Personal

I am Professor of Atmospheric Chemistry at Lancaster University and a Royal Society Wolfson Research Merit Award holder. I am a Fellow of the Royal Society of Chemistry.

RESEARCH

EMISSIONS OF BIOGENIC REACTIVE TRACE GASES AND THEIR ROLES IN THE EARTH SYSTEM

The biosphere is by far the largest source of reactive trace gases to the Earth’s atmosphere. They provide protection against abiotic and biotic stresses and allow plant-to-plant and plant-to-insect communication. Some of these compounds are highly reactive in the gas phase, and some are emitted in enormous, but unknown, quantities. The combination of high reactivity and large mass emission rates means these compounds play major roles in the physics and chemistry of the atmosphere. They mediate in the formation of ozone, hydroxyl and other oxidants, so controlling the oxidizing capacity of the atmosphere, which in turn controls the lifetime of methane and other radiatively-active “greenhouse” gases. They also form secondary organic aerosol (SOA) particles, which can directly influence the radiative balance of the atmosphere. SOA may activate cloud condensation nuclei (CNN), and by modifying cloud formation and properties can have indirect effects on climate. As well as their effects on radiative forcing, both ozone and aerosol particles have detrimental effects on human health and ecosystem functioning, and hence bVOCs play a role not only in the Earth’s climate system but also in air quality.

My research on bVOCs spans scales from the cell to the globe and includes both experimental and modelling work. Recently I was PI of a large NERC consortium studying the role of bVOCs in atmospheric composition and chemistry above a tropical rain forest in Malaysia (the “OP3” project – see OP3 special issue in ACP and other papers, including our 2009 paper in PNAS) and I now am preparing for a new project measuring isoprene fluxes in Amazonia.

NERC’s BAe 146 Facility for Airborne Atmospheric Measurements (FAAM) passing the Bukit Atur Global Atmosphere Watch station in Danum Valley, Malaysia during the OP3 project in 2008 (photo: Martin Irwin).

Ground level ozone concentrations estimated using a box model of atmospheric chemistry for the rainforest and oil palm landscapes in Malaysia (see Hewitt et al., 2009, PNAS for details.

CLIMATE-SOCIETY FEEDBACKS AND THE AVOIDANCE OF CLIMATE CHANGE

I have become very interested in how both individual actions and societal choices might influence atmospheric composition and hence climate. Having discovered the work of William Jevons and his paradox (his 1865 book “The Coal Question” is available on the web) I have recently begun collaborating with Andy Jarvis at Lancaster on climate–society feedbacks and the avoidance of climate change. We show that effective climate mitigation will require establishing a meaningful climate-society feedback to arrest the growth in global CO2 emissions through decarbonising global primary energy sources. I have also recently attempted to quantify the influence of realistic dietary choices on greenhouse gas emissions.

Teaching

ENV231. INTRODUCTION TO ATMOSPHERIC CHEMISTRY

ENV332. AIR QUALITY AND CLIMATE

ENV457. AIR QUALITY AND CLIMATE (4th year module)

Meetings recently organised

Chair and convener, Workshop “Forest fluxes and climate change”, Kuala Lumpur, 2007

Co-chair and co-convener, Royal Society Discussion meeting on “The biogeochemistry of trace gases and their role in climate change”, London, 2006

Co-convener and chair, Workshop, “BVOC emissions models and their applications”, Lancaster, 2011

Recent publications (since 2008) (please contact me for PFDs or for a full publication list)

The influence of small-scale variations in isoprene concentrations on atmospheric chemistry over a tropical rainforest (2011) T.A.M. Pugh, A.R. MacKenzie, B. Langford, P.K. Misztal and C.N. Hewitt, Atmospheric Chemistry and Physics 11, 4121-4134

Isoprene emissions from plants are mediated by atmospheric CO2 concentrations (2011) M. Possell and C.N. Hewitt, Global Change Biology, 17, 1595 – 1610

Direct ecosystem fluxes of volatile organic compounds from oil palms in South-East Asia (2011) P. K. Misztal, E. Nemitz, B. Langford, C. F. Di Marco, G. J. Phillips, C. N. Hewitt, A. R. MacKenzie, S. M. Owen, D. Fowler, M. R. Heal, and J. N. Cape, Atmospheric Chemistry and Physics Discussions, 11, 12671-12724

Evidence for a significant proportion of secondary organic aerosol from isoprene above a maritime tropical forest (2011) N. H. Robinson, J. F. Hamilton, J. D. Allan, B. Langford, D. E. Oram, Q. Chen, K. Docherty, D. K. Farmer, J. L. Jimenez, M. W. Ward, C. N. Hewitt, M. H. Barley, M. E. Jenkin, A. R. Rickard, S. T. Martin, G. McFiggans, and H. Coe, Atmospheric Chemistry and Physics, 11, 1039 – 1051

Quantification of VOC emission rates from the biosphere (2011) C.N. Hewitt, T. Karl, B. Langford, S.M. Owen and M. Possell, Trends in Analytical Chemistry, doi 10.1016/j.trac.2011.03.008

The impact of local surface processes in Borneo on atmospheric composition at wider spatial scales: coastal processes, land use change and air quality (2011) J. A. Pyle, N. J. Warwick, N. R. P. Harris, A. Archibald, M. J. Ashfold, K. Ashworth, M. P. Barkley, G. D. Carver, K. Chance, J. Dorsey, D. Fowler, S. Gonzi, B. Gostlow, C.N. Hewitt, T. P. Kurosu, J. D. Lee, B. Langford, G. Mills, S. Moller, A.R. MacKenzie, A. J. Manning, P. Misztal, Mohd Shahrul Mohd Nadzir, E. Nemitz, H. Newton, L. M. O’Brien, S. Ong, D. Oram, P. I. Palmer, Leong Kok Peng, Siew Moi Phang, R. Pike, T. Pugh, A. D. Robinson, Azizan Abu Samah, U. Skiba, Huan Eng Ung, Sei Eng Yong, P. Young, Philosophical Transactions of the Royal Society of London (in press)

Effects of land use on trace gas emissions and deposition in Borneo: comparing atmosphere-surface exchange over oil palm plantations with a rainforest (2011) D. Fowler, E. Nemitz, P. Misztal, C. Di Marco, U. Skiba, J. Ryder, C. Helfter, J.N Cape, S.M. Owen, M. Coyle, G. Phillips, B. Davison, B. Langford, A.R. MacKenzie, J. Muller, J. Siong, J. A. Pyle and C.N. Hewitt, Philosophical Transactions of the Royal Society of London (in press)

The atmospheric chemistry of trace gases and particulate matter emitted by different land uses in Borneo (2011) A. R. MacKenzie, B. Langford, T.A.M. Pugh, N. Robinson, P. K. Misztal, D. E. Heard, J. D. Lee, A. C. Lewis, C. E. Jones, J. R. Hopkins, G. Philips, P. S. Monks, A. Karunaharan, K. E. Hornsby, V. Nicolas-Perea, H. Coe, L.K. Whalley, P. M. Edwards, M. J. Evans, D. Stone, T. Ingham, R. Commane, K. L. Furneaux, J. McQuaid, E. Nemitz, Yap Kok Seng, D. Fowler, J. A. Pyle, and C.N. Hewitt, Philosophical Transactions of the Royal Society of London (in press)

Isoprene synthesis in plants: lessons from a transgenic tobacco model (2011) C. Vickers, M. Possell, J. Laothawornkitkul, A. Ryan, C.N. Hewitt and P. Mullineaux, Plant Cell and Environment DOI: 10.1111/j.1365-3040.2011.02303.x

Modelling chemistry in the nocturnal boundary layer above tropical rainforest and a generalised effective nocturnal deposition velocity for sub-ppbv NOx conditions (2011) T.A.M. Pugh, J. Ryder, A.R. MacKenzie, S.J. Moller, J.D. Lee and C.N. Hewitt, Journal of Atmospheric Chemistry doi:10.1007/s10874-011-9183-4

Effects of fosmidomycin on plant photosynthesis as measured by gas exchange and chlorophyll fluorescence (2010) M. Possell, A. Ryan, C. Vickers, P. Mullineaux and C.N. Hewitt, Photosynthesis Research, 104, 49-59, doi 10.1007/s11120-009-9504-5

Large estragole fluxes from oil palms in Borneo (2010) P. K. Misztal, S. M. Owen, A. B. Guenther, R. Rasmussen, C. Geron, P. Harley, G. J. Phillips, A. Ryan, D. P. Edwards, C. N. Hewitt, E. Nemitz, J. Siong, M. R. Heal, and J. N. Cape, Atmospheric Chemistry and Physics, 10, 4343-4358

NOx and O3 above a tropical rainforest: an analysis with a global and box model (2010) R. C. Pike, J. D. Lee, P. J. Young, G. D. Carver, N. Warwick, S. Moller, P. Misztal, B. Langford, D. Stewart, C. E. Reeves, C. N. Hewitt, and J. A. Pyle, Atmospheric Chemistry and Physics, 10, 10607-10620

Effects of climate-induced changes in isoprene emissions after the eruption of Mount Pinatubo (2010) P. J. Telford, J. Lathiere, N. L. Abraham, P. Braesicke, C. E. Johnson, O. Morgenstern, F. M. O’ Connor, R. C. Pike, O. Wild, P. Young, D. Beerling, C. N. Hewitt, and J. Pyle, Atmospheric Chemistry and Physics, 10, 7117 – 7125, doi:10.5194/acp-10-7117-2010

Genetic structure and regulation of isoprene synthase in Poplar (Populus spp. (2010) C. Vickers, M. Possell, P. Mullineaux and C.N. Hewitt Plant Molecular Biology, 73, 547 - 558 doi10.1007/s11103-010-9642-3

Fluxes and concentrations of volatile organic compounds from a south-east Asian tropical rainforest (2010) B. Langford, P. Misztal, D. Davison, C. Helfter, T.A.M. Pugh, A.R. MacKenzie and C.N. Hewitt, Atmospheric Chemistry and Physics, 10, 8391 - 8412

Sensitivity of isoprene emission estimated using MEGAN to the time resolution of input climate data (2010) K. Ashworth, O. Wild and C.N. Hewitt, Atmospheric Chemistry and Physics, 10, 1193-1201

Simulating atmospheric composition over a South-East Asian tropical rainforest: performance of a chemistry box model (2010) T. A. M. Pugh, A. R. MacKenzie, C. N. Hewitt, B. Langford, P. M. Edwards, K. L. Furneaux, D. E. Heard, J. R. Hopkins, C. E. Jones, A. Karunaharan, J. Lee, G. Mills, P. Misztal, S. Moller, P. S. Monks and L. K. Whalley, Atmospheric Chemistry and Physics, 10, 279-298

Oxidant and particle photochemical processes above a south-east Asian tropical rain forest (the OP3 project): introduction, rationale, location characteristics, tools and overview (2010) C. N. Hewitt, J. D. Lee, A. R. MacKenzie, M. P. Barkley, N. Carslaw, G. D. Carver, N. A. Chappell, H. Coe, C. Collier, R. Commane, F. Davies, B. Davison, P. DiCarlo, C. F. Di Marco, J. R. Dorsey, P. M. Edwards, M. J. Evans, D. Fowler, K. L. Furneaux, M. Gallagher, A. Guenther, D. E. Heard, C. Helfter, J. Hopkins, T. Ingham, M. Irwin, C. Jones, A. Karunaharan, B. Langford, A. C. Lewis, S. F. Lim, S. M. MacDonald, A. S. Mahajan, S. Malpass, G. McFiggans, G. Mills, P. Misztal, S. Moller, P. S. Monks, E. Nemitz, V. Nicolas-Perea, H. Oetjen, D. E. Oram, P. I. Palmer, G. J. Phillips, R. Pike, J. M. C. Plane, T. Pugh, J. A. Pyle, C. E. Reeves, N. H. Robinson, D. Stewart, D. Stone, L. K. Whalley, and X. Yang, Atmospheric Chemistry and Physics, 10, 169 - 199

Nitrogen management is essential to prevent tropical oil palm plantations from causing ground level ozone pollution (2009) C.N. Hewitt, A. MacKenzie, P. Di Carlo, C. Di Marco, J. Dorsey, M. Evans, D. Fowler, M. Gallagher, J. Hopkins, C. Jones, B. Langford, J. Lee, A.C. Lewis, S. Lim, J. McQuaid, P. Misztal, S. Moller, P.S. Monks, E. Nemitz, D. Oram, S. Owen, G. Phillips, T. Pugh, J.A. Pyle, C. Reeves, J. Ryder, J. Siong, U. Skiba and D. Stewart, Proceedings of the National Academy of Sciences of the United States of America, 106, 18447 – 18451, doi: 10.1073/pnas.0907541106

Uptake of aldehydes and ketones at typical indoor concentrations by houseplants (2009) A. Tani and C.N. Hewitt, Environmental Science and Technology, 43, 8338 – 8343, doi: 10.1021/es9020316

Sensitivity of isoprene emissions from the terrestrial biosphere to 20th century changes in atmospheric CO2 concentration, climate, and land use (2010) J. Lathière, C. N. Hewitt, and D. J. Beerling, Global Biogeochemical Cycles, 24, GB1004, doi:10.1029/2009GB003548

Fluxes and concentrations of volatile organic compounds above central London, UK (2010) B. Langford, E. Nemitz, E. House, G. Phillips, D. Famulari, B. Davison, J. R. Hopkins, A. C. Lewis, and C.N. Hewitt, Atmospheric Chemistry and Physics, 10, 627-645

Development and application of a Lagrangian model to determine the origins of ozone episodes in the UK (2010) J. Strong, J.D. Whyatt, C.N. Hewitt and R.G. Derwent, Atmospheric Environment, 44, 631 – 641, doi:10.1016/j.atmosenv.2009.11.019

Concentrations and emissions of volatile organic compounds from a Mediterranean ecosystem in western Italy (2009) B. Davison, R. Taipale, B. Langford, P. Misztal, S. Fares, G. Matteucci, F. Loreto, J.N. Cape, J. Rinne and C.N. Hewitt, Biogeosciences, 6, 1655 – 1670

Defining hybrid poplar (Populus deltoids x Populus trichocarpa) tolerance to ozone: identifying key parameters (2009) A. Ryan, C. Cojocariu, M. Possell, W. Davies and C.N. Hewitt, Plant, Cell and Environment, 32, 31 - 45

Biogenic volatile organic compounds in the Earth system: a Tansley Review (2009) J. Laothawornkitkul, J.E. Taylor, N.D. Paul and C. N. Hewitt, New Phytologist, 183, 27 – 51, doi: 10.1111/j.1469-8137.2009.02859.x

Mixing ratios and eddy covariance flux measurements of volatile organic compounds from an urban canopy (Manchester, U.K.) (2009) B. Langford, B. Davison, E. Nemitz and C.N. Hewitt, Atmospheric Chemistry and Physics, 9, 1971 - 1987

Gas exchange and photosynthetic performance of the tropical tree Acacia nigrescens when grown in different CO2 concentrations (2009) M. Possell and C.N. Hewitt, Planta, 229, 837 – 846 doi: 10.1007/s00425-008-0883-1

Isoprene synthesis protects transgenic tobacco plants from oxidative stress (2009) C. Vickers, M. Possell, C. Cojocariu, V.B Velikova, J. Laothawornkitkul, A. Ryan, P. Mullineaux and C.N. Hewitt, Plant Cell and Environment, 32, 520 – 531, doi: 10.1111/j.1365-3040.2009.01946.x

Discrimination of plant volatile signatures by an electronic nose: a potential technology for plant pest and disease monitoring (2008) J. Laothawornkitkul, J.P. Moore, J.E. Taylor, M. Possell, T.D. Gibson, C. N. Hewitt, and N.D. Paul, Environmental Science and Technology, 22, 8433 – 8438

The role of isoprene in plant herbivory (2008) J. Laothawornkitkul, N. Paul. C. Vickers, M. Possell, P. Mullineaux, C.N. Hewitt and J. Taylor, Plant Signalling and Behavior, 3, 1141-1142

Isoprene emission deters plant herbivory (2008) J. Laothawornkitkul, C. Vickers, M. Possell, N. Paul, J. Taylor, P. Mullineaux and C.N. Hewitt, Plant, Cell and Environment, 31, 1410-1415

Assessing, mapping and quantifying the distribution of foliar biomass in Great Britain (2008) H. Stewart, C.N. Hewitt and R.G.H. Bunce, Biomass and Bioenergy, 32, 838-856, doi:10.1016/j.biombioe.2007.12.015

The effect of trade between China and the UK on national and global carbon dioxide emissions (2008) Y. Li and C.N. Hewitt, Energy Policy, 36, 1907 - 1914