Emission Measurements on a Large Sample of Heavy-Duty Diesel Trucks in China by Using Mobile Plume Chasing.

Real-world heavy-duty diesel trucks (HDTs) were found to emit far more excess nitrogen oxides (NO) and black carbon (BC) pollutants than regulation limits. It is essential to systematically evaluate on-road NO and BC emission levels for mitigating HDT emissions. This study launched 2109 plume chasing campaigns for NO and BC emissions of HDTs across several regions in China from 2017 to 2020. It was found that NO emissions had limited reductions from China III to China V, while BC emissions of HDTs exhibited high reductions with stricter emission standard implementation. This paper showed that previous studies underestimated 18% of NO emissions in China in 2019 and nearly half of the real-world NO emissions from HDTs (determined by updating the emission trends of HDTs) exceeded the regulation limits. Furthermore, the ambient temperature was identified as a primary driver of NO emissions for HDTs, and the low-temperature penalty has caused a 9-29% increase in NO emissions in winter in major regions of China. These results would provide important data support for the precise control of the NO and BC emissions from HDTs.