Ultrafine particle exposure inside automobiles

There is an accumulating body of work suggesting that a large proportion of many people's daily exposure to ultrafine (<100nm) particles (UFPs) is incurred during the relatively short period of time spent travelling in an automobile (vehicle). Based on toxicological and epidemiological studies, UFPs are increasingly viewed as a significant risk to public health.However, despite the substantial contribution to total exposure that vehicle travel may constitute, the factors controlling the magnitude of in-vehicle UFP exposures have not been well-documented to-date. The effects of travel through road tunnels (a location where pollutant emissions are often elevated due to their constrained geometry) on daily UFP exposures have not been investigated, despite the increasing number and length of tunnels worldwide. This thesis takes a synergistic and measurement-oriented approach to elucidate the key factors underpinning in-vehicle UFP exposure during tunnel travel that is also relevant to all roadway environments.