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To evaluate the impact of atmospheric trace gases and aerosols on global climate and regional air quality, it is important to understand their sources, sinks, and chemical/physical processes. My research aims at applying chemical and isotopic analysis to study such questions. My cuurent research interests in the Stable Isotope Laboratory of INSTAAR include:

• Using stable isotopes to better constrain processes in the contemporary carbon cycle.
• Understanding the isotopic effect during important atmospheric chemistry processes.
• Exploring the interactions between the atmosphere, the biosphere, the hydrosphere, and humans. 

Here are some of my past research topics:

Investigating the origins and chemical processes of trace gases and aerosols

Secondary sulfate and nitrate aerosols are formed via several atmospheric oxidation processes of harmful pollutants (SO₂ and NO_x), thus understanding their origins and chemical processes is important. Stable isotopic compositions of sulfate and nitrate aerosols imprinted information about their origins and oxidation pathways, as molecules originated from different sources will show different isotopic compositions, and each oxidation pathway will alter the isotopes (called isotopic fractionation) differently. Our work examined isotopic compositions of sulfate and nitrate aerosols across a spectrum of environments, ranging from intense haze events in megacities to arid desert regions to pristine remote marine boundary layer. The results provided us with a new, independent diagnosis to evaluate our current understanding of the emission inventory of SO₂ and NO_x, and their atmospheric chemistry processes.

Experimentally quantifying isotopic effects during atmospheric chemistry processes

Utilizing stable isotopes as a tool to investigate the sources and chemistry of trace species in the atmosphere requires complete comprehension of how isotopic fractionations occur during crucial chemical and physical processes. Extensive studies, including laboratory investigations and theoretical calculations, have been focusing on quantifying such effects, but significant uncertainties remain. We conduct laboratory experiments to quantify isotopic fractionation factors during important atmospheric chemistry processes. Utilizing state-of-the-art atmospheric simulation chambers, atmospheric chemistry box models, and isotopic analysis, our work contributes to the fundamental understanding of the isotopic fractionations in the atmosphere, better enabling stable isotopes as a tool in atmospheric chemistry studies.

Developing novel analytical methods to better observe the atmosphere

Development in analytical methods will enhance our capability to observe the chemical and isotopic compositions of the atmosphere. I worked with the Global Monitoring Laboratory at the National Oceanic and Atmospheric Administration and developed a novel analytical method that utilizes a low-cost air sampling platform. This platform called the AirCore, allows us to sample the atmosphere from ground to mid-stratosphere (~25-28 km above ground). Our novel analytical method could then be used to analyze a suite of trace gases, including greenhouse gases and ozone depletion substances from AirCore samples. The principle of the new method, in the future, can be applied to various analytical instruments, and extract even more information from AirCore samples, including stable isotopic compositions of molecules of our interest.