那么,胺类又将对气候产生何种影响?在这点上研究才刚刚起步。其中一些胺类与酸的结合比氨气更强;某些结合甚至强到生成新的大气颗粒, 或者使得微小的颗粒得以长大。一旦颗粒长大,它们就可以形成雨滴,改变降雨,云层感光度和生存时间,也就可能向太空中反射更多的能量。Dr. Anthony Wexler目前正在和博士后Xinlei Ge和来自英国东英吉利大学的Simon Clegg教授一起,致力于更好地了解大气胺类的化学性质,以及它们是如何对大气颗粒产生影响,进而影响气候系统的。该项工作是由EPRI, NOAA和能源部资助。
A Close Chemical Cousin of Ammonia Plays Many Roles in Climate Change
The atmosphere is full of acids – sulfuric acid which is formed from sulfur dioxide emitted during combustion of sulfur-containing fuels, nitric acid which is formed from nitrogen oxides also formed during fuel combustion, and organic acids formed by atmospheric photo-oxidation of numerous organic compounds emitted naturally and by human activities.
But what about the alkaline compounds that can neutralize this acidity in the atmosphere? Ammonia is emitted by soils and animals, including cows, and is the primary neutralizer of atmospheric acidity.
In the California’s San Joaquin Valley, ammonia emitted from agricultural processes neutralizes all the local atmosphere acidity. But there is another class of compounds, also emitted by soils and animal operations that can neutralize acidity – the so called amines.
The concentration of amines in the atmosphere may increase in the future: Proposed carbon sequestration operations will use amines to remove carbon dioxide, the most important greenhouse gas, from power plant exhaust before it reaches the atmosphere. The intent is to recycle the amines during this process but some may escape increasing their atmospheric concentration.
So how do amines affect climate? We are just starting to understand their role. Some of them bind more strongly to the acids than ammonia; some bind so strongly that they may form new particles in the atmosphere or cause tiny particles to grow. Once the particles grow, they can form rain droplets, changing rainfall patterns and cloud brightness and persistence, possibly reflecting more energy back into space. Dr. Anthony Wexler is working with his post-doctoral fellow, Xinlei Ge and Professor Simon Clegg, a colleague at the University of East Anglia, UK, to better understand the chemical properties of amines and how they may affect particles in the atmosphere that influence climate. Their work is supported by the Electric Power Research Institute, National Oceanic and Atmospheric Administration and Department of Energy.