My PhD research focused on Atmospheric Chemistry, consisting of laboratory studies and field measurements of trace gas and aerosol composition using online mass spectrometry. My PhD thesis is available here.
Air Pollution in Megacities
I conducted field measurements as part of the NERC-Newton Fund Joint UK-China Atmospheric Pollution and Human Health (APHH) project in urban Beijing during winter 2016 and summer 2017. A summary of the findings from this field study can be found in the APHH Beijing Final Report.
We used an Aerodyne/Tofwerk time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) with iodide ionisation coupled with a filter inlet for gases and aerosols (FIGAERO) to study both trace gas and particle phase chemical composition.
My analysis of measurements using positive matrix factorisation (PMF) is published in the Royal Society of Chemistry’s Faraday Discussions:
This work has also contributed to several co-authored publications which focus on the chemistry of the urban atmosphere:
Production of N2O5 and ClNO2 in summer in urban Beijing, China
Intercomparison of nitrous acid (HONO) measurement techniques in a megacity (Beijing)
Strong anthropogenic control of secondary organic aerosol formation from isoprene in Beijing
Low-NO atmospheric oxidation pathways in a polluted megacity
Strong anthropogenic control of secondary organic aerosol formation from isoprene in Beijing
Aerosol from Plant Emissions
Emissions from plants and vegetation are important for aerosol formation on a global scale. Their emission speciation and magnitude is diverse around the world and it remains unclear if the most widely studied compounds are representative of real plant emissions.
This study was led by the University of California Irvine in collaboration with Aerodyne Research Inc. and focused on the atypical emission profile of california sage plants and their oxidation to form organic aerosol. I recently published on the findings of this study:
Aromatic Oxidation Chemistry
Aromatic hydrocarbons are emitted from human activity in urban and industrialised areas and can influence tropospheric chemistry and lead to secondary organic aerosol (SOA) formation.
There remain uncertainties in their oxidation chemistry and aerosol formation. I designed and led a study to improve our understanding of this using a suite of mass spectrometry based techniques at Aerodyne Research Inc. during the summer of 2017, in collaboration with The University of York and Fudan University. I recently published on the findings of this study:
Evaluation of the chemical composition of gas- and particle-phase products of aromatic oxidation
I also contributed to several co-authored publications focusing on different aspects of aromatic oxidation chemistry:
Airborne Mass Spectrometry
During January 2019 I took part in the NERC-funded Methane Observations and Yearly Assesments (MOYA) project in Uganda, which involved running the ToF-CIMS aboard the FAAM Research Aircraft.
Though focused on the global methane emission budget, this campaign allowed for measurements of biomass burning and atmospheric composition in poorly investigated regions of Uganda, Tanzania and Zambia. I contributed to a recent publication detailing results from this project: