My work focuses on developing methods for determining sources and sinks of greenhouse gases and ozone depleting substances. I carry out this work in collaboration with researchers around the world through the Advanced Global Atmospheric Gases Experiment (AGAGE), a global monitoring network that measures over 40 trace gases at high frequency and precision. I use models of atmospheric chemistry and transport to determine emissions and sinks of atmospheric gases using the AGAGE measurements. I am the PI of the NERC higlight topic "Detection and Attribution of Regional Emissions in the UK (DARE-UK)" and the NERC Digital Environment project "Hub for Greenhouse Gas data Science (HUGS)". I am a co-of the NERC highlight topic MOYA, investigating the global methane budget, and co-I of the London GHG project. I am a lead author of the 2018 World Meteorological Organisation Scientific Assessment of Ozone Depletion.