Improved Representation of Atmospheric Aerosol Hygroscopicity
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
Aerosols and clouds are important components of the Earth's atmosphere, influencing the radiation budget and chemical composition, and affecting human health. The impact of aerosols and clouds on global climate remains one of the largest single uncertainties in understanding previous climate observations and in predicting future climate change.
Aerosols and clouds can scatter and absorb sunlight and terrestrial radiation, having a direct effect on climate by altering the balance of incoming solar radiation and outgoing infrared light. Aerosols also have an indirect effect on climate by influencing the albedo and lifetime of clouds, because cloud droplets form from the much smaller aerosol particle seeds on which water can condense. Changes in the number of aerosol particles in the Earth's atmosphere and their size distribution can lead to changes in the number of cloud droplets that form. This indirect effect is poorly constrained and generally counteracts the warming induced by increased levels of greenhouse gases in the atmosphere, exerting a cooling effect on the Earth's climate.
The project "Reducing the Uncertainties in Aerosol Hygroscopic Growth", to which this project is linked, seeks to quantify the microphysical properties and processes that control the formation of cloud droplets from aerosol particles in a series of laboratory measurements on single, suspended, aerosol particles using state of the art techniques. These properties can then be used, in a much simplified form, in the computer models used to simulate atmospheric air quality and climate. One of these simplified methods is the "kappa-Köhler theory" created by our international partner (in the USA) on this project. Together, we will do the following:
First, we will exchange staff between the Bristol Aerosol Research Centre and the laboratory of our international partner at North Carolina State University for a short period (one focus area will be the viscosity of aerosol components). This will enable an exchange of skills: our work is mostly fundamental, and laboratory-based, whereas our international partner participates extensively in field campaigns of atmospheric measurements. These areas of interest, and associated science, are complementary.
Second we will work together to provide a database of values of the aerosol parameter kappa, and web-based tools to carry out calculations that are related to the uptake of water by atmospheric aerosols and their role in the formation of clouds. These tools will be publicly accessible on the Extended Aerosol Inorganics Model website. They should provide a focus for international efforts in this area, and help to spread best practice.
Third, will hold a Workshop, hosted with our international partner and with invited experts in the measurement and use of kappa and kappa-Köhler theory, to discuss current problems in the field and to recommend where future effort should be directed. One problem area is the kappa values of the organic components of atmospheric aerosols, whose behaviour and composition are both very complex, making it difficult to relate parameter kappa to composition in a direct or reliable way. The participants will also review the website tools and database, and make recommendations for future development.
In addition to the scientific benefits, UK participation and leadership in international atmospheric aerosol research will be advanced by the partnership and links created in this project.
Aerosols and clouds can scatter and absorb sunlight and terrestrial radiation, having a direct effect on climate by altering the balance of incoming solar radiation and outgoing infrared light. Aerosols also have an indirect effect on climate by influencing the albedo and lifetime of clouds, because cloud droplets form from the much smaller aerosol particle seeds on which water can condense. Changes in the number of aerosol particles in the Earth's atmosphere and their size distribution can lead to changes in the number of cloud droplets that form. This indirect effect is poorly constrained and generally counteracts the warming induced by increased levels of greenhouse gases in the atmosphere, exerting a cooling effect on the Earth's climate.
The project "Reducing the Uncertainties in Aerosol Hygroscopic Growth", to which this project is linked, seeks to quantify the microphysical properties and processes that control the formation of cloud droplets from aerosol particles in a series of laboratory measurements on single, suspended, aerosol particles using state of the art techniques. These properties can then be used, in a much simplified form, in the computer models used to simulate atmospheric air quality and climate. One of these simplified methods is the "kappa-Köhler theory" created by our international partner (in the USA) on this project. Together, we will do the following:
First, we will exchange staff between the Bristol Aerosol Research Centre and the laboratory of our international partner at North Carolina State University for a short period (one focus area will be the viscosity of aerosol components). This will enable an exchange of skills: our work is mostly fundamental, and laboratory-based, whereas our international partner participates extensively in field campaigns of atmospheric measurements. These areas of interest, and associated science, are complementary.
Second we will work together to provide a database of values of the aerosol parameter kappa, and web-based tools to carry out calculations that are related to the uptake of water by atmospheric aerosols and their role in the formation of clouds. These tools will be publicly accessible on the Extended Aerosol Inorganics Model website. They should provide a focus for international efforts in this area, and help to spread best practice.
Third, will hold a Workshop, hosted with our international partner and with invited experts in the measurement and use of kappa and kappa-Köhler theory, to discuss current problems in the field and to recommend where future effort should be directed. One problem area is the kappa values of the organic components of atmospheric aerosols, whose behaviour and composition are both very complex, making it difficult to relate parameter kappa to composition in a direct or reliable way. The participants will also review the website tools and database, and make recommendations for future development.
In addition to the scientific benefits, UK participation and leadership in international atmospheric aerosol research will be advanced by the partnership and links created in this project.
Planned Impact
This research, both in its immediate results and long term influence, will improve atmospheric models of air quality and climate by improving the representation of aerosol size (and consequent optical and visibility effects), and on cloud forming behaviour (cloud condensation nucleus activity). The short term beneficiaries are therefore atmospheric modellers, internationally, followed by the agencies and regulatory authorities who will make use of a more accurate understanding and predictions of the behaviour of the atmosphere and its response to human influence. This in turn will benefit human health and well-being.
The project will improve UK capability in the area of atmospheric aerosol science (both the underlying physical chemistry, and effects in the environment), by fostering links with leading international and especially U.S. researchers in all three planned activities: (i) exchange of staff between the two laboratories, (ii) creation of on-line database and tools, and (iii) the kappa-Kohler Theory Workshop.
The project will improve UK capability in the area of atmospheric aerosol science (both the underlying physical chemistry, and effects in the environment), by fostering links with leading international and especially U.S. researchers in all three planned activities: (i) exchange of staff between the two laboratories, (ii) creation of on-line database and tools, and (iii) the kappa-Kohler Theory Workshop.
People |
ORCID iD |
Jonathan Reid (Principal Investigator) | |
Simon Clegg (Co-Investigator) |
Publications
Rovelli G
(2016)
Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity.
in The journal of physical chemistry. A
Marsh A
(2018)
Amorphous phase state diagrams and viscosity of ternary aqueous organic/organic and inorganic/organic mixtures.
in Physical chemistry chemical physics : PCCP
Cai C
(2016)
Comparison of Methods for Predicting the Compositional Dependence of the Density and Refractive Index of Organic-Aqueous Aerosols.
in The journal of physical chemistry. A
Marsh A
(2019)
Complexity of Measuring and Representing the Hygroscopicity of Mixed Component Aerosol.
in The journal of physical chemistry. A
Rothfuss N
(2018)
Condensation Kinetics of Water on Amorphous Aerosol Particles
in The Journal of Physical Chemistry Letters
Rovelli G
(2017)
Hygroscopic properties of aminium sulfate aerosols
in Atmospheric Chemistry and Physics
Rovelli G
(2016)
Hygroscopic Properties of Aminium Sulphate Aerosols
Marsh A
(2017)
Influence of organic compound functionality on aerosol hygroscopicity: dicarboxylic acids, alkyl-substituents, sugars and amino acids
in Atmospheric Chemistry and Physics
Description | As proposed, we have held a workshop to assess our understanding of the hygroscopic growth of atmospheric aerosol, bringing together a ~17 academics from the US, Canada and Europe at a workshop held at North Carolina State University, US. We are in the process of drafting a white paper to summarise our conclusions which we expect to be an invaluable contribution to establish future needs for research in this area. |
Exploitation Route | White paper will be a critical source of the current state of the science, establishing priorities for future research. |
Sectors | Environment |
Title | Accurate Measurements of Aerosol Hygroscopic Growth Over a Wide Range in Relative Humidity |
Description | The hygroscopic properties of aerosol govern the response of aerosol particle size and composition to the relative humidity of the gas phase. The data sets in this project are accumulated from single particle measurements of hygroscopic response made at the Bristol Aerosol Research Centre. Here, we include data for the publication: Journal of Physical Chemistry A (2016) Accurate Measurements of Aerosol Hygroscopic Growth Over a Wide Range in Relative Humidity Grazia Rovelli [1,2], Rachael E.H. Miles [1], Jonathan P. Reid [1],* and Simon L. Clegg [3] 1 School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK 2 Department of Earth and Environmental Sciences, University of Milano-Bicocca, 20124 Milan, Italy 3 School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK Corresponding author: J. P. Reid (j.p.reid@bristol.ac.uk) |
Type Of Material | Database/Collection of data |
Year Produced | 2016 |
Provided To Others? | Yes |
Description | Collaboration with Prof. Markus Petters, North Carolina State University |
Organisation | North Carolina State University |
Department | Marine, Earth and Atmospheric Science |
Country | United States |
Sector | Academic/University |
PI Contribution | Research visits by students each direction, one to NCSU from Bristol and one from Bristol to NCSU. During extended visits of 3 weeks each, the students undertook collaborative measurements and these will lead to two publications (currently in preparation) |
Collaborator Contribution | Research visits by students each direction, one to NCSU from Bristol and one from Bristol to NCSU. During extended visits of 3 weeks each, the students undertook collaborative measurements and these will lead to two publications (currently in preparation) |
Impact | Publications in preparation |
Start Year | 2016 |
Description | Talk at Inhalation and Respiratory Drug Delivery Congress |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | Talk at the Inhalation and Respiratory Drug Delivery Congress in London |
Year(s) Of Engagement Activity | 2017 |
Description | Talk to local interest group |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Talk about atmospheric science and climate change at public engagement event held by A Rocha UK at Little Dewchurch, Herefordshire |
Year(s) Of Engagement Activity | 2017 |
Description | Workshop on aerosol hygroscopicity |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Workshop on aerosol hygroscopicity hosted at North Carolina State University in collaboration with Prof. Markus Petters and Prof. Simon Clegg. This will lead to a publication on atmospheric aerosol hygroscopicity. |
Year(s) Of Engagement Activity | 2017 |