Re-evaluating effectiveness of vehicle emission control programmes targeting high-emitters

Huang, Yuhan; Surawski, Nicholas C.; Yam, Yat Shing; Lee, Casey K.C.; Zhou, John L.; Organ, Bruce; Chan, Eric

doi:10.1038/s41893-020-0573-y

Cited by 40 publications

(36 citation statements)

References 20 publications

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“…Among them, road transport is the most affected sector. Road transport is a major source of air pollution in urban areas [5][6][7] and has a severe adverse effect on the public health due to its close proximity to the people [8,9]. Thus, it is widely perceived that the pandemic lockdowns would help mitigate the air pollution problem.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty in the Impact of the COVID-19 Pandemic on Air Quality in Hong Kong, China

Huang

Zhou

et al. 2020

Atmosphere

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Strict social distancing rules are being implemented to stop the spread of COVID-19 pandemic in many cities globally, causing a sudden and extreme change in the transport activities. This offers a unique opportunity to assess the effect of anthropogenic activities on air quality and provides a valuable reference to the policymakers in developing air quality control measures and projecting their effectiveness. In this study, we evaluated the effect of the COVID-19 lockdown on the roadside and ambient air quality in Hong Kong, China, by comparing the air quality monitoring data collected in January–April 2020 with those in 2017–2019. The results showed that the roadside and ambient NO2, PM10, PM2.5, CO and SO2 were generally reduced in 2020 when comparing with the historical data in 2017–2019, while O3 was increased. However, the reductions during COVID-19 period (i.e., February–April) were not always higher than that during pre-COVID-19 period (i.e., January). In addition, there were large seasonal variations in the monthly mean pollutant concentrations in every year. This study implies that one air pollution control measure may not generate obvious immediate improvements in the air quality monitoring data and its effectiveness should be evaluated carefully to eliminate the effect of seasonal variations.

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Section: Introductionmentioning

confidence: 99%

Uncertainty in the Impact of the COVID-19 Pandemic on Air Quality in Hong Kong, China

Huang

Zhou

et al. 2020

Atmosphere

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“…From this perspective, this work is distinct from previous attempts that introduced spatial surrogates for traffic states (e.g., floating cars and traffic congestion index in opensource maps) to fill the monitoring gaps. Other key input data are the vehicle-specific category that is closely related to vehicle-specific emission factors (Huang et al, 2020 According to the license plate, the identified vehicle category is verified via the I/M data. Herein, six vehicle categories were detected and defined, including light-duty vehicles (LDVs), middle-duty vehicles (MDVs), heavy-duty vehicles (HDVs), light-duty trucks (LDTs), middle-duty trucks (MDTs), and heavyduty trucks (HDTs).…”

Section: Hyperfine-resolution Bottom-up Model Frameworkmentioning

confidence: 99%

Hyperfine-Resolution Mapping of On-Road Vehicle Emissions with Comprehensive Traffic Monitoring and Intelligent Transportation System

Jiang

Xia

Wang

et al. 2021

Preprint

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Abstract. Urban on-road vehicle emissions affect air quality and human health locally and globally. Such emissions typically exhibit distinct spatial heterogeneity, varying sharply over short distances (10 m ~ 1 km). However, all-around observational constraints on the emission sources are limited in much of the world. Consequently, traditional emission inventories lack the spatial resolution that can characterize on-road vehicle emission hotspots. Here we establish a bottom-up approach to reveal a unique pattern of urban on-road vehicle emissions at 1 ~ 3 orders of magnitude higher spatial resolution than current inventories. We interconnect all-around traffic monitoring (including traffic fluxes, vehicle-specific categories, and speeds) via an intelligent transportation system (ITS) over the Xiaoshan District in the Yangtze River Delta (YRD) region. This enables us to calculate single-vehicle-specific emissions over each fine-scale (10 m ~ 1 km) road segment. Thus, a hyperfine emission dataset is achieved, and on-road emission hotspots appear. The resulting map shows that the hourly average on-road vehicle emissions of CO, NOx, HC, and PM2.5 are 74.01 kg, 40.35 kg, 8.13 kg, and 1.68 kg, respectively. More importantly, widespread and persistent emission hotspots emerge, of significantly sharp small-scale variability, up to 8 ~ 15 times, attributable to distinct traffic fluxes, road conditions, and vehicle categories. On this basis, we investigate the effectiveness of routine traffic control strategies on the on-road vehicle emission mitigation. Our results have important implications for how the strategies should be designed and optimized. Integrating our traffic-monitoring-based approach with urban air quality measurements, we could address major data gaps between urban air pollutant emissions and concentrations.

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“…The International Energy Agency estimated that global energy consumption more than doubled during 1971 to 2015, and the percentage of energy use by the transport sector increased noticeably from 23% to 29% during the same period while other sectors mostly did not change [8]. Vehicle engines are also a major contributor to urban air pollution, posing a serious health hazard to the public [9,10]. A recent study estimated that vehicle tailpipe emissions caused 385000 premature deaths and US$1 trillion of health damage worldwide in 2015 [11].…”

Section: Introductionmentioning

confidence: 99%

Dual injection: An effective and efficient technology to use renewable fuels in spark ignition engines

Huang

Surawski

Zhuang

et al. 2021

Renewable and Sustainable Energy Reviews

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Modern spark ignition engines mostly use one injection system to deliver gasoline into the combustion chamber, using either direct injection or port fuel injection. Both technologies have their respective advantages. To integrate their advantages and to promote the use of renewable fuels, dual injection engines are in development in recent years. Dual injection represents an advanced combustion system and is a novel technology to address the urgent issues of sustainability and environmental protection. This study reviews the state-of-the-art research on dual injection spark ignition engines with a focus on renewable fuels, their advantages and engine performance. The main advantages of dual injection include greater control flexibility, enhanced cooling effect, knock mitigation, engine downsizing, extended lean-burn limits, higher thermal efficiency and reductions of several emission species. The most promising renewable fuels for dual injection are ethanol, methanol and hydrogen. Each renewable fuel is aimed at different advantages of dual injection.Alcohol-gasoline dual injection provides great anti-knock ability by taking advantage of alcohols' large enthalpies of vaporisation and high octane numbers, while hydrogen-gasoline dual injection provides extended lean-burn limits by taking advantage of hydrogen's low ignition energy, wide flammability limit and high flame speed. Direct injection of renewable fuels is the optimal injection strategy because it effectively utilises the strong cooling effect of alcohols or avoids the volumetric efficiency reduction and preignition of hydrogen. Dual injection generally demonstrates higher thermal efficiency than single injection.In addition, dual injection effectively reduces particulate emissions while there are usually trade-offs among gaseous emissions.

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Re-evaluating effectiveness of vehicle emission control programmes targeting high-emitters

Cited by 40 publications

References 20 publications

Uncertainty in the Impact of the COVID-19 Pandemic on Air Quality in Hong Kong, China

Uncertainty in the Impact of the COVID-19 Pandemic on Air Quality in Hong Kong, China

Hyperfine-Resolution Mapping of On-Road Vehicle Emissions with Comprehensive Traffic Monitoring and Intelligent Transportation System

Dual injection: An effective and efficient technology to use renewable fuels in spark ignition engines

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