Isoprene Emissions, Oxidation Chemistry and Environmental Impacts

Isoprene emissions can affect the oxidizing capacity of the atmosphere and are likely to increase with an increase in the world’s biomass. The emission of isoprene is strongest in tropical forested regions, suggesting a major portion of tropospheric chemistry occurs in the tropics. As well as defore...

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Main Authors: M. Anwar H. Khan, Rayne Holland, Charlotte Mould, Asan Bacak, Carl J. Percival, Dudley E. Shallcross
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Atmosphere
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Online Access:https://www.mdpi.com/2073-4433/16/3/259
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author M. Anwar H. Khan
Rayne Holland
Charlotte Mould
Asan Bacak
Carl J. Percival
Dudley E. Shallcross
author_facet M. Anwar H. Khan
Rayne Holland
Charlotte Mould
Asan Bacak
Carl J. Percival
Dudley E. Shallcross
author_sort M. Anwar H. Khan
collection DOAJ
description Isoprene emissions can affect the oxidizing capacity of the atmosphere and are likely to increase with an increase in the world’s biomass. The emission of isoprene is strongest in tropical forested regions, suggesting a major portion of tropospheric chemistry occurs in the tropics. As well as deforestation and reforestation having a direct impact on the world’s climate through land cover, there is also an indirect environmental impact (e.g., global warming, air pollution) through the resulting change in isoprene emissions. Previously, incomplete understanding of isoprene oxidation chemistry caused a model-measurement breakdown for concentrations of HO<sub>x</sub> radicals observed over certain low-NO<sub>x</sub> regions, such as the pristine Amazon rainforest. Over the last decade, however, understanding of isoprene oxidation chemistry has been vastly improved. Numerous research studies have provided evidence for the involvement of 1,6-H and 1,5-H shift reactions in the isoprene oxidation mechanism, which increases the level of HO<sub>x</sub> recycling that occurs. As well as helping to reduce the model-measurement breakdown observed, the updated isoprene oxidation mechanism affects the tropospheric burdens of other species, including carbon monoxide (CO), methane (CH<sub>4</sub>), ozone (O<sub>3</sub>), organic peroxides (ROOH), secondary organic aerosol (SOA), and organic nitrates (RONO<sub>2</sub>). There are still gaps in the understanding of the impacts and oxidation chemistry of isoprene emissions, which this literature review identifies and discusses. In the future, there is still much scope for further research, including modeling future reforestation scenarios with isoprene emissions and their impacts on both global and regional scales.
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spelling doaj-art-d4578846a75841efbfc32ca4745d77852025-08-20T02:42:38ZengMDPI AGAtmosphere2073-44332025-02-0116325910.3390/atmos16030259Isoprene Emissions, Oxidation Chemistry and Environmental ImpactsM. Anwar H. Khan0Rayne Holland1Charlotte Mould2Asan Bacak3Carl J. Percival4Dudley E. Shallcross5School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UKSchool of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UKSchool of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UKAnkara University Cancer Research Institute, Balkiraz Mahallesi, Mamak Caddesi No:1/8, 06620 Mamak, Ankara, TurkeyJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109, USASchool of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UKIsoprene emissions can affect the oxidizing capacity of the atmosphere and are likely to increase with an increase in the world’s biomass. The emission of isoprene is strongest in tropical forested regions, suggesting a major portion of tropospheric chemistry occurs in the tropics. As well as deforestation and reforestation having a direct impact on the world’s climate through land cover, there is also an indirect environmental impact (e.g., global warming, air pollution) through the resulting change in isoprene emissions. Previously, incomplete understanding of isoprene oxidation chemistry caused a model-measurement breakdown for concentrations of HO<sub>x</sub> radicals observed over certain low-NO<sub>x</sub> regions, such as the pristine Amazon rainforest. Over the last decade, however, understanding of isoprene oxidation chemistry has been vastly improved. Numerous research studies have provided evidence for the involvement of 1,6-H and 1,5-H shift reactions in the isoprene oxidation mechanism, which increases the level of HO<sub>x</sub> recycling that occurs. As well as helping to reduce the model-measurement breakdown observed, the updated isoprene oxidation mechanism affects the tropospheric burdens of other species, including carbon monoxide (CO), methane (CH<sub>4</sub>), ozone (O<sub>3</sub>), organic peroxides (ROOH), secondary organic aerosol (SOA), and organic nitrates (RONO<sub>2</sub>). There are still gaps in the understanding of the impacts and oxidation chemistry of isoprene emissions, which this literature review identifies and discusses. In the future, there is still much scope for further research, including modeling future reforestation scenarios with isoprene emissions and their impacts on both global and regional scales.https://www.mdpi.com/2073-4433/16/3/259ozoneAmazonclimate changedeforestationreforestationoxidation mechanism
spellingShingle M. Anwar H. Khan
Rayne Holland
Charlotte Mould
Asan Bacak
Carl J. Percival
Dudley E. Shallcross
Isoprene Emissions, Oxidation Chemistry and Environmental Impacts
Atmosphere
ozone
Amazon
climate change
deforestation
reforestation
oxidation mechanism
title Isoprene Emissions, Oxidation Chemistry and Environmental Impacts
title_full Isoprene Emissions, Oxidation Chemistry and Environmental Impacts
title_fullStr Isoprene Emissions, Oxidation Chemistry and Environmental Impacts
title_full_unstemmed Isoprene Emissions, Oxidation Chemistry and Environmental Impacts
title_short Isoprene Emissions, Oxidation Chemistry and Environmental Impacts
title_sort isoprene emissions oxidation chemistry and environmental impacts
topic ozone
Amazon
climate change
deforestation
reforestation
oxidation mechanism
url https://www.mdpi.com/2073-4433/16/3/259
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