Gas phase studies of the kinetics of Criegee Intermediates
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
The Earth's atmosphere is a complex mixture of gases, liquids and even solids. This mainly gaseous envelope around us performs many vital functions e.g. it protects us from harmful ultraviolet light (high energy light) from the Sun through the stratospheric ozone layer. Through the water cycle, clouds are formed in the atmosphere that redistributes water in the Earth systems. These clouds also cool the planet by acting like mirrors, reflecting some of the energy from the Sun back to outer space. This cooling mechanism is essential to the Earth system to permit an equitable surface temperature to exist that allows all the diverse life forms on it to exist. As well as this natural cooling mechanism, so called greenhouse gases in the atmosphere (e.g. carbon dioxide, CO2 and methane CH4) absorb infrared energy released by the Earth and trap some of it, very similar to the analogy of putting on a blanket and warm the Earth's surface up. Both these natural cooling and warming mechanisms are essential to a habitable surface and as long as they stay in balance, the surface temperature will remain reasonably constant. However, over the last 200 years humans have been increasing the level of greenhouse gases in the atmosphere by burning fossil fuels and evidence shows that this is leading to an overall warming of the surface of the Earth. The consequences of even a modest increase in average global surface temperature are significant for human, animal and plant life.
It is known that chemicals released naturally by plants (unsaturated organic molecules such as alkenes) can react with oxidants in the atmosphere to produce extremely fast reacting intermediates, so called Criegee intermediates (CI). However, recent studies by us have shown that these Criegee intermediates react rapidly with a number of species present in the atmosphere such as sulphur dioxide (SO2). Ultimately, these reactions lead to the formation of sulphuric acid, which is very good at promoting aerosol formation (cloud precursors). Under polluted environments, aerosol formation may have detrimental effects on health but in the background atmosphere, promotion of cloud formation leads to a cooling of the Earth's surface. We have assessed the possible impact of these natural emissions of chemicals using computer models of the atmosphere and it appears that this process may be very important in producing cloud precursors and therefore be having an important impact on the Earth's climate (cooling it).
However, we have only been able to investigate the reactions of two possible Criegee intermediates and there are potentially thousands of different ones. Whilst it would be impossible to study them all and indeed not a sensible endeavour, it is important to study different types of Criegee intermediates. If they all have a similar reactivity then the impact on the atmosphere is likely to be true and would then be important to include in climate models. In order to investigate how quickly these Criegee intermediates react with species such as SO2 we have devised an experiment in the laboratory that takes advantage of recent developments in optics. Using laser light to generate these Criegee intermediates we will be able to detect them using a highly sensitive technique called cavity ringdown spectroscopy (CRDS). In the experiment the Criegee intermediate is generated in a closed system where light is trapped between two highly reflective mirrors. As the light bounces backwards and forwards between the mirrors it may be absorbed by the Criegee intermediate and so less light is left. The greater the level of Criegee intermediate made the less light is reflected back and forth and so we have a way to measure this species. In this way we will be able to investigate how fast these Criegee intermediates react with a number of important gases in the Earth's atmosphere.
It is known that chemicals released naturally by plants (unsaturated organic molecules such as alkenes) can react with oxidants in the atmosphere to produce extremely fast reacting intermediates, so called Criegee intermediates (CI). However, recent studies by us have shown that these Criegee intermediates react rapidly with a number of species present in the atmosphere such as sulphur dioxide (SO2). Ultimately, these reactions lead to the formation of sulphuric acid, which is very good at promoting aerosol formation (cloud precursors). Under polluted environments, aerosol formation may have detrimental effects on health but in the background atmosphere, promotion of cloud formation leads to a cooling of the Earth's surface. We have assessed the possible impact of these natural emissions of chemicals using computer models of the atmosphere and it appears that this process may be very important in producing cloud precursors and therefore be having an important impact on the Earth's climate (cooling it).
However, we have only been able to investigate the reactions of two possible Criegee intermediates and there are potentially thousands of different ones. Whilst it would be impossible to study them all and indeed not a sensible endeavour, it is important to study different types of Criegee intermediates. If they all have a similar reactivity then the impact on the atmosphere is likely to be true and would then be important to include in climate models. In order to investigate how quickly these Criegee intermediates react with species such as SO2 we have devised an experiment in the laboratory that takes advantage of recent developments in optics. Using laser light to generate these Criegee intermediates we will be able to detect them using a highly sensitive technique called cavity ringdown spectroscopy (CRDS). In the experiment the Criegee intermediate is generated in a closed system where light is trapped between two highly reflective mirrors. As the light bounces backwards and forwards between the mirrors it may be absorbed by the Criegee intermediate and so less light is left. The greater the level of Criegee intermediate made the less light is reflected back and forth and so we have a way to measure this species. In this way we will be able to investigate how fast these Criegee intermediates react with a number of important gases in the Earth's atmosphere.
Planned Impact
Beyond academic beneficiaries identified myriad other groups will benefit from this research. First, this work addresses the issue of air quality through proposing new routes to aerosol formation via Criegee biradical mediated oxidation of SO2. Since a major source of alkenes in the urban environment is from natural systems such as trees and these are precursors to Criegee biradical formation, groups such as urban planners, forestry commissions, environment agencies, air quality management groups and ultimately groups such as Defra in the UK will want to understand the implications of this research. Outside the UK, Environment agencies in other countries will also want to assess the impact of this research on their urban air quality strategies. Hence these data should impact on policy makers.
Second, these data will potentially impact on the indoor environment and may alter our perception about what are poor combinations of chemicals in these environments with respect to secondary aerosol formation. Architects and building specialists will want to understand how these new data affect the impact of emissions from a variety of materials on indoor aerosol and how ventilation schemes and outdoor pollutant levels will combine with indoor emissions to generate aerosol. A variety of indoor environments may potentially be candidates for inspection where high volatile organic loadings and SO2 and O3 are collocated. These environments extend beyond buildings inhabited by humans and will include animal pens and a range of botanic settings. Therefore, a wide range of stakeholders could potentially be interested by these data and indoor habitats be impacted by them.
Third, based on preliminary model analysis, it appears that the reactions of Criegee biradicals with SO2 could be a very important additional oxidation pathway to form SO3 and ultimately sulphuric acid in the atmosphere. The implications of these data could be significant to our understanding of past, present and future climates. Although much further testing is required, ultimately groups such as the Met. Office in the UK will want to assess these impacts in detailed climate models. If the impact persists on detailed inspection then this will factor in our understanding of past climates as well as current and future ones. In all this work may eventually point to an even more important role for terrestrial and aquatic ecosystems in off-setting climate change and this will be of considerable benefit to groups such as IPCC as they continue to refine their assessments about the direction and speed of climate change.
Therefore, we believe that the primary impact will be on our understanding of the atmosphere and that this may affect future air quality and climate policies.
In the Education sector, where we place considerable emphasis, studies of this kind provide considerable stimulus for future young scientists and provide teachers with new material to broaden curricula. We have set out ways we hope to support the dissemination of these studies to this group in a direct and effective manner.
Economic benefits can be envisaged, e.g. through analytical scientists, new detection techniques may emerge for biradical species and these may lead to new instruments with potential economic benefits. If these data do highlight important 'new' processes taking place in the atmosphere then there may be subsequent economic benefits from policies that preserve good air quality and address (even in a modest way) the issue of climate change on regional, national and even global scales.
Second, these data will potentially impact on the indoor environment and may alter our perception about what are poor combinations of chemicals in these environments with respect to secondary aerosol formation. Architects and building specialists will want to understand how these new data affect the impact of emissions from a variety of materials on indoor aerosol and how ventilation schemes and outdoor pollutant levels will combine with indoor emissions to generate aerosol. A variety of indoor environments may potentially be candidates for inspection where high volatile organic loadings and SO2 and O3 are collocated. These environments extend beyond buildings inhabited by humans and will include animal pens and a range of botanic settings. Therefore, a wide range of stakeholders could potentially be interested by these data and indoor habitats be impacted by them.
Third, based on preliminary model analysis, it appears that the reactions of Criegee biradicals with SO2 could be a very important additional oxidation pathway to form SO3 and ultimately sulphuric acid in the atmosphere. The implications of these data could be significant to our understanding of past, present and future climates. Although much further testing is required, ultimately groups such as the Met. Office in the UK will want to assess these impacts in detailed climate models. If the impact persists on detailed inspection then this will factor in our understanding of past climates as well as current and future ones. In all this work may eventually point to an even more important role for terrestrial and aquatic ecosystems in off-setting climate change and this will be of considerable benefit to groups such as IPCC as they continue to refine their assessments about the direction and speed of climate change.
Therefore, we believe that the primary impact will be on our understanding of the atmosphere and that this may affect future air quality and climate policies.
In the Education sector, where we place considerable emphasis, studies of this kind provide considerable stimulus for future young scientists and provide teachers with new material to broaden curricula. We have set out ways we hope to support the dissemination of these studies to this group in a direct and effective manner.
Economic benefits can be envisaged, e.g. through analytical scientists, new detection techniques may emerge for biradical species and these may lead to new instruments with potential economic benefits. If these data do highlight important 'new' processes taking place in the atmosphere then there may be subsequent economic benefits from policies that preserve good air quality and address (even in a modest way) the issue of climate change on regional, national and even global scales.
Organisations
Publications
McGillen M
(2017)
Criegee Intermediate-Alcohol Reactions, A Potential Source of Functionalized Hydroperoxides in the Atmosphere
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
(2019)
Direct Kinetic and Atmospheric Modeling Studies of Criegee Intermediate Reactions with Acetone
in ACS Earth and Space Chemistry
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
Chhantyal-Pun R
(2020)
Impact of Criegee Intermediate Reactions with Peroxy Radicals on Tropospheric Organic Aerosol
in ACS Earth and Space Chemistry
Khan M
(2021)
Impacts of Hydroperoxymethyl Thioformate on the Global Marine Sulfur Budget
in ACS Earth and Space Chemistry
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
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
Chhantyal-Pun R
(2017)
Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates
in Angewandte Chemie
Welz O
(2014)
Rate coefficients of C(1) and C(2) Criegee intermediate reactions with formic and acetic Acid near the collision limit: direct kinetics measurements and atmospheric implications.
in Angewandte Chemie (International ed. in English)
Chhantyal-Pun R
(2017)
Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates.
in Angewandte Chemie (International ed. in English)
Khan M
(2021)
Investigation of Biofuel as a Potential Renewable Energy Source
in Atmosphere
Holland R
(2020)
Investigating the Atmospheric Sources and Sinks of Perfluorooctanoic Acid Using a Global Chemistry Transport Model
in Atmosphere
Diaz F
(2020)
Ozone Trends in the United Kingdom over the Last 30 Years
in Atmosphere
Foulds A
(2021)
Abundance of NO3 Derived Organo-Nitrates and Their Importance in the Atmosphere
in Atmosphere
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
Khan M
(2016)
A modelling study of the atmospheric chemistry of DMS using the global model, STOCHEM-CRI
in Atmospheric Environment
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
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
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)
Global analysis of peroxy radicals and peroxy radical-water complexation using the STOCHEM-CRI global chemistry and transport model
in Atmospheric Environment
Khan M
(2015)
Global modeling of the C1-C3 alkyl nitrates using STOCHEM-CRI
in Atmospheric Environment
Derwent R
(2021)
Intercomparison of the representations of the atmospheric chemistry of pre-industrial methane and ozone in earth system and other global chemistry-transport models
in Atmospheric Environment
Derwent R
(2015)
Tropospheric ozone production regions and the intercontinental origins of surface ozone over Europe
in Atmospheric Environment
Jones B
(2014)
Airborne measurements of HC(O)OH in the European Arctic: A winter - summer comparison
in Atmospheric Environment
Khan M
(2021)
Changes to simulated global atmospheric composition resulting from recent revisions to isoprene oxidation chemistry
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
(2015)
Global modeling of the nitrate radical (NO3) for present and pre-industrial scenarios
in Atmospheric Research
Khan M
(2020)
Global and regional model simulations of atmospheric ammonia
in Atmospheric Research
White I
(2014)
A feasibility study of the use of reactive tracers to determine outdoor daytime OH radical concentrations within the urban environment
in Atmospheric Science Letters
Hamer P
(2014)
Investigating the photo-oxidative and heterogeneous chemical production of HCHO in the snowpack at the South Pole, Antarctica
in Environmental Chemistry
Taatjes CA
(2019)
Reaction of Perfluorooctanoic Acid with Criegee Intermediates and Implications for the Atmospheric Fate of Perfluorocarboxylic Acids.
in Environmental science & technology
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
Khan MAH
(2018)
Criegee intermediates and their impacts on the troposphere.
in Environmental science. Processes & impacts
Percival CJ
(2013)
Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.
in Faraday discussions
Weber J
(2021)
Improvements to the representation of BVOC chemistry-climate interactions in UKCA (v11.5) with the CRI-Strat 2 mechanism: incorporation and evaluation
in Geoscientific Model Development
Shallcross DE
(2014)
Criegee intermediates in the indoor environment: new insights.
in Indoor air
Chhantyal-Pun R
(2020)
Criegee intermediates: production, detection and reactivity
in International Reviews in Physical Chemistry
Sewry J
(2014)
Offering Community Engagement Activities To Increase Chemistry Knowledge and Confidence for Teachers and Students
in Journal of Chemical Education
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
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
Bannan T
(2017)
Ground and Airborne U.K. Measurements of Nitryl Chloride: An Investigation of the Role of Cl Atom Oxidation at Weybourne Atmospheric Observatory
in Journal of Geophysical Research: Atmospheres
Wright M
(2014)
Indoor and outdoor atmospheric ion mobility spectra, diurnal variation, and relationship with meteorological parameters Indoor/outdoor air ion mobility spectra
in Journal of Geophysical Research: Atmospheres
Bannan T
(2017)
Seasonality of Formic Acid (HCOOH) in London during the ClearfLo Campaign
in Journal of Geophysical Research: Atmospheres
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
Taatjes CA
(2014)
Atmospheric chemistry: intermediates just want to react.
in Nature chemistry
Caravan RL
(2018)
The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol.
in Nature communications
Description | Many public presentations and invites to give plenary talks at prestigious conferences. The data are currently being analysed in detail but suggest that CI species could be reducung the impact of pollution by accelerating their removal. Work has been published and presented and is being compiled to generate SARs for model purposes. |
Sector | Education,Environment,Transport |
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 |