Biogenic Hydrocarbons

Although it has been known for more than half a century that plants release a plethora of non-methane hydrocarbons (NMHCs), it was not until the mid-1980s that scientists firmly established the links between ozone formation/destruction and ambient NMHCs. Owing to their high reactivity, it is now well known that NMHCs can augment ozone formation in environments rich in nitrogen oxides. In jurisdictions such as the northeastern part of North America, this is a serious environmental issue as summer-time ozone levels frequently exceed the National Ambient Air Quality Standard set by the U.S. Environmental Protection Agency. I have conducted research to separate the contribution of biogenic precursors to ozone formation. My most active research area concerns field and theoretical investigations involving turbulent transport theory and chemical processing of biogenic NMHCs inside and above forests. My early work on this topic involved the development of measurement protocols to investigate the environmental and vegetation controls on hydrocarbon emissions at foliage and plant canopy levels. The fieldwork I conducted in the temperate and boreal forests of Canada led me to develop and test one-dimensional canopy models to scale hydrocarbon emissions from single leaves to the canopy dimension. Theoretical studies showed that in remote environments (where nitrogen oxide levels are negligible) these scaling processes yield credible results provided that the variation of the physical environment within the modeling domain is correctly prescribed.  Hydrocarbon emissions depend on leaf temperature and light levels impinging on foliage control.  I have contributed with research to develop and test models to describe the physical environment inside forest canopies, and thus estimate hydrocarbon emisions and chemical processing. These models are based on the state-of-the-science turbulent transport and radiative transfer theory, which has been integrated and adopted to address my NMHC research. Much of my recent research involves the understanding of the seasonal controls on biogenic production from deciduous forests.  Lately, we have been investigating the aerosol yields from hydrocarbon oxidation.  The impetus of this latest research is to quantify the radiative forcing by phytogenic aerosols and to discern the influence of phytogenic aerosols on cloud formation processes. The hydrocarbon research is being carried in places such as Canada, Brazil, the Piedmont of Virginia, the Florida Everglades and New Mexico.

Document Actions