Dr Stephen Ball

I obtained my PhD in the group of Gus Hancock (Oxford University) studying ozone photochemistry. This work significantly contributed to a revision of the recommended quantum yields for O(1D) at near-UV wavelengths and hence a better understanding of the production rates of OH radicals in the atmosphere.  

During a post-doctoral fellowship with Fred Eisele at NCAR (Colorado), I measured gas-to-particle nucleation rates of sulphuric acid aerosol. We showed that the presence of a base, in this case ammonia, greatly increased nucleation rates in the ternary H₂SO₄/H₂O/NH₃ system.

I returned to the UK to work with Rod Jones (Cambridge University) to pioneer the use of broadband light sources in cavity ringdown and cavity enhanced absorption spectroscopy. We developed several instruments, mainly based on light emitting diodes (LEDs), targeting atmospheric trace gases including NO₂, NO₃, N₂O₅ and molecular iodine (I₂).

Subsequently, I was appointed to a lectureship in the School of Chemistry, University of Leicester. My research group continues to use instruments based on broadband cavity enhanced absorption spectroscopy to measure atmospheric trace gases in field studies (NO₂, HONO, I₂); for instrument inter-comparison and calibrations (NO₂, ClNO₂, glyoxal); and laboratory studies of atmospheric reactions and biogenic emissions (reactive iodine emissions).

The Earth’s atmosphere is a complex and ever-changing mixture of gases and aerosol particles. Our research studies reactive trace gases emitted into the atmospheric from natural sources and anthropogenic (human-made) sources, and the photochemical processes that determine how quickly chemistry removes these and other gases from the atmosphere.

Areas of interest are:

Laboratory experiments to quantify the emission rates of reactive iodine species (I₂ and HOI) released when ozone reacts with iodide in seawater. Reaction at the ocean surface is a sink of ground-level tropospheric ozone, and so too is the atmospheric chemistry initiated by photolysis of the emitted iodine species. These natural sink processes are important in a world where tropospheric ozone concentrations are increasing due to anthropogenic emissions of nitrogen oxides.

• Radical chemistry and ozone production at a UK coastal receptor site, Woodward-Massey R.; Sommariva R.; Whalley L.K.; Cryer D.R.; Ingham T.; Bloss W.J.; Ball S.M.; Cox S.; Lee J.D.; Reed C.P.; Crilley L.R.; Kramer L.J.; Bandy B.J.; Forster G.L.; Reeves C.E.; Monks P.S.; Heard D.E., Atmospheric Chemistry and Physics, 23, 14393 (2023) https://doi.org/10.5194/acp-23-14393-2023

• Is the ocean surface a source of nitrous acid (HONO) in the marine boundary layer? Crilley L.R.; Kramer L.J.; Pope F.D.; Reed C.; Lee J.D.; Carpenter L.J.; Hollis L.D.J.; Ball S.M.; Bloss W.J., Atmospheric Chemistry and Physics, 21, 18213 (2021) https://doi.org/10.5194/acp-21-18213-2021

• Enhanced wintertime oxidation of VOCs via sustained radical sources in the urban atmosphere, Sommariva R.; Crilley L.R.; Ball S.M.; Cordell R.L.; Hollis L.D.J.; Bloss W.J.; Monks P.S., Environmental Pollution, 274, 116563 (2021) https://doi.org/10.1016/j.envpol.2021.116563

• Marine iodine emissions in a changing world, Carpenter L.J.; Chance R.J.; Sherwen T.; Adams T.J.; Ball S.M.; Evans M.J.; Hepach H.; Hollis L.D.J.; Hughes C.; Jickells T.D.; Mahajan A.; Stevens D.P.; Tinel L.; Wadley M.R., Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 477, 20200824 (2021) https://doi.org/10.1098/rspa.2020.0824

• Influence of the Sea Surface Microlayer on Oceanic Iodine Emissions, Tinel L.; Adams T.J.; Hollis L.D.J.; Bridger A.J.M.; Chance R.J.; Ward M.W.; Ball S.M.; Carpenter L.J., Environmental Science and Technology, 54, 13228 (2020) https://dx.doi.org/10.1021/acs.est.0c02736

• Nitrous acid (HONO) emissions under real-world driving conditions from vehicles in a UK road tunnel, Kramer L.J.; Crilley L.R.; Adams T.J.; Ball S.M.; Pope F.D.; Bloss W.J., Atmospheric Chemistry and Physics, 20, 5231 (2020) https://doi.org/10.5194/acp-20-5231-2020

I teach on multiple modules in the areas of physical chemistry and atmospheric chemistry (* indicates module convenor). I am also the School of Chemistry’s Senior Tutor with responsibility for our personal tutoring provision and the Student-Staff Committee.

CH1204 Maths and Skills *

CH1207 Sustainable and Environmental Chemistry

CH3203 Advanced Physical Chemistry *

CH4203/CH7303 Earth System Science *

Supervisor for research projects in Year 3 BSc/MChem and Year 4 MChem.

• BA (Oxford)
• DPhil (Oxford)
• Fellow of the Higher Education Academy.