Assessing heavy-duty vehicles (HDVs) on-road NOx emission in China from on-board diagnostics (OBD) remote report data

Wang, Junfang; Wang, Rui; Yin, Heqi; Wang, Yunjing; Wang, Hongli; He, Chaohua; Liang, Jindong; He, Daiping; Yin, Hong; He, Kebin

doi:10.1016/j.scitotenv.2022.157209

Cited by 29 publications

(7 citation statements)

References 24 publications

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“…Considering the huge proportion of in-use vehicles and the relative lack of effective regulatory approaches, emission control against in-use diesel trucks will be essential to mitigate vehicle exhaust pollution. Nowadays, remote on-board diagnostic (OBD) is increasingly becoming an important way in China to monitor the real-time operating and emission conditions of in-use heavy-duty vehicles [11,12]. The data collected from OBD are also proven to be consistent with that obtained from portable emission measurement systems (PEMS) [13].…”

Section: Introductionmentioning

confidence: 80%

Impact of Illegal Application of Urea Regulator on Real-World Exhaust Nitrogen Oxygen and Particle Number Emissions

Fang

Yang

et al. 2022

Atmosphere

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Urea regulators (UR) have generally been employed against diesel trucks to save urea usage and thus contribute to the reduction in excessive emissions, while their usage is generally difficult to supervise and enforce. By conducting real driving emission measurements on a China IV heavy-duty diesel truck, a “trade-off” effect caused by UR was found between nitrogen oxides (NOx) and particle number (PN) emissions. The usage of UR contributes to 1.04 times higher NOx but 0.28 times lower PN emissions for the whole trip. In particular, the increasing effects on NOx are most efficient on the highway and least effectual on the urban road, while the decreasing effects on PN exhibit an opposite trend under different road types. From low- and medium- to the high-speed bin, the peak average vehicle-specific power NOx emission rates exhibit markedly increasing but slightly decreasing trends for the truck with and without UR, respectively. Furthermore, the NOx emissions in units of CO2 and the linear correlational relationship between CO2 and NOx instantaneous mass emission rates, especially those on the highway, are significantly enhanced. This study directly clarifies the effects of UR on real-world emissions, providing a scientific basis for the real-time identification of the malfunction of the selective catalytic reduction system.

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Section: Introductionmentioning

confidence: 80%

Impact of Illegal Application of Urea Regulator on Real-World Exhaust Nitrogen Oxygen and Particle Number Emissions

Fang

Yang

et al. 2022

Atmosphere

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“…Since 2000, China has implemented a strategy centered on a series of LDVs emission standards, which have been continually improved, to substantially reduce emissions of air pollutants from vehicles. , Emissions have dropped significantly during the upgrade process from CHINA 1 to CHINA 6a standard. − Starting from July 1, 2023, the CHINA 6b standard has been fully implemented, and vehicles that do not meet this standard can not be eligible for sale, registration, or licensing . In comparison with emission standards in developed countries like Europe and the United States, the CHINA 6b standard is even more stringent in some indicators, , particularly for passenger vehicles with very low emission limits. Similarly, whether to adopt the CHINA 7 LDVs standard as an upgrade to CHINA 6b is currently a topic of significant interest in China.…”

Section: Introductionmentioning

confidence: 97%

Upgrading Passenger Vehicle Emission Standard Helps to Reduce China’s Air Pollution Risk from Uncertainty in Electrification

Xie,

Chen,

Dai

et al. 2024

Environ. Sci. Technol.

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Upgrading to the CHINA 7 standard is crucial for managing air pollution from passenger vehicles in China. Meanwhile, China aims to achieve carbon neutrality by 2060, which necessitates large-scale replacement of gasoline vehicles with electric vehicles in the future. Consequently, the public might view upgrading gasoline vehicles to the CHINA 7 standard as redundant. However, the emission reduction benefits of upgrading standards in the context of uncertain electrification ambitions have not received adequate attention. Here, we show that upgrading standards will compensate for the absence of emissions reductions due to hindered electrification efforts. In the best scenario, China's CO 2 emissions can be reduced to 0.047 Gt and NO x to 8.2 × 10 3 t in 2050. In nonextreme electrification scenarios with CHINA 7 standard, the emission intensity reduction will remain the main driver for emission reductions, outweighing the electrification contribution. In extreme electrification scenarios, upgrading standards will tackle the increased emissions from plug-in hybrid electric vehicles. Our fleet-level results advocate for early standards upgrades to enhance resilience against air pollution risks arising from uncertainties in electrification. Our evidence from China, with one of the most stringent emission standards, can provide a reference point for the world on the upgrading passenger vehicle emission standard issue.

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“…However, real-world NOx emissions from diesel vehicles often exceed the corresponding emission limits, − challenging the expected environmental benefits from the deployment of stringent emission regulations. ,, The existing in-use inspection or testing methods either have a short testing time or a limited sample size, which cannot effectively cover the complex driving conditions and vehicle conditions in the real world. − For example, yearly inspection, remote sensing, and plume chasing , have been widely used for in-use emission measurement campaigns, which capture vehicle emissions under designated test cycles or short driving episodes and risk taking unrepresentative in-use emission results because of the short sampling time range. Portable emissions measurement system (PEMS) tests have been implemented in recent regulations, but PEMS programs are not economically feasible to cover a long period (e.g., >1 day) or massive vehicle samples.…”

Section: Introductionmentioning

confidence: 99%

Regulatory Insights for On-Board Monitoring of Vehicular NOx Emission Compliance

Zhao,

Wu,

Zhang

et al. 2024

Environ. Sci. Technol.

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Nitrogen oxide (NOx) emissions from heavy-duty diesel vehicles (HDDVs) have adverse effects on human health and the environment. On-board monitoring (OBM), which can continuously collect vehicle performance and NOx emissions throughout the operation lifespan, is recognized as the core technology for future vehicle in-use compliance, but its large-scale application has not been reported. Here, we utilized OBM data from 22,520 HDDVs in China to evaluate their real-world NOx emissions. Our findings showed that China VI HDDVs had a 73% NOx emission reduction compared with China V vehicles, but a considerable proportion still faced a significant risk of higher NOx emissions than the corresponding limits. The unsatisfactory efficiency of the emission treatment system under disadvantageous driving conditions (e.g., low speed or ambient temperature) resulted in the incompliance of NOx emissions, especially for utility vehicles (sanitation/garbage trucks). Furthermore, the observed intertrip and seasonal variability of NOx emissions demonstrated the need for a long-term continuous monitoring protocol instead of instantaneous evaluation for the OBM. With both functions of emission monitoring and malfunction diagnostics, OBM has the potential to accurately verify the in-use compliance status of largescale HDDVs and discern the responsibility of high-emitting activities from manufacturers, vehicle operators, and driving conditions.

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Assessing heavy-duty vehicles (HDVs) on-road NOx emission in China from on-board diagnostics (OBD) remote report data

Cited by 29 publications

References 24 publications

Impact of Illegal Application of Urea Regulator on Real-World Exhaust Nitrogen Oxygen and Particle Number Emissions

Impact of Illegal Application of Urea Regulator on Real-World Exhaust Nitrogen Oxygen and Particle Number Emissions

Upgrading Passenger Vehicle Emission Standard Helps to Reduce China’s Air Pollution Risk from Uncertainty in Electrification

Regulatory Insights for On-Board Monitoring of Vehicular NOx Emission Compliance

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