Molecular insights into new particle formation across urban and polar environments

Brean, James (2021). Molecular insights into new particle formation across urban and polar environments. University of Birmingham. Ph.D.

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New particle formation (NPF) is a process involving formation of thermodynamically stable molecular clusters and their subsequent growth to larger sizes. NPF modulates the earth’s radiative budget and poses potentially significant health effects, however, the mechanisms driving NPF globally are still uncertain due to limited molecular scale measurements. Urban measurements in both Beijing and Barcelona show highly oxygenated multifunctional organic molecules in high mixing ratios, arising primarily from anthropogenic VOC precursors. Efficient autoxidation due to high temperatures is offset by rapid peroxy radical termination due to high NO\(_x\) mixing ratios. Nucleation is seen to proceed by the nucleation of sulphuric acid, alkylamines, and HOMs in conjunction in Barcelona. An investigation of these mechanisms in the remote polar environment of the Antarctic Peninsula shows nucleation driven by sulphuric acid and amines, with elevations to both the sulphuric acid precursors and amines arising from the melt of sea ice. Particle formation rates are around two orders of magnitude more rapid in the urban environment than in the polar, and particle growth rates are around a single order of magnitude greater. This thesis demonstrates underappreciated roles of both anthropogenic VOC emissions in urban NPF and amine sources in polar regions in facilitating efficient NPF.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Licence: All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Life & Environmental Sciences
School or Department: School of Geography, Earth and Environmental Sciences, Department of Earth and Environmental Sciences
Funders: Natural Environment Research Council
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Q Science > QD Chemistry


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