Quantifying the impact of tropospheric chlorine oxidation chemistry
This project addresses a fundamental and yet highly unconstrained question in atmospheric chemistry: What is the impact of atomic chlorine on the composition of the troposphere?
Gas phase oxidants control the concentrations of important climate and air pollutants such as methane, ozone and particles. Accurate representation of oxidation chemistry in computational models is paramount to our ability predict and understand past, present and future changes to the Earth system. Over recent decades there have been continual suggestions that the chlorine atom may be a significant tropospheric oxidant, but a lack of observations capable of constraining its chemistry mean that its role remains highly uncertain. Without these underpinning observations, our understanding of atmospheric oxidation and thus our ability to develop effective and timely policies to address air quality and climate change is compromised.
This project will provide a step-change in our understanding of atmospheric chlorine chemistry. Capitalising on recent technology advances, two innovative instruments capable of definitively constraining chlorine atom sources and sinks will be developed. These instruments will be deployed at three chemically contrasting locations (Cape Verde, coastal Netherlands and central Germany), generating the first comprehensive dataset on tropospheric chlorine atom production and loss. These data will be used to challenge the state-of-the-science representation of chlorine chemistry in atmospheric chemistry models. Ultimately this work will advance our understanding of the fundamental chemistry occurring in the atmosphere and help to direct developments in the next generation of air quality and climate models.