过去二十年大气中羟基自由基大幅变化的证据。
Evidence for substantial variations of atmospheric hydroxyl radicals in the past two decades.
作者信息
Prinn R G, Huang J, Weiss R F, Cunnold D M, Fraser P J, Simmonds P G, McCulloch A, Harth C, Salameh P, O'Doherty S, Wang R H, Porter L, Miller B R
机构信息
Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
出版信息
Science. 2001 Jun 8;292(5523):1882-8. doi: 10.1126/science.1058673. Epub 2001 May 3.
The hydroxyl radical (OH) is the dominant oxidizing chemical in the atmosphere. It destroys most air pollutants and many gases involved in ozone depletion and the greenhouse effect. Global measurements of 1,1,1-trichloroethane (CH3CCl3, methyl chloroform) provide an accurate method for determining the global and hemispheric behavior of OH. Measurements show that CH3CCl3 levels rose steadily from 1978 to reach a maximum in 1992 and then decreased rapidly to levels in 2000 that were lower than the levels when measurements began in 1978. Analysis of these observations shows that global OH levels were growing between 1978 and 1988, but the growth rate was decreasing at a rate of 0.23 +/- 0.18% year(-2), so that OH levels began declining after 1988. Overall, the global average OH trend between 1978 and 2000 was -0.64 +/- 0.60% year(-1). These variations imply important and unexpected gaps in current understanding of the capability of the atmosphere to cleanse itself.
羟基自由基（OH）是大气中主要的氧化化学物质。它能破坏大多数空气污染物以及许多与臭氧层损耗和温室效应有关的气体。对1,1,1 - 三氯乙烷（CH3CCl3，甲基氯仿）的全球测量为确定OH在全球和半球范围的行为提供了一种准确方法。测量结果显示，CH3CCl3的水平从1978年开始稳步上升，在1992年达到最高值，随后迅速下降，到2000年时已低于1978年测量开始时的水平。对这些观测数据的分析表明，1978年至1988年间全球OH水平在上升，但增长率以每年-0.23±0.18%（年-2）的速度下降，因此OH水平在1988年后开始下降。总体而言，1978年至2000年间全球平均OH趋势为每年-0.64±0.60%（年-1）。这些变化表明，目前对大气自我净化能力的理解存在重要且意想不到的差距。
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