Characterization of particulate smoke and the potential chemical fingerprint of non-road construction equipment exhaust emission in China

Abstract

Non-road construction equipment (NRCE) is an important source of atmospheric pollution in many developing and urbanizing countries such as China. However, NRCE source is frequently ignored and failed to be identified in the processing of the source apportionment for atmospheric pollution due to the little knowledge on its chemical fingerprint. In this study, seven types of NRCE are selected with the objectives of quantifying the emission factors of fine particulate matter (PM2.5) (EFPM) and exploring their potential chemical fingerprints. Our results show that the NRCE EFPM in the working modes are ~2–3 times higher than those in idling modes, suggesting the important role of engine operating conditions in producing primary PM2.5. As expected, carbonaceous aerosol is the dominant specie of PM2.5, with a wide range of 64–95%. And, the ratio of organic carbon to elemental carbon displays a systematical decrease trend with the increase of engine rated powers. The analysis results show that NRCE PM2.5 chemical compositions are highly correlated with the engine rated powers. In addition, we confirm that the ratio of vanadium and nickel can be used as a good tracer of NREC emission, which is distinct from other key combustion sources such as industry and ship emission. Taken together, this study reveals the emission characteristics of NRCE-related particles and urgently calls on that the NRCE source should be considered in the source apportionment models in the future.