MOCHA

Introduction

Molecular Characterisation of Anthropogenic Secondary Organic Aerosols (MOCHA)

MOCHA is a 2 year MCSA European project awarded to Dr. Elena Gomez Alvarez. It will be carried out at University of Cork (UCC) with secondments at the University of Cambridge, UK. This research project aims at the characterisation of key chemical species and processes leading to anthropogenic secondary organic aerosol (SOA) formation in particular of organic aerosols in ambient urban air. On a global basis, biomass burning is one of the main contributors of organic aerosols (both primary and secondary) and light absorbing brown and black carbon.

Project Information

MOCHA is a Marie Curie Fellowship awarded to Dr. Elena Gomez Alvarez by the European Commission.

Title: Molecular Characterisation of Anthropogenic Secondary Organic Aerosols (MOCHA).
Fellow: Dr. Elena Gomez Alvarez
Host Scientist: Prof. John Wenger (UCC)
Secondments: Prof. Markus Karlberer (University of Cambridge)
Grant No: 751527-MOCHA-H2020-MSCA-IF-2016
Start Date:
01 September, 2017
Completion Date: 31 August, 2019
Amount of Award: €187,866
Activities: Statistical and graphical data analysis methods, data mining, training in operation of state-of-the-art aerosol instrumentation, field measurements, simulation chamber runs, personal development, dissemination and outreach.

The Fellow

Dr. Elena Gomez Alvarez

Project Description

The scientific objectives of this project are: 

1. To characterise the molecular composition of organic aerosols in ambient urban air. 
2. To use molecular markers for identifying and estimating the relative importance of the various sources (primary and secondary, natural and anthropogenic) of organic aerosols. 
3. To characterise the molecular composition of SOA generated from a range of anthropogenic precursors under a variety of reaction conditions in an atmospheric simulation chamber. 
4. To identify the key chemical species and processes leading to anthropogenic SOA formation. 

The project will involve field campaigns and laboratory studies carried out in the new atmospheric simulation chamber currently under construction at the Centre for Research In Atmospheric Chemistry (CRAC), School of Chemistry at UCC.

A key element of this research will be to use state-of-the-art analytical instrumentation for the characterisation of organic aerosols:

- Online analysis using a Time-of-Flight Chemical Ionisation Mass Spectrometer (TOF-CIMS) coupled with a Filter Inlet for Gases and Aerosols (FIGAERO) at University College Cork, Ireland.

- Detailed offline analysis using Ultra-high resolution mass spectrometry (Orbitrap) at University of Cambridge, UK.

A range of data analysis procedures will be used to interpret the complex datasets collected using these instruments. The unique information obtained from this combined field and laboratory study will be used to improve our understanding of the composition, sources and processes leading to organic aerosol formation in the atmosphere, and in turn, the impact of SOA on human health and climate.

Scientific Background

Over the last 10-15 years, clear progress has been made in identifying many of the biogenic and anthropogenic VOCs involved in SOA production, as well as some of the mechanisms for SOA formation and growth. However, improved knowledge of the molecular composition of SOA is urgently needed to advance our understanding of; (i) relevant climate and health-related properties of particles, e.g. hygroscopicity and prevalence of toxic compounds, and (ii) the various sources and processes involved in formation of atmospheric particles. 

It is essential while remaining a challenge, to determine the sources of primary and secondary aerosols produced from biomass burning. The evaluation of their impact on regional and local air quality require to improve our capacity to characterise them on a molecular basis. “Source apportionment” approaches constitute a valuable resource, which consists of the identification and quantification of specific molecular markers.

The limitations of the conventional chromatographic methods have recently been overcome by the use of UHRMS, which, due to its higher mass resolving power, has enabled identification of many hundreds of different species in a single analytical step, with efforts mainly focussed on Biogenic SOA formation from plant emissions such as isoprene and the monoterpenes. This analytical breakthrough, has helped to revolutionize the molecular characterisation of organic aerosols and within the last few years, UHRMS has been successfully applied in several laboratory and field studies.

However, interpretation of these field measurements is hindered by the lack of available chamber generated data on the molecular composition of SOA from anthropogenic precursors such as alkanes, alkenes, aromatics, polycyclic aromatic hydrocarbons (PAHs). Clearly, more work is needed in this area. The aim of this project is to advance on the molecular characterisation of this anthropogenic SOA.

Useful Literature

  • Nizkorodov, S.A. et al.: Molecular chemistry of organic aerosols using high resolution mass spectrometry, Chem. Chem. Phys., 13, 3612, 2011. DOI

  • Kourtchev, I., Fuller, S., Aalto, J., Ruuskanen, T.M., McLeod, M.W., Maenhaut, W., Jones, R., Kulmala, M., Kalberer, M., 2013. Molecular composition of boreal forest aerosol from Hyytiälä, Finland, using ultrahigh resolution mass spectrometry. Environmental Science and Technology 47, 4069-4079. DOI

  • Kourtchev, I., et al.: Effects of anthropogenic emissions on molecular composition of urban organic aerosols: A UHRMS study, Env., 89, 525, 2014. DOI

  • Kourtchev, I. et al.: Molecular composition of biogenic SOA using UHRMS: comparing laboratory and field studies. Chem. Phys., 14, 2155, 2014. DOI

  • Kourtchev, I. et al.: Molecular composition of fresh and aged SOA from a mixture of biogenic volatile compounds. Chem. Phys., 15, 5683, 2015. DOI

  • Rincón, A.G. et al.: Seasonal differences of urban organic aerosol composition – a UHRMS study. Environ. Chem. 9, 298, 2012. DOI

  • Tong, H. et al.: Molecular composition of organic aerosols at urban background and road tunnel sites using UHRMS. Faraday Discuss., 189, 51, 2016. DOI

  • Lopez-Hilfiker, F.D. et al.: A novel method for online analysis of gas and particle composition: FIGAERO. Atmos. Meas. Tech., 7, 983 , 2014. DOI

  • Lopez-Hilfiker, F.D. et al.: Phase Partitioning and Volatility of Secondary Organic Aerosol Components. Atmos. Chem. Phys., 15, 7765, 2015. DOI

  • Lopez-Hilfiker, F.D. et al.: Molecular Composition and Volatility of Organic Aerosol in the Southeastern U.S. Environ. Sci. Technol.,50, 2200, 2016. DOI

  • Ben H.L. et al.: Highly functionalized organic nitrates in the southeast United States. Proc. Natl. Acad. Sci., 113, 1516, 2016. DOI

  • Gaston, C.J. et al.: Online molecular characterization of fine particulate matter in Port Angeles, WA. Atmos. Environ., 138, 99, 2016. DOI

  • Aljawhary, D. et al.: High-resolution ToF-CIMS: application to study SOA composition and processing., Atmos. Meas. Tech., 6, 3211, 2013. DOI

Collaborators

Dr. Ivan Kourtchev
Prof. Markus Karlberer (University of Cambridge, UK)

Presentations

Content to follow when available.

Publications

Content to follow when available.

Publicity and Outreach

Content to follow when available.

Contact Details

Dr. Elena Gomez Alvarez

Centre for Research into Atmospheric Chemistry

Lab B1, Kane Building, University College Cork, College Rd, Cork, Ireland

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