 18, 2023 @ 11:00 am – 12:00 pm
Sandford Fleming Building, Room 1105
10 King's College Rd
ON M5S 3G4

Petros Koutrakis, Harvard University

Host: Prof. Jeffrey Brook

The recent Global Burden of Disease (GBD) study estimated that long-term exposure to fine particulates (PM2.5) caused 9 million deaths worldwide in 2019, making it the fourth-ranked global risk factor for that year. The PM properties responsible for its toxicity are still not fully understood. Recently, we found that radon (Rn) exposure is associated with mortality in the Northeastern U.S., and we have reported associations between PM gross β-activity and blood pressure, oxidative stress, and lung and cardiac function. A large fraction of the total exposure to naturally occurring ionizing radiation is through inhalation of ambient particles carrying attached radionuclides. The primary source of this PM radioactivity (PR) is Radon (Rn) gas through its decay products. Rn emanates from the soil and enters the atmosphere, including indoor air, where it decays. The resulting radionuclides attach to inhalable PM, which deposit in the lungs and continue to release ionizing radiation (α-, β- and γ-radiation) causing pulmonary inflammation and oxidative stress. To date, most previous environmental radiation studies have focused on the cancer effects of Rn progeny, therefore, there are significant knowledge gaps regarding the non-cancer effects of radon and PR. Our recent research has demonstrated that these non-cancer effects are, in fact, very important. Specifically, we have generated new information showing that exposures to Rn as well as PM gross α-, β- and γ-activities are associated with numerous adverse health outcomes, including blood pressure, oxidative stress, cardiac, lung and liver function, gestational diabetes and hypertension, and total and cardiopulmonary mortality.

These observations provide strong scientific evidence for our hypothesis that inhaled Rn progeny and other radionuclides, measured as PR, can have direct health effects through stimulation of inflammatory and oxidative processes. Therefore, assessing exposures and effects of PR may be of paramount importance to understanding of particle toxicity. During my presentations I will summarize many PR studies regarding measurement methods, sources, relationships between indoor and outdoor levels and, toxicity assays. Also, I will present results from cohort studies examining a large spectrum of health outcomes and population mortality studies. Finally, I will discuss research needs to advance this emerging research area.


Petros Koutrakis has over 35 years of experience in environmental health sciences. His interests include human exposure assessment, ambient and indoor air pollution, environmental analytical chemistry, remote sensing, and environmental radioactivity. His research career has focused on studying exposure methods, developing sampling techniques for gaseous and particulate air pollutants, and studying the effects of air pollution on human health. His research group has conducted a large number of ambient and indoor air quality studies in the U.S. and abroad. These studies made it possible to identify and quantify the sources contributing to ambient, micro-environmental and indoor exposures. Finally, these investigations significantly advanced scientific knowledge of associations between exposures and health outcomes and made important contributions to assessments of the impacts of air pollution on human health in different populations.


View the complete 2023-24 LLE schedule

Questions? Please contact Michael Martino, External Relations Liaison (michael.martino@utoronto.ca)