Real-world emission for in-use non-road construction machinery in Wuhan, China

Non-road construction machinery (NRCM) emissions pollutants significantly impact air quality. Six typical NRCM (2 excavators, 3 loaders, and 1 forklift) are analyzed based on a portable emission measurement system (PEMS) in Wuhan to estimate the real-world emission characteristics and chemical composition of PM_2.5 of NRCM. The results show that the fuel-based average emission factors (EFs) of carbon monoxide (CO), hydrocarbon (HC), nitrogen oxides (NO_x), and particulate matter (PM) are 19.4 ~ 35.7 g kg^-1 fuel, 2.9 ~ 7.9 g kg^-1 fuel, 57.5 ~ 95.3 g kg^-1 fuel, and 1.8 ~ 2.6 g kg^-1 fuel for the tested NRCM. The high NO_x EF implies that the regulation of NO_x emission in Wuhan should be strengthened. In addition, the PM_2.5 chemical composition profiles for NRCM show that the PM_2.5 emitted from NRCM is dominated by organic carbon and elemental carbon (56.11 ~ 73.85%), followed by water-soluble ions (WSIs, 1.47 ~ 3.46%), and elements (0.16 ~ 0.41%). The major WSIs species are Cl^-, Na⁺ and NO₃^-, and the major elements are Ca, Na, and K, which are important markers for PM_2.5 source analysis. The results of EFs and chemical composition emission characteristics of NRCM tailpipe pollutants obtained in the real-world can provide essential data support for accurately establish of emission inventory of non-road mobile sources in Wuhan.