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 PM2.5 of NRCM. The results show that the fuel-based average emission factors (EFs) of carbon monoxide (CO), hydrocarbon (HC), nitrogen oxides (NOx), 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 NOx EF implies that the regulation of NOx emission in Wuhan should be strengthened. In addition, the PM2.5 chemical composition profiles for NRCM show that the PM2.5 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 PM2.5 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.