I read with interest the recently published report, from Imperial College, listing the relative densities of pollution in differing modes of transportation. You can see the BBC summary at the following link - http://news.bbc.co.uk/1/hi/health/4598388.stm.
Why do we care about this? Well, as it happens there is a link between traffic pollution and cancer, according to the report here - http://news.bbc.co.uk/1/hi/health/4368093.stm
The first report, which can be accessed from Imperial College itself here is an investigation into the amount of particulates that occur in the environment around people, the team analysed taxi, bus, cycling, walking, and private car use. Whether traffic fumes scale in a linear fashion with the ultrafine particulates sampled in the experiments is unclear. What is interesting is the findings of the report.
