Fig. 1: Organic carbon exchange of major isoprene photooxidation products between the biosphere and the atmosphere on a global scale.
From: Rapid conversion of isoprene photooxidation products in terrestrial plants
Under low nitrogen oxide (NOx) conditions 1,2-ISOPOOH is preferentially formed, producing epoxides that then react with OH and contribute to aerosol formation74. At high NOx the production of carbonyls such as methyl vinyl ketone (MVK) supports ozone formation5 (panel a). Dry-deposited 1,2-ISOPOOH and MVK (panel b) is instantaneously detoxified within the plant leaf (panels c, d) via the enzyme alkenal/one oxidoreductase (AOR). EC measurements in natural forest settings confirm our modified GEOS-Chem model results (indicated with *) that ~6.5 Tg methyl ethyl ketone (MEK) (corresponding to 1.5% of the isoprene source) is emitted into the atmosphere in this way. This is the single largest known MEK source on a global scale. †Values from ref. 75. ‡Values from ref. 7.
