Research Fellows Directory
Dr Kirsti Ashworth
My research explores the fundamental processes behind the exchange of reactive gases and particles from the vegetated land surface and the atmosphere, focusing on trees and woodland in and around urban areas. Trees are often planted in these areas for reasons of aesthetics, to enhance human health and well-being and to improve climate as they reduce temperature and wind speed locally. By taking in a substantial proportion of the carbon dioxide released from human activities they also confer long-term benefits to climate. Less well known and understood, however, is that vegetation especially trees also emit to the atmosphere a large quantity of hydrocarbons (equivalent to the combined weight of every man, woman and child on the planet each year). These compounds react rapidly, and in regions with high levels of nitrogen oxides (released during the combustion process in transportation and industry) their oxidation leads to the formation of ozone and aerosol particles. These not only affect the climate but are also key air pollutants with strict limits set by the World Health Organisation.
Exposure to poor air quality results in nearly 5 million deaths around the world each year, as well as damaging vegetation reducing global crop yields by an estimated 20%. My work combines measurements made during controlled laboratory experiments, field trials and in-situ monitoring with computer-based models of the emission, chemical reactions, atmospheric mixing and deposition back to the land surface of the air pollutants ozone, particles and nitrogen dioxide, and the reactive hydrocarbons that form them. This allows me to improve both our understanding of and ability to simulate their distribution, quantity and fate in the atmosphere. This will enable us as a society to better understand how urban forests interact with the atmosphere offering us a potential way to improve air quality, not only improving human health in urban areas but increasing food supply in the future.
Interests and expertise (Subject groups)