Mobile sources of atmospheric polycyclic aromatic hydrocarbons: a roadway tunnel study

Suspended particulate matter and vapor samples were collected in a heavily traveled roadway tunnel and analyzed for polycyclic aromatic hydrocarbons (PAHs). The vapor phase samples were found to contain high levels of phenanthrene and methyl- and dimethylphenanthrenes. The particulates could be classified into two groups: one containing alkylated phenanthrenes from diesel fuel, and another consisting of high molecular weight PAHs from gasoline emissions. In general, PAH levels had declined by a factor of between 5 and 10 since 1975 due to the use of catalytic converters in automobiles.