Low carbon city: win-win strategy for global climate change and regional air pollution
低碳城市:全球气候变化和区域空气污染双赢战略
Ding Yihui(丁一汇)
National Climate Center(国家气候中心)
China Meteorological Administration(中国气象局)
Atmospheric aerosols and their roles in air pollution and climate change (大气气溶胶及其在空气污染和气候变化中的作用)
What is the atmospheric aerosols
Atmospheric aerosols are a complex chemical mixture of solid and liquid mixture of particles suspended in air. Their sizes range from the smallest superfine mode, with diameters of a few nanometers, to large coase mode particles, with diameters of a few micrometers or more. Between the superfine and coase mode particles are the fine mode particles, with diameters ranging from 0.1μm to a few micrometers. So, the typical size of atmospheric aerosols ranges between 0.001 and 10 μm that reside in the atmosphere for several days and weeks.
Source regions and long-distance transport of atmospheric aerosols, leading to extensive areas of air pollution.
The atmospheric aerosols may be emitted as particles (primary sources) or formed in the atmosphere from gaseous precursors (secondary sources). They have two sources: natural and anthropogenic, as shown in the following table:
Effects of atmospheric aerosols on climatic system (or climatic parameters).
Atmospheric aerosol particles can influence climate change with altering radiative transfer through the atmosphere and the atmospheric water cycle. For the influence of aerosols on climate, the best easily understood mechanism is by directly scattering and absorbing incoming solar radiation and long-wave radiation, thus altering the radiative balance of the earth-atmosphere system. This effect is defined as the direct effect of the atmospheric aerosols. For example scattering incoming solar radiation by sulphate may aerosols increase the Earth's albedo, thereby cooling the atmosphere and the surface; absorption of solar radiation by soot (black carbon) may cool the surface while heating the atmosphere. Direct aerosol effect is primarily a short-wave forcing process and the absorbtion of the long-wave radiation is believed to be small for anthropogenic aerosols other than soot.

下一页