Atmospheric Emissions from the UK Oil and Gas Industry

Since 2014, oil and gas (O&G) production in the UK has experienced a resurgence, increasing by 20%. However, increased development has sparked environmental concerns surrounding the industry. At all stages of the O&G life-cycle harmful air pollutants are released, negatively impacting air quality and climate at the local, regional and global scale. However, the full range of emissions remains relatively unknown due to the vast number of potential sources and lack of observational data. The current inventories are generally limited by self-reporting and inaccurate emission factors, which subsequently hinders the assessment of human health and climate risks. This thesis addresses these issues by providing valuable measurement data relating to both onshore and offshore O&G production in the UK. First, an extensive analysis of airborne trace gas measurements over four regions of the North Sea, where few observations currently exist, is presented. Volatile organic compound (VOC) enhancement ratios were utilised to indicate the prevalence of O&G production as the key source of VOCs in these regions and to investigate the VOC composition related to the type of fossil-fuel product. Second, a mass balance analysis was applied to airborne measurements of plumes downwind of O&G
platforms to quantify emissions from single facilities. A general underestimation in relation to the reported emissions of both methane and total VOCs was found. Distinct enhancements of VOCs, not reflected in the bottom-up reporting were concurrent with oil loading operations, identifying a key area for review in the current methodology. Finally, ground-based monitoring at a UK shale gas site, combined with a machine learning technique, revealed well-pad preparation as a significant, understudied source of nitrogen oxides. This demonstrated a need to consider all stages in the well life-cycle in order to gain a true understanding of the impacts from an air quality perspective.