Research Associate (2006-2008)
My research interests are to understand the patterns of inter-continental transport of air pollution and to study the related environmental policies for global air pollution control. Specifically, I'd like to 1) use regional and global atmospheric models to analyze the physical and chemical evolution of air pollutants, 2) evaluate the impacts of anthropogenic emissions on human health, ecosystems, agriculture and global change, 3) explore the policy motivations among industrialized and developing nations to address the air quality problem of local and inter-continental transport of air pollution, and (4) develop effective environmental policies (both local and international) on air pollution control. I work with Professor Denise Mauzerall and collaborate closely with Dr Larry Horowitz at Geophysical Fluid Dynamics Laboratory (GFDL).
My previous research focuses on determining the pathways and timescales of inter-continental transport of air pollution. In particular, I have used MOZART-2, a 3D global chemical tracer model (Model of Ozone And Related Tracers, version 2) driven with NCEP reanalysis meteorology to examine the trans-Pacific transport patterns for Asian and European emissions. Nine continental tracers (with first order decay rate) were used and their trans-Pacific transport potentials, including seasonal and inter-annual variability, were estimated. Transport pathways and regions with the highest transport ability were identified. Meteorological factors that control the inter-annual variability of trans-Pacific transport were investigated. We created an index, called Eastern Pacific Index (EPI), which can capture most of the inter-annual variations of the trans-Pacific transport. Moreover, I have evaluated the relationship between tracer lifetimes and tracer concentrations, and quantified the average transport time for inter-continental transport. We determined that the average transport time depends on the tracer lifetime used and can be approximately represented by an 'equivalent circulation' approach. In addition, the average time of inter-continental transport that we calculated was approximately 3-weeks, 1-2 weeks longer than has been observed in rapidly transported plumes.
My current research focuses on the source-receptor relationship of inter-continental transport of fine aerosols (including sulfate, black carbon, organic carbon and mineral dust), and evaluates the related human health impact. We conduct a 7-year simulation with the tagged aerosol species originated from 10 continental regions. Both anthropogenic and biomass burning emission inventories are selected for the year 2000. We evaluate the model results with the observations around the world, including IMPROVE (United States - rural), EMEP (Europe), EANET (East Asia), and the global data collected by the University of Miami (RSMAS). The health impact (i.e., premature mortality) caused by domestic and intercontinental sources of fine aerosols are quantified. To address the policy relevant questions related to inter-continental transport of air pollution, we defined an "influence potential", namely the emission normalized, population weighted air pollution concentrations. Based on the modeling results and influence potential ratio among different continents, we investigate the potential incentives among industrialized and developing regions to cooperatively mitigate sulfate emissions.
Liu, J., Mauzerall, D. L., Horowitz, L.W., “Evaluating the Global Health Impact of Inter-Continental Transport of Fine Aerosols”, Journal of Geophysical Research-Atmosphere (In preparation).
Liu, J., Mauzerall, D. L., “Evaluating the potential influence of inter-continental transport of sulfate aerosols on air quality”, Environmental Research Letters, in press, July 2007.
Liu, J., Mauzerall, D. L., Horowitz, L.W., “Source-Receptor Relationship of Trans-Pacific Transport of East Asian Sulfate”, Geophysical Research Letters (submitted).
Liu, J., “Evaluating Inter-Continental Transport of Air Pollution and Its Impacts on Global Health: Implications for Regional and Global Cooperation to Mitigate Long-Range Trans-Boundary Transport of Air Pollution”, Ph.D. Dissertation, 2006
Liu, J., and Mauzerall, D. L., “Estimating the Average Time for Inter-continental Transport of Air Pollutants,” Geophysical Research Letters, 32, L11814, doi:10.1029/ 2005GL022619, 2005.
Liu, J., Mauzerall, D. L., Horowitz, L.W., "Analysis of Seasonal and Inter-annual Variability in Transpacific Transport,” Journal of Geophysical Research-Atmosphere, 110, D04302, doi:10.1029/2004JD005207, 2005.
Liu, J., “Environmental Taxation Policy on Recovery of Ecosystems in Western China”, China Environment News, Dec 7, 2004 (in Chinese)
Mackie, D., J. Liu, Y.S. Loh, and V. Thomas, “No Evidence of Dioxin Cancer Threshold”, Environmental Health Perspectives, 111 (9), 1145-1147, 2003.
Liu J., Li J., “A comparison of Atmospheric Photo-Chemical Mechanisms（I）O3 and NOx”. Environmental Chemistry, Vol.20, No.4, 2001 (in Chinese)
Liu J., Li J., “A comparison of Atmospheric Photo-Chemical Mechanisms （II）HOx and Photo-Chemical Products”. Environmental Chemistry, Vol.20, No.4, 2001 (in Chinese)
Liu J., “A Comparison of Four Photochemical Reaction Mechanisms”, Master Thesis, Peking University, 2000 (in Chinese)
Liu J., Li J., Bai Y.. “The Parameterization of Hydrogen Ion Concentration in the Rainfall”. Research of Environmental Sciences, 13(1), 18-21, 2000 (in Chinese)
Liu J., Li J., Bai Y.. “The Numerical Solvers for Atmospheric Chemistry Models”. Research of Environmental Sciences, 13(1), 39-44, 2000 (in Chinese)
Liu J., “The Synthesis and Characterization of Electric Poly-Aniline”, Undergraduate Thesis, Peking University, 1997 (in Chinese)