ACCESS Lab @ Westlake University (PI: Yuzhong Zhang)

Atmospheric Chemistry in Climate, Environmental & Sustainable Science

The air we breathe everyday consists of, in addition to the bulk of nitrogen and oxygen, a multitude of trace gases and particles. These trace compositions account for only a tiny fraction of air (from parts per million down to even parts per trillion), as compared to nitrogen and oxygen, but they play critical roles in Earth’s energy balance, have huge impacts on the health of human, animals, and plants, and are closely associated with critical environmental issues that we are facing today, for example, air pollution, acid rain, ozone hole, and climate change.

Our research focuses on better understanding these atmospheric trace species, their properties and distributions, their sources and sinks, and their interactions with human and nature. In particular, we are interested in methane emissions and its budget, atmospheric oxidation power, light absorbing brown carbon, and regional air pollution. We develop novel modeling and analysis tools to interpret big environmental data collected from multiple platforms (e.g., satellite, aircraft, surface networks), and gain insight into mechanisms that regulate key atmospheric species across spatial and temporal scales. Through our research, we aspire to bridges the knowledge gap in pressing environmental issues and inform scientific information to policy makers and the public.

Ongoing projects in our group include:

Greenhouse gas methane

Methane is a potent short-term greenhouse gas. We use satellite- & ground-based observations to identify and quantify methane emissions in different regions and across different spatial & temporal scales. We also try to understand the global and regional budget of atmospheric methane and its perturbations by human activities & natural variabilities.

Atmospheric oxidation capacity

Oxidation capacity of the global atmosphere is largely determined by the global mean concentration of the hydroxyl radical (OH). But there is no easy way to measure this key parameter in atmospheric chemistry directly. Our work in this topic includes (1) development of novel methods to infer global mean OH concentrations from observations of its proxies and (2) assessment of natural processes that govern the inter-annual variability of global OH. This information will help us better understand the global budget and the chemical feedback of atmospheric methane now and into the future.

Light absorbing organic aerosols

Organic aerosols that absorbs shortwave radiation is termed as brown carbon. Brown carbon is found to be emitted mainly from low-temperature imcomplete combustion, which often occurs during forest fires and biofuel use. We use atmospheric models to interpret the observed distribution of brown carbon and assess its impact on climate and chemistry.

Here is a video introduction of our group: 走进西湖大学工学院张羽中教授的大气环境研究实验室