The use of fixed air pollution monitors to assess population exposure to pollution may result in significant errors because actual exposure for individuals depends on their activities and distances from emissions source locations. To investigate personal exposure to air pollution, this study: (i) evaluates the accuracy of personal exposure measuring instruments by comparisons to reference instruments; (ii) measures the variation in personal exposure to black carbon (BC) in three different UK cities along different transport modes and routes; (iii) evaluates exposure along a specific walking route in Marylebone, measuring BC and lung deposited surface area (LDSA); and (iv) investigates the spatial distribution of nitrogen dioxide (NO2) measured by diffusion tubes in Marylebone.
BC levels measured by the portable exposure instrument (AE 51) were higher than those measured by the reference instrument by approximately 14% to 16%. BC concentrations recorded on four different transport modes in different cities showed large variation. Walking on quiet streets led to the lowest mean BC exposure when compared with any other route in every city. Children are found to be exposed to higher BC concentrations than adults when walking on the busy streets. On the walking route in Marylebone, BC and LDSA are more highly correlated on busy streets compared to streets with low traffic volumes, which indicate that a greater proportion of the LDSA is BC when closer to transport emissions. Finally, the NO2 measurements indicate that road-side concentrations are higher than urban background values over the entire period.
This thesis indicates that personal exposure cannot be accurately predicted with fixed monitoring stations and that there is significant variability in exposure at different times of the day and along different routes, heavily influenced by transport emissions.