Source identification and quantification of real-world PAH contributions from traffic-related exhaust and non-exhaust emission sources using the EFECT method

Abstract

Proper identification of sources and their contribution to atmospheric gaseous and particle-bound PAHs from traffic-related sources are vital for controlling and reducing emissions in the urban atmosphere to improve environmental health. For this purpose, we used the EFECT method to quantify the PAH contributions from the pre-defined vehicular sources, namely, road dust resuspension, exhaust (tailpipe), and non-exhaust sources in a rural highway tunnel. We successfully quantified the relative source contributions of particle-bound and total PAHs (particulate plus gaseous PAHs) to the atmospheric concentrations. Study results showed that exhaust emissions were observed to be the most important emission source for both particle-bound and total PAHs. This study showed that exhaust emission sources contribute 92.4% of IcdP, 90.3% of Phe, 89.9% of AN, 89.1% of BkF, 88.2% of Np, 87.1% of Ane, 86.3% of DahA, 85.7% of BghiP, and 82.8% of Flr to atmospheric concentrations in the tunnel environment. Road dust resuspension contributed mainly to TSP (total suspended particulate matter) concentrations of BaA (29.1%), Py (28.9%), BbF (21.0%), and BaP (21.0%).