Simultaneous Quantification of Real-World Elemental Contributions from the Exhaust and Non-Exhaust Vehicular Emissions Using Road Dust Enrichment Factor-Elemental Carbon Tracer Method (EFECT)

Abstract

Emission control regulations have been essential in reducing vehicular exhaust emissions. However, the contribution of exhaust and non-exhaust emissions to ambient particulate matter (PM) has not yet been accurately quantified due to the lack of standardized sampling and measurement methods to set regulations. The identified sources and the source profiles generated have not been comparable as none of the emission data collection techniques and the receptor models applied in the literature have produced a standard or reference method to simultaneously identify and quantify the non-exhaust emission sources. This study utilized and thoroughly characterized PM samples including 32 major and trace elements from a mixed fleet in a mountain highway tunnel atmosphere in Bolu, Türkiye. This work proposed a two-stage, simple, and robust method based on road dust enrichment factor (EF) and elemental carbon (EC) tracer methods (EFECT) for the identification and prediction of the exhaust (exh), and non-exhaust (n-exh) emissions in PM. The indicated method revealed that road dust resuspension emissions are the most significant contributor to the concentrations of crustal elements. This method was used successfully to determine the real-world elemental contributions of road dust resuspension (rdrs), emissions (em), exhaust (exh), and non-exhaust (n-exh) emission sources to the elemental concentrations in PM samples. This study provided significant insights into generating actual source profiles, source-specific emission factors, and the source apportionment results for vehicular emission sources worldwide. Considering this, PM data of any particle size fraction (PM10, PM10-2.5, and PM2.5, for example) can be used as input for the EFECT, provided that the data include the analytical results of elemental carbon in both the atmospheric PM and road dust samples having similar PM sizes.