Isoprene oxidation and OH recycling
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
The surface temperature of the Earth varies dramatically from polar regions through to equatorial ones. There are many factors that give rise to this temperature variation but the main ones are; the amount of heat energy arriving at the surface from the sun (which is smaller at the poles than the equator), the reflectivity of the Earth (called the albedo) which determines how much of the sun's energy is simply reflected back to space (and includes clouds and ice at the surface) which cool the surface and the amount of greenhouse gases in the atmosphere which act as a blanket around the Earth (preventing heat from the Earth from escaping to space) and warm the surface up.
Plants play a vital role in the Earth system, converting carbon dioxide and water into sugars and oxygen (essential for life) during photosynthesis. They also absorb a range of pollutants on their surfaces and are planted in urban areas in part to reduce the levels of particulate matter. However, plants also release a cocktail of chemicals for a variety of reasons, e.g. attracting pollinators, defence against predators and protection against a variety of pollutants such as ozone. The hydroxyl radical (OH) is a species produced in the atmosphere that acts like a chemical detergent, mopping up pollutants and cleansing the atmosphere. It was believed that these chemicals released by plants suppressed the hydroxyl radical and therefore would increase the level of greenhouse gases. However, recent measurements of the level of OH in the tropics suggest that this idea is wrong and that these chemicals actually lead to OH recycling.
If this is correct then plants and in particular those in tropical regions, will be playing a significant role in off-setting climate change. If the recycling of OH is correct then these plant emissions are leading to a reduction in the amount of greenhouse gases present in the atmosphere.
In addition, it is believed that these emissions may also lead to aerosol species that will help to form cloud and further cool the planet. Therefore, this combination of effects could be extremely important to our understanding of the Earth's climate (past, present and future). It will also of course have important implications for forest ecosystems, the enhanced negative impact of deforestation in tropical regions and land-use strategies in general.
A variety of scientists have speculated about how these chemicals may be leading to a recycling of OH, some based on laboratory experiments. However, the ones that appear to have the biggest potential impact and may resolve, at least in part, the discrepancy between measurements and computer simulations, are based on computer based calculations themselves. Therefore, it is vital that these theoretical studies be verified in the laboratory. These reactions are difficult to study and so we propose to add tags (swapping hydrogen for deuterium)to some of the chemicals we wish to study so that we can follow the reaction pathway more easily. We will use a range of detectors in concert with both a flow system and a static reaction chamber. Both systems will allow us to stufy different aspects of the chemical system. The detectors we will use include mass spectrometry (where we identify compounds by their weight) and spectroscopy (where we identify compounds by the amount of a specific colour of light that they absorb). These instruments have been developed at the two Universities involved (Bristol and Manchester) and allow them to be uniquely placed to be one of the few teams in the world able to carry out these studies.
Plants play a vital role in the Earth system, converting carbon dioxide and water into sugars and oxygen (essential for life) during photosynthesis. They also absorb a range of pollutants on their surfaces and are planted in urban areas in part to reduce the levels of particulate matter. However, plants also release a cocktail of chemicals for a variety of reasons, e.g. attracting pollinators, defence against predators and protection against a variety of pollutants such as ozone. The hydroxyl radical (OH) is a species produced in the atmosphere that acts like a chemical detergent, mopping up pollutants and cleansing the atmosphere. It was believed that these chemicals released by plants suppressed the hydroxyl radical and therefore would increase the level of greenhouse gases. However, recent measurements of the level of OH in the tropics suggest that this idea is wrong and that these chemicals actually lead to OH recycling.
If this is correct then plants and in particular those in tropical regions, will be playing a significant role in off-setting climate change. If the recycling of OH is correct then these plant emissions are leading to a reduction in the amount of greenhouse gases present in the atmosphere.
In addition, it is believed that these emissions may also lead to aerosol species that will help to form cloud and further cool the planet. Therefore, this combination of effects could be extremely important to our understanding of the Earth's climate (past, present and future). It will also of course have important implications for forest ecosystems, the enhanced negative impact of deforestation in tropical regions and land-use strategies in general.
A variety of scientists have speculated about how these chemicals may be leading to a recycling of OH, some based on laboratory experiments. However, the ones that appear to have the biggest potential impact and may resolve, at least in part, the discrepancy between measurements and computer simulations, are based on computer based calculations themselves. Therefore, it is vital that these theoretical studies be verified in the laboratory. These reactions are difficult to study and so we propose to add tags (swapping hydrogen for deuterium)to some of the chemicals we wish to study so that we can follow the reaction pathway more easily. We will use a range of detectors in concert with both a flow system and a static reaction chamber. Both systems will allow us to stufy different aspects of the chemical system. The detectors we will use include mass spectrometry (where we identify compounds by their weight) and spectroscopy (where we identify compounds by the amount of a specific colour of light that they absorb). These instruments have been developed at the two Universities involved (Bristol and Manchester) and allow them to be uniquely placed to be one of the few teams in the world able to carry out these studies.
Planned Impact
The laboratory based kinetic and mechanistic data collected in this proposal on the degradation pathways for the low NOx, OH initiated oxidation of isoprene (after suitable quality control and analysis) will be made available to all users via the websites of both the Manchester and Bristol groups. In addition these data will be described and analysed in a series of research papers that will be submitted to Journals such as Atmospheric Chemistry and Physics, Journal of Geophysical Research and Environmental Science and Technology.
These data will also be used to develop a modified mechanism for low NOx oxidation of isoprene based on both the Master Chemical Mechanism and the Common Representative Intermediates methodologies. These mechanisms will also be available from the groups' websites but also from the main MCM website as well for anyone to use. The MCM (containing the CRI) website provides users with the opportunity to download the mechanism is a variety of different formats, suitable to the users needs. These modified mechanisms will be used in both a regional (trajectory model) and the global model CRI-STOCHEM. The models will be intergrated and compared with available field data to assesses the impact on OH recycling. The results from these integrations will also form the basis for a research paper.
We will attend UK (e.g. university departmental seminar series, Royal Society of Chemistry's Gas-Kinetics meetings, Royal Meteorological Societies Atmospheric Chemistry Group meetings and the R. Met. Soc. annual conference) and international meetings (e.g. EGU and AGU) to present this work in both oral presentations and poster form.
Between the two groups we have active collaborations with a number of UK research groups and Centres (e.g. NERC National Centre for Atmos. Sci., NERC Centre for Ecology and Hydrology) as well as many groups outside the UK. In the course of these collaborations we would give presentations on visits, discuss new data via e-mail etc. and receive feedback.
We already have regular contact with the U.K. Met. Office and DECC (Dept. Energy and Climate Change) through other on-going projects and will update them on progress of this work. Other groups we interact with include, the UK Home Office, DSTL (Porton Down), a range of instrument manufacturers and chemical suppliers and as a matter of course we update them about new work we are undertaking.
We will write a layman's summary of the outcomes of the project and this will be posted on our websites too. In addition we will develop about 3 pages that will be based on Bristol ChemLabS' very successful Dynamic Laboratory Manual. The dynamic web-pages will be directed at a general audience (suitable for average 10 year olds for the basic one and 14 year olds and then 16 year olds for the other two) and will cover the background to atmospheric pollution and climate change.
Through the help of the Bristol ChemLabS' School Teacher Fellow and Science Communicator in Residence, Tim Harrison, this project will give talks heavily populated with lively experiments, called a 'Pollutants' Tale' for secondary school and older (> 11 years old) and 'Gases in the air' for primary school (4-11 years old), at schools, UK science festivals and to general interest groups. We expect to engage with at least 15,000 people directly by the end of this three year project. We will also write at least one article for the journal Science in School, which is read by 130,000 schools, their teachers and students across Europe. Articles we have written on atmospheric chemistry in the past 3-4 years have been downloaded over 250,000 times. These papers have also led to us providing a book chapter of a work on the Earth's Climate.
Our strategy for impact covers; academics and research centres through talks, papers and personal contact; other interested bodies through meetings and layman's reports; schools and the wider public through articles and talks.
These data will also be used to develop a modified mechanism for low NOx oxidation of isoprene based on both the Master Chemical Mechanism and the Common Representative Intermediates methodologies. These mechanisms will also be available from the groups' websites but also from the main MCM website as well for anyone to use. The MCM (containing the CRI) website provides users with the opportunity to download the mechanism is a variety of different formats, suitable to the users needs. These modified mechanisms will be used in both a regional (trajectory model) and the global model CRI-STOCHEM. The models will be intergrated and compared with available field data to assesses the impact on OH recycling. The results from these integrations will also form the basis for a research paper.
We will attend UK (e.g. university departmental seminar series, Royal Society of Chemistry's Gas-Kinetics meetings, Royal Meteorological Societies Atmospheric Chemistry Group meetings and the R. Met. Soc. annual conference) and international meetings (e.g. EGU and AGU) to present this work in both oral presentations and poster form.
Between the two groups we have active collaborations with a number of UK research groups and Centres (e.g. NERC National Centre for Atmos. Sci., NERC Centre for Ecology and Hydrology) as well as many groups outside the UK. In the course of these collaborations we would give presentations on visits, discuss new data via e-mail etc. and receive feedback.
We already have regular contact with the U.K. Met. Office and DECC (Dept. Energy and Climate Change) through other on-going projects and will update them on progress of this work. Other groups we interact with include, the UK Home Office, DSTL (Porton Down), a range of instrument manufacturers and chemical suppliers and as a matter of course we update them about new work we are undertaking.
We will write a layman's summary of the outcomes of the project and this will be posted on our websites too. In addition we will develop about 3 pages that will be based on Bristol ChemLabS' very successful Dynamic Laboratory Manual. The dynamic web-pages will be directed at a general audience (suitable for average 10 year olds for the basic one and 14 year olds and then 16 year olds for the other two) and will cover the background to atmospheric pollution and climate change.
Through the help of the Bristol ChemLabS' School Teacher Fellow and Science Communicator in Residence, Tim Harrison, this project will give talks heavily populated with lively experiments, called a 'Pollutants' Tale' for secondary school and older (> 11 years old) and 'Gases in the air' for primary school (4-11 years old), at schools, UK science festivals and to general interest groups. We expect to engage with at least 15,000 people directly by the end of this three year project. We will also write at least one article for the journal Science in School, which is read by 130,000 schools, their teachers and students across Europe. Articles we have written on atmospheric chemistry in the past 3-4 years have been downloaded over 250,000 times. These papers have also led to us providing a book chapter of a work on the Earth's Climate.
Our strategy for impact covers; academics and research centres through talks, papers and personal contact; other interested bodies through meetings and layman's reports; schools and the wider public through articles and talks.
Organisations
Publications
Bannan T
(2015)
The first UK measurements of nitryl chloride using a chemical ionization mass spectrometer in central London in the summer of 2012, and an investigation of the role of Cl atom oxidation
in Journal of Geophysical Research: Atmospheres
Boxe C
(2012)
The effect of the novel HO 2 + NO ? HNO 3 reaction channel at South Pole, Antarctica
in Antarctic Science
Caravan RL
(2020)
Direct kinetic measurements and theoretical predictions of an isoprene-derived Criegee intermediate.
in Proceedings of the National Academy of Sciences of the United States of America
Chhantyal-Pun R
(2017)
Direct Measurements of Unimolecular and Bimolecular Reaction Kinetics of the Criegee Intermediate (CH3)2COO.
in The journal of physical chemistry. A
Chhantyal-Pun R
(2019)
Direct Kinetic and Atmospheric Modeling Studies of Criegee Intermediate Reactions with Acetone
in ACS Earth and Space Chemistry
Chhantyal-Pun R
(2018)
Criegee Intermediate Reactions with Carboxylic Acids: A Potential Source of Secondary Organic Aerosol in the Atmosphere
in ACS Earth and Space Chemistry
Chhantyal-Pun R
(2020)
Criegee intermediates: production, detection and reactivity
in International Reviews in Physical Chemistry
Chhantyal-Pun R
(2019)
Experimental and computational studies of Criegee intermediate reactions with NH3 and CH3NH2.
in Physical chemistry chemical physics : PCCP
Chhantyal-Pun R
(2017)
Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates.
in Angewandte Chemie (International ed. in English)
Chhantyal-Pun R
(2015)
A kinetic study of the CH2OO Criegee intermediate self-reaction, reaction with SO2 and unimolecular reaction using cavity ring-down spectroscopy.
in Physical chemistry chemical physics : PCCP
Chhantyal-Pun R
(2017)
Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates
in Angewandte Chemie
Chhantyal-Pun R
(2020)
Impact of Criegee Intermediate Reactions with Peroxy Radicals on Tropospheric Organic Aerosol
in ACS Earth and Space Chemistry
Copeland G
(2014)
Determination of the photolysis rate coefficient of monochlorodimethyl sulfide (MClDMS) in the atmosphere and its implications for the enhancement of SO2 production from the DMS + Cl2 reaction.
in Environmental science & technology
Derwent R
(2015)
Tropospheric ozone production regions and the intercontinental origins of surface ozone over Europe
in Atmospheric Environment
Derwent R
(2012)
Seasonal cycles in short-lived hydrocarbons in baseline air masses arriving at Mace Head, Ireland
in Atmospheric Environment
Ghalaieny M
(2012)
Determination of gas-phase ozonolysis rate coefficients of a number of sesquiterpenes at elevated temperatures using the relative rate method.
in Physical chemistry chemical physics : PCCP
Hamer P
(2014)
Investigating the photo-oxidative and heterogeneous chemical production of HCHO in the snowpack at the South Pole, Antarctica
in Environmental Chemistry
Harrison R
(2012)
Atmospheric chemistry and physics in the atmosphere of a developed megacity (London): an overview of the REPARTEE experiment and its conclusions
in Atmospheric Chemistry and Physics
Henne S
(2012)
Future emissions and atmospheric fate of HFC-1234yf from mobile air conditioners in Europe.
in Environmental science & technology
Higgins CM
(2014)
Quantum yields for photochemical production of NO2 from organic nitrates at tropospherically relevant wavelengths.
in The journal of physical chemistry. A
Holland R
(2021)
Investigation of the Production of Trifluoroacetic Acid from Two Halocarbons, HFC-134a and HFO-1234yf and Its Fates Using a Global Three-Dimensional Chemical Transport Model
in ACS Earth and Space Chemistry
Jones B
(2014)
Airborne measurements of HC(O)OH in the European Arctic: A winter - summer comparison
in Atmospheric Environment
Khan M
(2016)
A modelling study of the atmospheric chemistry of DMS using the global model, STOCHEM-CRI
in Atmospheric Environment
Khan M
(2020)
Investigating the Impacts of Nonacyl Peroxy Nitrates on the Global Composition of the Troposphere Using a 3-D Chemical Transport Model, STOCHEM-CRI
in ACS Earth and Space Chemistry
Khan M
(2021)
Investigation of Biofuel as a Potential Renewable Energy Source
in Atmosphere
Khan M
(2015)
Estimation of Daytime NO 3 Radical Levels in the UK Urban Atmosphere Using the Steady State Approximation Method
in Advances in Meteorology
Khan M
(2017)
A modeling study of secondary organic aerosol formation from sesquiterpenes using the STOCHEM global chemistry and transport model
in Journal of Geophysical Research: Atmospheres
Khan M
(2015)
Global modeling of the C1-C3 alkyl nitrates using STOCHEM-CRI
in Atmospheric Environment
Khan M
(2015)
Global analysis of peroxy radicals and peroxy radical-water complexation using the STOCHEM-CRI global chemistry and transport model
in Atmospheric Environment
Khan M
(2018)
Investigating the Tropospheric Chemistry of Acetic Acid Using the Global 3-D Chemistry Transport Model, STOCHEM-CRI
in Journal of Geophysical Research: Atmospheres
Khan M
(2015)
A study of global atmospheric budget and distribution of acetone using global atmospheric model STOCHEM-CRI
in Atmospheric Environment
Khan M
(2015)
The global budgets of organic hydroperoxides for present and pre-industrial scenarios
in Atmospheric Environment
Khan M
(2019)
Investigating the behaviour of the CRI-MECH gas-phase chemistry scheme on a regional scale for different seasons using the WRF-Chem model
in Atmospheric Research
Khan M
(2020)
Global and regional model simulations of atmospheric ammonia
in Atmospheric Research
Khan M
(2021)
Changes to simulated global atmospheric composition resulting from recent revisions to isoprene oxidation chemistry
in Atmospheric Environment
Khan M
(2015)
Global modeling of the nitrate radical (NO3) for present and pre-industrial scenarios
in Atmospheric Research
Khan M
(2014)
Reassessing the photochemical production of methanol from peroxy radical self and cross reactions using the STOCHEM-CRI global chemistry and transport model
in Atmospheric Environment
Khan MAH
(2018)
Criegee intermediates and their impacts on the troposphere.
in Environmental science. Processes & impacts
Khan MAH
(2021)
Investigating the background and local contribution of the oxidants in London and Bangkok.
in Faraday discussions
Le Breton M
(2012)
Airborne observations of formic acid using a chemical ionization mass spectrometer
in Atmospheric Measurement Techniques
Le Breton M
(2014)
Simultaneous airborne nitric acid and formic acid measurements using a chemical ionization mass spectrometer around the UK: Analysis of primary and secondary production pathways
in Atmospheric Environment
Le Breton M
(2013)
Airborne hydrogen cyanide measurements using a chemical ionisation mass spectrometer for the plume identification of biomass burning forest fires
in Atmospheric Chemistry and Physics
Leather K
(2012)
Acid-yield measurements of the gas-phase ozonolysis of ethene as a function of humidity using Chemical Ionisation Mass Spectrometry (CIMS)
in Atmospheric Chemistry and Physics
Leather KE
(2012)
Temperature and pressure dependence of the rate coefficient for the reaction between ClO and CH3O2 in the gas-phase.
in Physical chemistry chemical physics : PCCP
Lee EP
(2012)
Spectroscopy of the simplest Criegee intermediate CH2OO: simulation of the first bands in its electronic and photoelectron spectra.
in Chemistry (Weinheim an der Bergstrasse, Germany)
McGillen M
(2017)
Criegee Intermediate-Alcohol Reactions, A Potential Source of Functionalized Hydroperoxides in the Atmosphere
in ACS Earth and Space Chemistry
Muller J
(2012)
Energy and ozone fluxes over sea ice
in Atmospheric Environment
Percival CJ
(2013)
Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.
in Faraday discussions
Sewry J
(2014)
Offering Community Engagement Activities To Increase Chemistry Knowledge and Confidence for Teachers and Students
in Journal of Chemical Education
| Description | The oxidation of isoprene is very important and through laboratory and modelling studies we have shown that it has a global impact through enhancement of OH levels. Such enhancements reduce greenhouse lifetimes (e.g. CH4) |
| Exploitation Route | We are working with the MCM team at Leeds to make sure that our data are incorporated into the latest version of the mechanism so that it can be used by others in the community |
| Sectors | Education,Environment,Transport |
| Description | We have provided data for schools to use as examples of environmental data. We have supported schools projects with this work, e.g. walk to school projects |
| First Year Of Impact | 2014 |
| Sector | Education |
| Description | Leverhulme Grant Scheme |
| Amount | £186,000 (GBP) |
| Organisation | The Leverhulme Trust |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 02/2014 |
| End | 02/2017 |
| Description | Please look at http://www.chemlabs.bris.ac.uk/outreach/latest.html this details the myriad outreach work that we do |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Schools |
| Results and Impact | We run numerous Outreach activities please refer to the website log. Please read our education papers 1. Criegee Biradicals and Climate Change. D.E. Shallcross and T.G. Harrison. Education in Chemistry 50(5) 22-24, 2013 2. Creating Climate Change Awareness in South African Schools Through Practical Chemistry Demonstrations. Suthananda N Sunassee, Ryan M Young, Joyce D Sewry, Timothy G Harrison, Dudley E Shallcross. Acta Didactica Napocensia 4, 35-48 (2012). 3. Outreach within the Bristol ChemLabS CETL (Centre for Excellence in Teaching and Learning). D.E. Shallcross, T.G. Harrison, T.M. Obey, S.J. Croker, N.C. Norman. Higher Education Studies 3(1), 39-49, 2013 4. |
| Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010,2011,2012,2013,2014 |
| URL | http://www.chemlabs.bris.ac.uk/outreach/latest.html |