(11h) Size-Dependent Chemical Compositions in Particulate Matters from Major Outdoor Sources in a Megacity and Corresponding Inhalation Exposure Assessment

A variety of existing studies have characterized the chemical compositions in particulate matters (PM) for various megacities. However, these studies rarely accounted for the size-dependence of chemical constituents in PM, hindering the application of the data for inhalation exposure assessment and thus epidemiological studies. In this work, a series of field measurements were conducted to characterize the major emission sources of Singapore, i.e. traffic and industry emissions (coal combustion is rare in Singapore and thus disregarded). The particle size distribution and corresponding size-dependent chemical compositions were identified. Existing respiratory deposition models were employed to analyze the deposition distributions of particles and chemical compositions in the human respiratory system, based on the data of particle size and chemical compositions. Finally, potential protection suggestions were proposed to mitigate the PM exposure for susceptible populations. The data in this work will be also representative to other megacities whose particulate air pollution is mainly derived from traffic and industry emissions.

Research Interests:

Dr. Siming Youâ??s research interests fall under the umbrella of the interactions between environment and energy systems. He is trying to explore the potential environmental problems underlying existing energy systems, and understand and solve environmental problems from an energy point of view. Graduated from Nanyang Technological University as the top PhD student in Thermal and Fluids Engineering in 2014, he accumulated significant interdisciplinary research experiences by studying human exposure to harmful particulate matters (PM), especially, pathogens, and thus infection transmission from a physicochemical point of view. He then pursued his postdoctoral research at the Department of Civil & Environmental Engineering, Massachusetts Institute of Technology, and gained a deeper understanding of the transport dynamics of harmful PM in environments and inhalation exposure-related health implications. He is now a research fellow at Professor Chi-Hwa Wangâ??s group at the National University of Singapore, where he is investigating the environmental impacts and challenges of sustainable energy systems and proposing solutions to the potential environmental problems facing sustainable energy systems.

Teaching Interests:

I would like to teach Fluid Mechanics for undergraduate students, and Aerosol Technology and Environmental Health for both undergraduate and graduate students.

Fluid Mechanics is one of the most actively developing fields of physics and one of the basic core courses of engineering. Significant parts of my PhD studies and postdoctoral study at MIT have devoted to understanding how harmful particles transport in environments under the effects of aerodynamic forces. Specifically, I have accumulated a significant amount of knowledge about turbulence, such as the characteristics of turbulent bursts and the methods of quantifying turbulence parameters. These past research experiences and knowledge did lay a solid foundation to enable me to participate in this course on Fluid Mechanics.

Aerosol is ubiquitous throughout the world and the related technology has been widely employed in various fields such as microelectronic industry, pharmaceutical industry, environmental sciences, etc. The course of Aerosol Technology would cover the fundamental properties and behaviors of aerosols, aerosol sampling methods, and the application of aerosol technology in various fields such as industry and environmental health sciences. This course would equip students with the ability to sample, analyze, and apply aerosols for their future requirements in either industry or academics.

Environmental Health would cover the knowledge about how natural and built environments may affect human health. It would present an overview of methods used to understand environmental health hazards, ranging from global issues such as climate change to regional issues such as air, water, and energy to local issues such as food safety, and occupational health, and to conduct risk assessment and risk management for environmental exposure-related health implications. This course would not only equip students with necessary knowledge and skills to address the potential concerns related to environmental health, but also encourage them to make positive changes in their behavior and attitude to protect the environment.