Multi-pollutant emission characteristics of non-road construction equipment based on real-world measurement

Non-road construction equipment (NRCE) has become a crucial contributor to urban air pollution. However, the cur-rent research on NRCE is still in its infancy, and the understanding of its pollutant emissions is not yet clear. In thisstudy, multi-pollutant (CO, HC, NOx, PM2.5, and BC) and CO2 emissions from 12 excavators and 9 loaders underreal-world conditions are investigated by using a synchronous platform based on portable emission measurement sys-tem (SP-PEMS). Wefind the instantaneous emission rates of multi-pollutant present significant variability under different operation modes, and pollutant emissions are significantly high under cold start. Generally, multi-pollutantemission factors (EFs) have been all effectively reduced with the tightening of emission standards except for CO and NOx. The BC and PM2.5 emissions are significantly affected by engine types, and those emitted by electronically-controlled fuel injection (EI) engines are at lower concentration levels compared with mechanical fuel injection(MI) engines. The mass ratios of BC/PM2.5 for EI engines are 2.05 times that for MI engines on average. Through comparison, we find the multi-pollutant EFs of NRCE reported by different studies and the Guide vary greatly, and those recommended by the Guide may be overestimated or underestimated to varying degrees. Finally, we recommend the multi-pollutant EFs of NRCE under different emission standards by combining the results of various studies, and which will provide scientific support for the accurately establish of emission inventory