Masters Thesis Abstract: Kreepa Shrestha
The contribution of micro- scale activities to personal exposure in commuting micro- environments
People spend a substantial amount of their outdoor time in the transport micro-environment, and exposure to pollutants in this micro-environment are often highly elevated compared to elsewhere. This results in individuals gaining a significant contribution of their daily exposure in a short period of time. Several conclusions can be drawn from studies of human exposure to the exhaust and evaporative emissions of motor vehicles. Firstly, it is important to realise that fixed site ambient air quality monitors do not adequately characterize human exposure to certain air pollutants. Past research has demonstrated very high concentrations of CO and other pollutants in poorly ventilated, confined spaces used by motor vehicles. These include parking garages, tunnels and underpasses. Previous studies have also indicated that public transport commuters are potentially exposed to higher levels of pollutants while they are waiting at bus stops and train stations. To date, no research of this type has been undertaken in New Zealand. The proposed research will extend and complement the existing current knowledge base and will assist in providing information about hazardous micro-activities that lead to peaks in pollutant exposures. Additionally, this project will also assess the comparative risk associated with exposure to traffic pollution when traveling on different transport modes, namely cycle, car, bus and train. Specifically, my research intends to identify peaks in pollutant exposure in each journey and to establish key events responsible for such pollution ‘spikes’. Additionally, I also aim to study how and to what extent confined spaces such as sheltered car parks and bus/ train stations affect a commuter’s total daily exposure. This research will assist in assessing major health implications based on how commuters choose to travel, while helping transport decision-making at personal and societal levels.
The project employed a variety of pollution monitoring equipment to measure concentrations of key traffic- related pollutants: particulate matter (PM1, PM2.5 and PM10), ultra fine particles and carbon- monoxide. All three measures of vehicle pollution were simultaneously measured and all samplers were co-located to ensure consistency. Sampling was carried out in Christchurch and Auckland. The relatively flat topography of Christchurch, along with a high number of cyclists assisted in establishing clear relationships between transport modes and pollution exposure. Similarly, the heightened traffic pollution in Auckland and its large population, along with its rain network and the Northern Busway made Auckland an ideal sampling location. My research commenced on December 1st 2009. A working draft of a review of the relevant literature has been completed as has the sampling fieldwork in both Christchurch and Auckland. The next step involves the correcting and analyzing of the data collected.