Atmospheric oxidation capacity sustained by a tropical forest

被引：673

作者：

Lelieveld, J. ^{[1
]}

Butler, T. M. ^{[1
]}

Crowley, J. N. ^{[1
]}

Dillon, T. J. ^{[1
]}

Fischer, H. ^{[1
]}

Ganzeveld, L. ^{[1
]}

Harder, H. ^{[1
]}

Lawrence, M. G. ^{[1
]}

Martinez, M. ^{[1
]}

Taraborrelli, D. ^{[1
]}

Williams, J. ^{[1
]}

机构：

[1] Max Planck Inst Chem, D-55128 Mainz, Germany

来源：

NATURE | 2008年 / 452卷 / 7188期

关键词：

D O I：

10.1038/nature06870

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Terrestrial vegetation, especially tropical rain forest, releases vast quantities of volatile organic compounds (VOCs) to the atmosphere(1-3), which are removed by oxidation reactions and deposition of reaction products(4-6). The oxidation is mainly initiated by hydroxyl radicals (OH), primarily formed through the photodissociation of ozone(4). Previously it was thought that, in unpolluted air, biogenic VOCs deplete OH and reduce the atmospheric oxidation capacity(5-10). Conversely, in polluted air VOC oxidation leads to noxious oxidant build-up by the catalytic action of nitrogen oxides(5-10) (NOx = NO + NO2). Here we report aircraft measurements of atmospheric trace gases performed over the pristine Amazon forest. Our data reveal unexpectedly high OH concentrations. We propose that natural VOC oxidation, notably of isoprene, recycles OH efficiently in low-NOx air through reactions of organic peroxy radicals. Computations with an atmospheric chemistry model and the results of laboratory experiments suggest that an OH recycling efficiency of 40-80 per cent in isoprene oxidation may be able to explain the high OH levels we observed in the field. Although further laboratory studies are necessary to explore the chemical mechanism responsible for OH recycling in more detail, our results demonstrate that the biosphere maintains a remarkable balance with the atmospheric environment.

引用

页码：737 / 740

页数：4

共 29 条

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