| Abstract: | Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDF) were determined in air at the inlet and outlet of a longitudinally ventilated tunnel with separate tubes for each traffic direction. In addition, measurements of traffic density, traffic composition, ventilation rate and other air pollutants were carried out. The data allowed to estimate the PCDD/PCDF emissions based on a car fleet of about 20'–30'000 cars. Furthermore, the varying percentage of heavy duty vehicles made it possible to differentiate between emission factors for light (LDV) and heavy duty (diesel) vehicles (HDDV). Depending on driving conditions, the estimated emission factors were in the order of 0.04–0.5 ng/km 2,3,7,8-TEQ (Nordic model) for LDV and 0.8–9.5 ng/km for HDDV. |
