RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere)

Lead Research Organisation: University of Cambridge
Department Name: Chemistry

Abstract

There is now a significant and increasing body of evidence that night time chemistry, driven primarily by the nitrate radical NO3, plays a significant role in governing the composition of the troposphere. Recent findings show that very high concentrations of NO3 are present away from the Earth's surface. In polluted environments, the main sinks are abundant but this is also where its formation may be most rapid and hence the NO3 turnover time is very fast. The importance of this behaviour is not as yet clearly understood, yet it may have a very large impact on atmospheric chemistry and ozone formation, regional transport and transformation of oxidised nitrogen and hence acidification and eutrophication, and may also significantly add to the regional burden of ammonium nitrate particulate, which has increasing climatic importance. To understand and predict these phenomena correctly there is a need to quantify the basic chemical processes controlling NO3 and its removal from the atmosphere; the impact of NO3 chemistry on volatile organic carbon chemistry and as a pathway for radical formation and propagation; its heterogeneous chemistry and its impact on the aerosol burden and composition; its influence on ozone formation on regional and global scales and its mediation of the atmospheric lifecycle of oxidised nitrogen. A consortium project is proposed that addresses these coupled questions using a combined programme of instrument development, airborne measurement, detailed process modelling, and regional and global modelling. The principal deliverables will be: a) Enhancements to the instrumental capability of the FAAM aircraft to include measurements of NO3 and N2O5. b) Comprehensive measurements of night time radicals, their sources and sinks, and aerosol composition in the boundary layer and free troposphere in a range of conditions. d) Quantification of the key processes which control night-time chemical processes. e) Assessment of the impacts of night-time chemistry on regional scales. f) An assessment of the global impacts of night-time chemistry in the current and future atmospheres.

Publications

10 25 50

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Carpenter L (2015) A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer in Journal of Atmospheric Chemistry

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Ouyang B (2013) NO3 radical production from the reaction between the Criegee intermediate CH2OO and NO2. in Physical chemistry chemical physics : PCCP

 
Description Research specific to this project: Increased understanding of the interaction of aerosol chemical composition on N2O5 uptake. The analysis points to the important role played by ammonium nitrate and particulate water content in controlling the heterogeneous uptake of N2O5 in NW Europe. Detection of an active nighttime chemistry, including the generation of HOx species and a range of nitrate species under different chemical conditions. The results will improve understanding of the NOx budget of the troposphere in the UK European sector, and hence the global O3 budget. Wider significance: Related to this work, there have been a number of additional/anciliary activities Firstly there have been several papers outlining the now proven designs for instruments for measuring both radical species (NO3, N2O5 - the BBCEAS instrument) and an LIF instrument to measure a range of NOx containing species. These are important papers outline capability for future experiments, and have lead to the BBCEAS being deployed as part of the NERC/USA coordinated CAST campaign to measure IO in the low troposphere. The BBCEAS instrument has also been used for a series of related laboratory studies, most recently on the role of Criegee intermediates in night-time chemistry. Finally, the work has provided the backdrop for general studies of the fundamental limitations of cavity enhanced techniques.
Exploitation Route Improved understanding of the tropospheric O3 budget and its likely future change is an important aspect of understanding the impacts of climate change and once incorporated into assessment reports is thus of interest to the wider non-academic community. Improved scientific understanding of the tropospheric O3 budget, understanding past changes as well as future climate related changes. The BBCEAS instrument is now integrated into the NERC CAST project (Harris et al., 2014). Several papers have been published, and a series of others are in the final stages of preparation as part of a joint Atmospheric Measurement Technology/Atmospheric Chemistry and Physics special issue.
Sectors Environment,Transport,Other

 
Description Directed International
Amount £300,000 (GBP)
Funding ID NE/N007115/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2016 
End 01/2020
 
Description Participation in the NERC CAST campaign 
Organisation University of Cambridge
Department Department of Genetics
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual expertise associated with the adaptation of the broadband cavity ring down instrument developed under the RONOCO the campaign award to measure IO for the NERC funded CAST campaign.
Collaborator Contribution An upper limit for IO concentrations was obtained during the campaign at a range of altitudes within the boundary layer in regions across the pacific ocean.
Impact There have been several related publications
Start Year 2014
 
Description Participation in the NERC CAST campaign 
Organisation University of York
Department Department of Electronics
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual expertise associated with the adaptation of the broadband cavity ring down instrument developed under the RONOCO the campaign award to measure IO for the NERC funded CAST campaign.
Collaborator Contribution An upper limit for IO concentrations was obtained during the campaign at a range of altitudes within the boundary layer in regions across the pacific ocean.
Impact There have been several related publications
Start Year 2014