Rosie Lewis

Rosie Lewis


Second year PhD researcher in Volcanology, Institute of Geophysics and Tectonics, University of Leeds. The aim of my PhD project is to conduct a detailed health hazard assessment of the concentrations, compositions and spatiotemporal dispersion of volcanic air pollution on Montserrat to advise local agencies on human health risks and the potential need to install an operational network of air pollution sensors. This study focuses on sulphur dioxide (SO2) and particulate matter (PM) as air pollutants. 

During my May 2023 field campaign, I worked with local collaborators at Montserrat Volcano Observatory and the Disaster Management and Co-ordination Agency to calibrate and install a network of 13 air quality monitors around the island, to be left for two years. I am in the process of developing a method to calibrate the data produced by the 11 lower-cost instruments to that of the 2 reference grade instruments on-island, during a series of colocation experiments. Direct samples for geochemical analyses were also collected across the island using the filter-pack method, to gather both ambient and point-source samples. I will process these samples using compositional analyses (ICP-MS) to determine relative toxicity.

I am continuing to work with local stakeholders on this project, through the ongoing logistical support of the Montserrat Volcano Observatory, the input of the 6 local government agencies who attended our workshop at the beginning of the 2023 field campaign, and local educational institutions and media (ZJB radio) with whom outreach activities were completed. 

Research interests

Whilst large, explosive eruptions attract public interest in volcanism, chronic, invisible hazards such as long-term exposures to toxic volcanic gases often remain unnoticed, understudied and thus unaccounted for. The Montserrat government has expressed concerns that its citizens and visitors are chronically exposed to volcanic air pollutants as the Soufrière Hills volcano continues to degas, despite not having erupted ash since 2010. The gas plume typically follows the trade winds westward into the abandoned capital of Plymouth, but residents report odours of sulphurous gases in the north of the island with changes in the wind direction. Measurements taken by the Montserrat Volcano Observatory (MVO) indicate that the volcano is emitting ~ 440 tonnes per day of sulphur dioxide (SO2) with recent spikes reaching up to 1000 tonnes per day. No particulate air quality assessment has been conducted on island for many years and ongoing SO2 diffusion tube monitoring efforts are not sensitive to real-time fluctuations. It is currently unknown whether airborne volcanic pollutants – in particular SO2 and particulate matter (PM), including ash and sulphate aerosol - could be present in concentrations, durations or frequencies of concern to the health of the Montserrat population.

Research Questions:

  • How do SO2 and PM concentrations vary spatially and temporally on Montserrat?
  • How does the geochemical composition of PM affect health risk?
  • How can past and present air pollution data be used to inform current and future health risk?


  • BSc Geography, University of Manchester.
  • MPhil Holocene Climates, University of Cambridge

Research groups and institutes

  • Institute for Climate and Atmospheric Science
  • Institute of Geophysics and Tectonics