Overview

The dominant source of hydrocarbons to the atmosphere is vegetation – biogenic volatile organic compounds or BVOCs.  In the atmosphere, BVOCs undergo chemical processing, leading to the formation of secondary pollutants such as ozone and organic aerosol particles, affecting human and environmental health and climate.  Therefore, understanding total BVOC emissions, and their response to (for example) temperature or CO2 abundance is a key priority to predict future biogeochemical cycling.

While many BVOCs can be measured using established techniques, some species are more difficult to quantify – in particular monoterpenes (C10H16 species) and sesquiterpenes (C15H24­ species) which dominate biogenic emissions, and which react with ozone.  In parallel, measurements above forests suggest that existing data underestimates BVOC abundance.  To address this challenge, we have developed a new approach to quantifying BVOCs, by directly measuring their total ozone reactivity in the air – a new metric which determines the overall reactive pool of BVOCs present, and which may be compared with traditional measurements of individual species.  In this project, you will develop this new instrument, validate its performance in the laboratory, and deploy the instrument at the Birmingham Institute of Forest Research (BIFoR) facility to investigate BVOC emissions from a nature forest under enhanced CO2 conditions.  A key priority is to identify the temperature response of BVOC emissions.  Later stages of the project are likely to involve further field deployments, potentially including with collaborators in Australia (Western Sydney) and Japan (Tokyo).  The project builds upon a current NERC research grant which has supported the prototype instrument development, and will be carried out within a dynamic group of PhD students and postdocs addressing a range of atmospheric chemistry problems.

Mobile laboratory deployed at the BIFoR-FACE facility sampling BVOC reactivity in an enhanced-CO2 environment.  How will vegetation emissions change in future  ?

Methodology

Instrument development work will be carried out at Birmingham, including measurements of BVOC emissions from individual plant species as a function of temperature and ligh, using the existing total ozone reactivity instrument, alongside conventional analytical approaches such as gas chromatography-mass spectrometry (GCMS) and proton-transfer-reaction mass spectrometry (PTRMS), with instruments in our laboratory.  Field observations of total BVOC reactivity will be performed at the BIFoR-FACE Free Air Carbon Enrichment facility in Staffordshire, alongside deployment of the PTRMS and other atmospheric monitors.  We will interpret these data using an atmospheric box model to relate the observed reactivity to individual species emissions, as a function of temperature and sunlight, and use the results to derive parameterisations for use in global models (by other researches in the group).  Finally, we will look to perform experiments at the EucFACE facility at Western Syndney (in a comparable FACE facility studying eucalyptus trees), and Waseda Univeristy in Tokyo (with collaborators developing a similar apporach) to extend the range of environments studied.  The project will operate in parallel to and benefit from the resources and staff of several current NERC research grants looking at related aspects of ozone chemistry and air pollution.

 

Training and Skills

CENTA students are required to complete 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to the student's projects and themes. 

Full training in the measurement instrument, use of supporting analytical equipment and the modelling techniques involved will be provided, with day-to-day help and guidance available from other members of the research group (PhD students and post-docs).  The candidate may also attend modules from Atmospheric Science MSc courses at Birmingham. They will be trained in an interdisciplinary environment, and collaborate with colleagues whose interests span environmental chemistry, meteorology, climatology, atmospheric chemistry and air quality.  They will be encouraged to attend the NERC NCAS Atmospheric Science training course, and supported in preparing their results for publication in journals and at national / international conferences.

 

Timeline

Year 1: Training; trial measurements on the University campus; experiments with individual plant species at the University; detailed fieldwork planning.  Attend NCAS Atmospheric Field Measurements training course.

Year 2: Main field measurement period, covering the growing season at BIFoR, assessing BVOC reactivity in treatment (enhanced CO2) and control (ambient conditions) forest plots.  Presentation of results at UK / EU meetings.

Year 3: Data analysis and parameterisation; further field measurements in Australia and/or Japan.    Presentation of results at international meetings e.g. AGU, San Francisco.  Thesis preparation.

Partners and collaboration (including CASE)

This project is offered by the University of Birmingham in collaboration with staff from the Birmingham Institute of Forest Research (BIFoR), and groups from the National Centre for Atmospheric Science who are collaborating in related field measurement programmes.  In addition to the Birmingham group, it is envisaged that the successful student will be able to collaborate with groups in Western Sydney and Waseda Universities. 

 

Further Details

For informal discussion of the project please contact Professor William (Bill) Bloss (w.j.bloss@bham.ac.uk).