Date of Award

2018

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Environmental Engineering (PhD)

Administrative Home Department

Department of Geological and Mining Engineering and Sciences

Advisor 1

Shiliang Wu

Committee Member 1

Judith Perlinger

Committee Member 2

Hugh Gorman

Committee Member 3

Noel Urban

Abstract

Wildfires are episodic disturbances that exert a significant influence on the Earth system. They emit substantial amounts of atmospheric pollutants, which can impact atmospheric chemistry/composition and the Earth’s climate at the global and regional scales. This work presents a collection of studies aimed at better estimating wildfire emissions of atmospheric pollutants, quantifying their impacts on remote ecosystems and determining the implications of 2000s-2050s global environmental change (land use/land cover, climate) for wildfire emissions following the Intergovernmental Panel on Climate Change (IPCC) A1B socioeconomic scenario.

A global fire emissions model is developed to compile global wildfire emission inventories for major atmospheric pollutants [greenhouse gases (CO2, CH4, N2O), air pollutants and tropospheric O3 precursors (nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOCs) (alkanes, alkenes)), aerosols and their precursors (particulate matter (PM2.5), black carbon (BC), organic carbon (OC), sulfur dioxide (SO2)) and mercury (Hg)] and quantify the impacts of 2000s-2050s global change. The estimated Hg wildfire emissions (2000s) are used in a global chemical transport model (GEOS-Chem) to determine the contribution of wildfire emissions to Hg pollution in the Arctic.

Significant perturbations to wildfire emissions of atmospheric pollutants in the context of global change are estimated, mainly driven by the projected changes in climate, land use/land cover and in the case of Hg, anthropogenic emissions as well. A continuing increase in anthropogenic influence on wildfires in the coming decades is predicted. Greater human occupation of the African continent and increase in cropland coverage cause significant declines in wildfire emissions of atmospheric pollutants from the continent. Anthropogenic factors play an important role in the changes in emissions from other continents as well. Future changes in climate and land cover contribute to significant increases in global emissions for all the species.

Wildfires are estimated to contribute 10% of global annual deposition to the Arctic with boreal fires in Asia contributing the most. Wildfires in Eurasia contribute 5.3% of annual Hg deposition followed by Africa (2.5%) and North America (1%). Wildfires contribute to Arctic Hg deposition throughout the year with the highest deposition occurring during the boreal fire season.

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