Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry

TLDR

Vegetation is a major source of reactive carbon VOCs that shape tropospheric chemistry, influence oxidant formation, balance the carbon cycle, and contribute to acidic deposition, with isoprene and monoterpenes dominating but oxidized alcohols also emitted. The review examines terrestrial vegetation VOC sources, the biochemical processes driving their emissions, and the subsequent atmospheric chemistry of these compounds. Global annual VOC emissions are estimated at 500–825 Tg yr⁻¹.

Abstract

Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr −1 . The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed.