Wilson, Samuel ORCID: 0000-0002-0117-5545
(2025)
Understanding the Role of Vehicle Emissions as Part of Urban Air Pollution Source Complexity.
PhD thesis, University of York.
Abstract
Air pollution is a major global challenge, with urban areas disproportionately affected due to high population densities and elevated pollutant concentrations. Despite advances in vehicle technology and stringent emissions legislation, road transport remains a significant source of urban air pollution. This thesis explores road transport emissions using individual vehicle measurements made with fast-response techniques to improve understanding of the complex relationship between these emissions and urban air quality. Analysis of over 600,000 remote sensing measurements from across the United Kingdom (UK) revealed decade-long trends in vehicular emissions of carbon monoxide, hydrocarbons, ammonia (NH3), and nitrogen oxides (NOx = NO + NO2). The impact of national policies promoting diesel fuel use on air quality was evaluated, revealing that these policies led to an excess of 721 kt of NOx emissions in the UK. Rising NH3 emissions from an increasing number of gasoline and hybrid vehicles were also highlighted as a growing concern. Point sampling measurements demonstrated that vehicle exhaust location and aerodynamic properties influence near-road pollutant dispersion and concentrations, which suggests that targeting factors beyond direct emissions reduction could improve urban air quality. For example, relocating passenger car exhausts could reduce roadside pollutant concentrations by up to a third. Electric vehicles were found to disperse pollutants from fossil-fuelled vehicles, reducing near-road pollutant concentrations. Mobile monitoring in London, UK, showed that diesel and gasoline particulate filters effectively reduce particulate matter (PM) emissions, even under highly congested conditions. However, high-emitting vehicles and construction sites were identified as key sources of urban PM, indicating that non-vehicular sources are becoming increasingly important contributors to urban air pollution amidst a broader reduction in vehicle emissions.
Metadata
Supervisors: | Carslaw, David and Farren, Naomi and Lee, James |
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Related URLs: | |
Keywords: | vehicle emissions, urban air pollution, air quality, nitrogen oxides, nox, traffic-related air pollution, trap, particulate matter, pm, pm2.5, pm10, remote sensing, point sampling, mobile monitoring, fast-response |
Awarding institution: | University of York |
Academic Units: | The University of York > Chemistry (York) |
Depositing User: | Mr Samuel Wilson |
Date Deposited: | 14 Jul 2025 14:51 |
Last Modified: | 14 Jul 2025 14:51 |
Open Archives Initiative ID (OAI ID): | oai:etheses.whiterose.ac.uk:37152 |
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