The effect of the environment factors upon ambulance despatches in London and Thailand

This thesis investigates environmental risk factors for human health. In particular, it investigates the role of extreme temperatures, air pollution and precipitation upon health. The research uses ambulance dispatch data as the indicator of health. Previous studies investigating the association between environmental factors (temperature, air pollution and rainfall) and adverse health outcomes have focused mainly on mortality and hospital admission data. Previously, relatively little research has examined the role of environmental factors upon ambulance dispatches. This study provides three distinct ambulance dispatch studies using data from various locations. Firstly, the association between air pollution and ambulance dispatches was conducted by using a systematic review and meta-analysis using data from all global sources. Secondly, a time series analysis was applied to analyse the impact of extreme temperature (low and high) on London Ambulance Service (LAS) data. Thirdly, the Thai ambulance dispatches in the Northern and Southern provinces were used to assess the association between rainfall and road accidents. Throughout the thesis, the estimated risk is reported as relative risk (RR) with 95% confidence intervals due to exposure to environmental factors such as extreme low and high temperatures, increased level of pollutants and an increase in rainfall. The main results reported are that, from a global systematic review, PM2.5 and NO2 are significantly associated with all-respiratory and asthma dispatches, respectively, for ambulance dispatch data. CO, PM2.5 and coarse particles are significantly associated with cardiac arrest dispatch data. In London, extreme temperatures have a significant association with an increase in ambulance dispatches. For example, low temperature was significantly associated with an increase in ambulance dispatches for 999, asthma, dyspnoea, RCI and ‘generally unwell’ while ambulance dispatches for 999, red, COPD, chest pain and non-cardiorespiratory category showed a significant increase for high temperatures. Moreover, in Thailand road accidents were significantly associated with rainfall.” The results from this thesis will help public health services understand the role of the environment upon health as they can be used in environmental surveillance and early warning systems. This will help achieve an effective preparation of the emergency service under climate change. The outcomes provide new knowledge that can be used to raise awareness on how to mitigate environmental risks. This knowledge can help improve worldwide ambulance services, especially in low and middle-income countries, notably Thailand