Title: Tracking atmospheric transformation and health risks of emerging organic pollutants through nontargeted analysis
Abstract:
Ambient air pollution, comprising numerous known and previously unidentified compounds originating from complex primary emissions and secondary formation processes, is a major risk factor for public health. Identifying harmful components is a prerequisite for effective pollution control; however, recognizing unknown and emerging species remains a significant challenge. In this seminar, I will present several case studies demonstrating how nontargeted analysis can be applied to identify emerging pollutants, track their atmospheric transformation, and evaluate their potential health risks. In the first study, we developed a nontargeted approach to characterize particulate electrophilic compounds in urban Beijing and identified compounds exhibiting significant diurnal variation. The relationships between night-to-day variation and molecular characteristics, particularly the significant negative correlation with oxygen-related features such as carbon oxidation state, indicated that multigenerational daytime oxidation processes predominantly drive diurnal differences. In the second study, nontargeted analysis was applied to polycyclic aromatic hydrocarbons (PAHs), oxygenated and nitrated aromatic compounds (OACs and NACs) to investigate their atmospheric transformation in urban environments. Gas-phase and heterogeneous photochemical reactions were identified as key factors influencing the diurnal variation of these compounds. These findings provide important insights into the dominant daytime removal processes of organic pollutants and highlight the critical role of atmospheric transformation in determining their environmental fate. In the third study, we present a pilot study integrating passive air sampling, in vitro bioassays, and targeted and nontargeted chemical analyses to characterize and prioritize atmospheric chemical mixtures in Sarnia, Ontario, a representative petrochemical industrial city in Canada. Multiple statistical approaches, including correlation, hierarchical clustering, and network analyses, were employed to systematically identify chemical species potentially associated with biological responses. Together, these studies demonstrate how nontargeted analysis can advance our understanding of the atmospheric transformation and health risks of emerging organic pollutants. They also provide a practical framework for prioritizing chemicals of concern and supporting environmental risk assessment and regulatory decision-making.Bio:
Dr. Zhen Cheng is a Postdoctoral Research Scientist in the Environmental Effects Research Division (EERD) at Environment and Climate Change Canada (ECCC). In January 2024, he earned his Ph.D. in Environmental Health from the College of Environmental Sciences and Engineering at Peking University under the supervision of Prof. Xinghua Qiu. Prior to that, he completed a Bachelor of Science in Chemistry at the College of Chemistry and Molecular Engineering at Peking University. His research interest is developing and applying nontargeted strategies to discover the emerging pollutants in the atmosphere and tracking their atmospheric transformation and potential health risks. Now he co-works with Dr. Amandeep Saini and Dr. Tom Harner in the Hazardous Air Pollutants (HAPs) Lab to identify the legacy and emerging pollutants from the chemical mixtures in the regional and global atmosphere and further explore the linkage between the organic pollutants and biological effects, contributing to a deeper understanding of urban air quality and its implications for public health.
Speaker(s)
- Zhen Cheng
Environment and Climate Change Canada
