Inventory and emission factors of creosote, polycyclic aromatic hydrocarbons (PAH), and phenols from railroad ties treated with creosote

Inventory, emission factors, and total yearly emissions of creosote, PAH, a nd phenols from the Swiss railway network were determined based on the anal ysis of cross sections of selected railroad ties which were in use for up t o 46 years. Approximately 9 million wooden railroad ties are installed in S witzerland, each being treated with roughly 15 kg of creosote. During the s ervice time of a typical railroad tie of 20-30 years, about 5 kg of creosot e are emitted, corresponding to an emission factor of 208 mg/(m(2) x day). PAH emissions occur as emissions of the volatile 2- and 3-ring PAH (such as naphthalene, acenaphthylene, acenaphthene, anthracene, fluorene, phenanthr ene; boiling point up to 340 degreesC). PAH emissions for an average railro ad tie were found to be about 0.5 kg (sum of 16 EPA-PAH), corresponding to an emission factor of 20.3 mg/(m(2) x day). Emissions of phenolic compounds were determined to be in the range of 10 g for each tie, corresponding to an emission factor of 0.58 mg/(m(2) x day). According to our study, about 1 710 t of creosote components are being emitted by the ties of the Swiss rai lway network, every year. Based on the Values reported above, yearly emissi ons of 2- and bring EPA-PAH add up to 139 t Cumulated emissions of phenolic compounds are in the order of 4 t per year.