Direct Studies of Peroxy Radical Autoxidation Reactions

Biogenic volatile organic compounds (BVOCs) play a crucial role in climate by setting the background levels of aerosol in the atmosphere. Aerosols directly and indirectly interact with solar radiation and affect climate. BVOCs also play a crucial role in air quality through forming secondary pollutants like O3 which adversely affect humans and plants. Peroxy radicals (RO2) are key intermediates involved in these physio-chemical processes and are formed with myriad structural differences which are predicted to greatly affect their reactivity and pathways to form aerosols and O3. However, until the recent breakthroughs in near infrared cavity ring-down spectroscopy understanding the distribution of RO2 structures and reactivity, and so the effects on aerosols and O3, was impossible. Here we propose a combined laboratory and Earth system modelling project which will determine the key physio-chemical properties of RO2 from the most important BVOCs (isoprene and alpha-pinene) and integrate this knowledge through the development and incorporation of chemical mechanisms that will be used to simulate the climate impacts of BVOCs more faithfully than ever possible before.

The results from this project will be of direct benefit to academic researchers in atmospheric and physical sciences and policy makers planning for the environmental and climate changes in the near and long-term future. This project will enable Dr Rabi Chhantyal Pun to start a new research program focused on laboratory photochemistry at the University of Nottingham, with modelling support from Dr Alexander Archibald at the University of Cambridge. It will also provide state-of-art laboratory and atmospheric chemistry training for a new postdoctoral research associate.