Ollie Thwaites, PhD student at the Environment and Health Research Centre (ENVHE), spoke to us about his recent Master’s dissertation and how it sparked his interest in the use of GIS to explore the relationships between the natural environment and health.
Linking green space data from Ordnance Survey with records of birds, butterflies, and plants from the National Biodiversity Network Atlas
The idea for my dissertation project came about during the data visualization module. We were learning how to use Geographic Information Systems (GIS), to model and analyse spatial data. My undergraduate degree was in Biology, and I was keen to combine the knowledge gained during that with the new skills I was learning during the Master’s. So, I came up with the idea of linking green space data from Ordnance Survey with records of birds, butterflies and plants from the National Biodiversity Network Atlas. My exposures were calculated at the Lower Super Output Area (LSOA) level. I calculated the area of green space, and the species density of birds, butterflies, plants, and the total species density by dividing the number of species by the area of green space, within each LSOA.
Enriching the data
Following discussions with my supervisors, I linked the environmental exposures to data from the National Survey for Wales (NSW). The NSW is an annual survey of approximately 12,000 people, covering a range of topics such as culture, health and the environment. The Warwick-Edinburgh Mental Well-Being Scale (WEMWBS) is also included in the survey. WEMWBS is a validated scale used to measure mental well-being, and I used the scores from WEMWBS as my outcome. Socio-demographic data were available from the survey too, so I was able to adjust for age, sex, ethnicity and economic status. The NSW responses are available in the Secure Anonymised Information Linkage (SAIL) databank, housed here at Swansea University.
My results suggested that it is not the quantity of green space that was associated with mental well-being, but the quality of the green space was. Living in an LSOA with more plant species density was associated with better mental well-being in an adjusted model. I also performed a stratification analysis, separating the cohort into quintiles according to income group. I found a stronger association between plant species density and mental well-being for respondents in a low-income quintile compared with the full cohort mentioned previously. This finding supports previous research suggesting that people on lower incomes appear to benefit more from natural environments than people on higher incomes.
I recently gave a presentation of this work at the International Population Data Linkage Network Conference, with my abstract published in the International Journal of Population Data Science. I really enjoyed completing this piece of work, so much so that my PhD research is investigating a similar topic. In my PhD, I will be investigating how blue spaces
(e.g., the coast, lakes, rivers) affect physical health outcomes, building on the knowledge and skills I acquired previously to address a key gap in our knowledge of how the natural environment can benefit health.
Find out more about Ollie and the Environment and Health Research Centre (ENVHE) research.