Research Fellows Directory
Professor Charles Hewitt
Most, but not all, terrestrial plants produce volatile organic compounds (VOCs). They do so for a variety of reasons, including providing protection against abiotic and biotic stresses and for plant to plant and plant to insect communication. As a result of their high vapour pressures, these compounds are rapidly lost from the plant surface and emitted into the atmosphere. Some are highly reactive in the gas phase, and these compounds are believed to play major roles in the physics and chemistry of the atmosphere. They mediate in the formation of ozone, so controlling the oxidizing capacity of the atmosphere, which in turn controls the lifetime of methane and other radiatively active “greenhouse” gases. They may also form particles, which may influence the radiative balance of the atmosphere.
In order to better understand the behaviour of ozone and particles in the lower atmosphere we need to improve our understanding of VOC emissions and chemistry. Our focus is on tropical regions, since that is where the biosphere produces most VOCs, and where most rapid and drastic land use change is occurring, but we also work on temperate biomes. In particular we have shown that large scale production of biofuel crops in Europe will significantly alter ground level ozone concentrations in Europe, with detrimental impacts on human mortality and crop yields. This has significant policy implications, since the control of the priority pollutant ozone is hugely expensive.
Interests and expertise (Subject groups)