Real world CO2 and NOx emissions from 149 Euro 5 and 6 diesel, gasoline and hybrid passenger cars

In this study CO₂ and NO_x emissions from 149 Euro 5 and 6 diesel, gasoline and hybrid passenger cars were compared using a Portable Emissions Measurement System (PEMS). The models sampled accounted for 56% of all passenger cars sold in Europe in 2016. We found gasoline vehicles had CO₂ emissions 13-66% higher than diesel. During urban driving, the average CO₂ emission factor was 210.5 (sd. 47) gkm^-1 for gasoline and 170.2 (sd. 34) gkm^-1 for diesel. Half the gasoline vehicles tested were Gasoline Direct Injection (GDI). Euro 6 GDI engines <1.4ℓ delivered ~17% CO₂ reduction compared to Port Fuel Injection (PFI). Gasoline vehicles delivered an 86-96% reduction in NO_x emissions compared to diesel cars. The average urban NO_x emission from Euro 6 diesel vehicles 0.44 (sd. 0.44) gkm^-1 was 11 times higher than for gasoline 0.04 (sd. 0.04) gkm^-1. We also analysed two gasoline-electric hybrids which out-performed both gasoline and diesel for NO_x and CO₂. We conclude action is required to mitigate the public health risk created by excessive NO_x emissions from modern diesel vehicles. Replacing diesel with gasoline would incur a substantial CO₂ penalty, however greater uptake of hybrid vehicles would likely reduce both CO₂ and NO_x emissions. Discrimination of vehicles on the basis of Euro standard is arbitrary and incentives should promote vehicles with the lowest real-world emissions of both NO_x and CO₂.

NOx, NH3, N2O and PN real driving emissions from a Euro VI heavy-duty vehicle. Impact of regulatory on-road test conditions on emissions

Euro VI emission standards for heavy-duty vehicles (HDVs) introduced for the first time limits for solid particle number (PN) and NH₃ emissions. EU regulation also includes a Portable Emissions Measurement System (PEMS) based test at type approval, followed by in-service conformity (ISC) testing. A comprehensive study on the real-time on-road emissions of NO_x, NH₃, N₂O and PN from a Euro VI HDV equipped with a Diesel Oxidation Catalyst (DOC), a Diesel Particle Filter (DPF), a Selective Catalytic Reduction (SCR) system and an Ammonia Oxidation Catalyst (AMOX) is presented. Our analyses revealed that up to 85% of the NO_x emissions measured during the tests performed are not taken into consideration if the boundary conditions for data exclusion set in the current legislation are applied. Moreover, it was found that the highest NO_x emissions were measured during urban operation. Analyses show that a large fraction urban of operation is not considered when 20% power threshold as boundary condition is applied. They also show that cold start emissions account for a large fraction of the total NO_x emitted. Low emissions of PN (2.8×10¹⁰ to 6.5×10¹⁰#/kWh) and NH₃ (1.0 to 2.2ppm) were obtained during the on-road tests, suggesting effectiveness of the vehicle's after-treatment (DPF and AMOX). Finally, a comparison between speed-based (as currently defined by Euro VI legislation) and land-use-based (using Geographic Information System (GIS)) calculation of shares of operation was performed. Results suggest that using GIS to categorize the shares of operation could result in different interpretations depending on the criteria adopted for their definition.

Characterization and carcinogenic risk assessment of polycyclic aromatic and nitro-polycyclic aromatic hydrocarbons in exhaust emission from gasoline passenger cars using on-road measurements in Beijing, China

The polycyclic aromatic hydrocarbon (PAH) and nitro-polycyclic aromatic hydrocarbon (NPAH) emissions from 16 gasoline passenger cars, encompassing five emission standards and two driving conditions, were tested using a portable emission measurement system (PEMS) in Beijing under on-road conditions. In total, 16 PAHs and 9 NPAHs were quantified in both the gaseous and particulate phases by high-performance liquid chromatography (HPLC). The results indicated that lower PAH and NPAH emissions were observed with improved emission standards, especially for China 3 to China 5 vehicles (P < 0.05). Higher emission factors (EFs) were detected on nonhighway roads than on highway roads due to incomplete combustion. Although most PAHs and NPAHs were in the gas-phase, the TEQ_BaP of the particulate-phase PAHs was 4.2 times higher than that of the gas-phase PAHs, whereas the opposite pattern was observed for NPAHs. The TEQ_BaP EFs on nonhighway roads were 1.0-2.3 times higher than those on highway roads. The results of this study will be valuable for estimating the emissions and performing carcinogenic risk assessment of PAHs and NPAHs from urban gasoline passenger cars on roads. Formulating more stringent regulations and emission control technologies for PAHs and NPAHs is important.

Characteristics of on-road NOx emissions from Euro 6 light-duty diesel vehicles using a portable emissions measurement system

This paper presents the on-road nitrogen oxides (NO_x) emissions measurements from Euro 6 light-duty diesel vehicles using a portable emissions measurement system on the predesigned test routes in the metropolitan area of Seoul, Korea. Six diesel vehicles were tested and the NO_x emissions results were analyzed according to the driving routes, driving conditions, data analysis methods, and ambient temperatures. Total NO_x emissions for route 1, which has higher driving severity than route 2, differed by -4-60% from those for route 2. The NO_x emissions when the air conditioner (AC) was used were higher by 68% and 85%, on average, for routes 1 and 2, respectively, compared to when the AC was not used. The analytical results for NO_x emissions by the moving averaging window method were higher by 2-31% compared to the power binning method. NO_x emissions at lower ambient temperatures (0-5°C) were higher by 82-192% compared to those at higher ambient temperatures (15-20°C). This result shows that performance improvements of exhaust gas recirculation and the NO_x after-treatment system will be needed at lower ambient temperatures.

Palatable Eating Motives Scale in a college population: Distribution of scores and scores associated with greater BMI and binge-eating

The main goal of this study was to provide distributive data for the Palatable Eating Motives Scale (PEMS) on a large (N=1947) ethnically-diverse college student population along with motive scores characteristic of obesity and binge-eating severity. Students completed the PEMS, or a revised version of the PEMS, the Binge Eating Scale, and reported height and weight for a body mass index (BMI). The PEMS identified Coping, Reward Enhancement, Social, and Conformity motives for eating tasty but unhealthy foods for reasons other than hunger. The revised PEMS (included here) had better goodness-of-fit with the motives. Percentile rankings are presented for each of the motive scores. Separate Coping scores are presented for females and males given a modest effect size for females to score higher. Generally, scores on Coping, Reward Enhancement, Conformity, and a total PEMS score in the 70th percentile (those scoring higher than 70% of the sample) were associated with obesity and severe binge-eating. Unlike these motives, Social scores were the highest at each percentile rank but unassociated with BMI or binge-eating, reflecting the culturally-normative intake of these foods for social reasons. These distribution scores on PEMS motives in college students along with scores linked to higher BMI and binge-eating severity represent the first reported data of this type. Knowledge of these scores can be used to individualize and correspondingly improve current strategies aimed at preventing and treating obesity, binge-eating, maladaptive use of food to regulate internal and external pressures, and to improve overall nutritional health.

Factors affecting emotional eating and eating palatable food in adults

BACKGROUND/OBJECTIVES

The aim of this study was to determine the relationship among emotional eating behavior, tendency to eat palatable foods, and several risk factors.

SUBJECTS/METHODS

This study was carried out on 2,434 persons (1,736 women and 698 men) aged between 19 and 64 years. A questionnaire form was used as a data collection tool, which consisted of items for the socio-demographic characteristics, anthropometric measurements, Emotional Appetite Questionnaire (EMAQ), and the Palatable Eating Motives Scale (PEMS).

RESULTS

A positive significant correlation was observed between the BMI groups and the negative emotions, negative situations, and negative total scores of EMAQ (P < 0.01). The regression results on negative subscales showed that a one unit increase in BMI resulted in a 0.293 unit increase in negative situations scores, a 0.626 unit increase in negative emotions scores, and a 0.919 unit increase in negative total EMAQ scores. When the BMI groups and PEMS subscale scores were examined, a significant relationship was found in the social motives, rewarding, and conformity subscales (P < 0.01). A one unit increase in BMI increased the coping motives scores by 0.077 units.

CONCLUSIONS

The emotional states have a significant effect on the eating behavior. On the other hand, an increase in eating attacks was observed, particularly in people who were under the effect of a negative emotion or situation. Nevertheless, there were some limitations of the study in terms of quantitative determination of the effects of this eating behavior depending on the BMI.

Real-world NOx emissions from heavy-duty diesel, natural gas, and diesel hybrid electric vehicles of different vocations on California roadways

This study assessed the real-world nitrogen oxide (NOx) emissions from 50 heavy-duty vehicles of different vocations and engine technologies using portable emissions measurement systems (PEMS). This is one of the most comprehensive in-use emissions studies conducted to date, which played a key role in the development of CARB's (California Air Recourses Board) updated EMission FACtor (EMFAC) model, especially for natural gas vehicles. In-use emissions testing was performed on school and transit buses, refuse haulers, goods movement vehicles, and delivery vehicles while were driven over their normal operating routes in the South Coast Air Basin. Engine technologies included diesel engines with and without selective catalytic reduction (SCR) systems, compressed natural gas (CNG) engines and liquified petroleum gas (LPG) engines, and SCR-equipped diesel hybrid electric vehicles. For most vehicles, the in-use NOx emissions were higher than the certification standards for the engine. Diesel vehicles generally showed higher brake-specific NOx emissions compared to the CNG vehicles. NOx emissions were strongly dependent on the SCR temperature, with SCR temperatures below 200 °C resulting in elevate brake-specific NOx. The 0.02 g/bhp-hr certified CNG vehicles showed the largest reductions in NOx emissions. The diesel hybrid electric vehicles showed important distance-specific NOx benefits compared to the conventional diesel vehicles, but higher emissions compared to the CNG and LPG vehicles. Overall, average NOx reductions were 75%, 94%, 65%, 79%, respectively, for the 0.2 CNG, 0.02 CNG, diesel hybrid electric, and LPG vehicles compared to diesel vehicles, due in part to some diesel vehicles with particularly high emissions, indicating that the widespread implementation of advanced technology and alternative fuel vehicles could provide important NOx reductions and a path for meeting air quality targets in California and elsewhere.

The control of precerebellar neuron migration by RNA-binding protein Csde1

Neuronal migration during brain development sets the position of neurons for the subsequent wiring of neural circuits. To understand the molecular mechanism regulating the migrating process, we considered the migration of mouse precerebellar neurons. Precerebellar neurons originate in the rhombic lip of the hindbrain and show stereotypic, long-distance tangential migration along the circumference of the hindbrain to form precerebellar nuclei at discrete locations. To identify the molecular components underlying this navigation, we screened for genes expressed in the migrating precerebellar neurons. As a result, we identified the following three genes through the screening; Calm1, Septin 11, and Csde1. We report here functional analysis of one of these genes, Csde1, an RNA-binding protein implicated in the post-transcriptional regulation of a subset of cellular mRNA, by examining its participation in precerebellar neuronal migration. We found that shRNA-mediated inhibition of Csde1 expression resulted in a failure of precerebellar neurons to complete their migration into their prospective target regions, with many neurons remaining in migratory paths. Furthermore, those that did reach their destination failed to invade the depth of the hindbrain via radial migration. These results have uncovered a crucial role of Csde1 in the proper control of both radial and tangential migration of precerebellar neurons.

Study on real-world power-based emission factors from typical construction machinery

Construction machinery accounts for a large share of the non-road machinery market and is an important pollutant source. In this study, real-world emission tests were undertaken on 16 excavators and 19 wheel loaders by using a portable emission measurement system (PEMS) to obtain their real-world engine performance and emission factors. The typical operating modes were categorized as idling, moving and working modes. The results show that in the working mode, the engine continuously operated at a high speed, high torque and high load factor, which led to sharp up and down CO, HC, NO_x and particle number (PN) emissions. As the emission standards were strengthened, the CO, HC and NO_x emissions clearly decreased, and the excavators and wheel loaders showed a higher emission level in the moving mode. A comparison of the excavator and wheel loader in China III displayed that the CO, HC, and NO_x total emission factors of the wheel loader were 10.20, 2.70 and 1.79 times higher than those of the excavator, respectively, so the wheel loader contributed more seriously to environmental pollution. The CO and HC measured emission factors of the excavators and wheel loaders were 0.05-1.38 times and 0.13-0.58 times higher than the corresponding Limitation and the recommended values from the national emission inventory Guideline. However, the NO_x emission factors were 1.20-3.25 times higher than the corresponding Limitation and the recommended value from the Guideline, which means that the recommended values overestimate CO and HC, and underestimate NO_x. A comparison of the emission factors of the excavators and wheel loaders in this study with others demonstrate that the CO and HC power-based emission factors were generally lower, but the NO_x emission factor was higher.

Characterization of the emissions impacts of hybrid excavators with a portable emissions measurement system (PEMS)-based methodology

Hybrid engine technology is a potentially important strategy for reduction of tailpipe greenhouse gas (GHG) emissions and other pollutants that is now being implemented for off-road construction equipment. The goal of this study was to evaluate the emissions and fuel consumption impacts of electric-hybrid excavators using a Portable Emissions Measurement System (PEMS)-based methodology. In this study, three hybrid and four conventional excavators were studied for both real world activity patterns and tailpipe emissions. Activity data was obtained using engine control module (ECM) and global positioning system (GPS) logged data, coupled with interviews, historical records, and video. This activity data was used to develop a test cycle with seven modes representing different types of excavator work. Emissions data were collected over this test cycle using a PEMS. The results indicated the HB215 hybrid excavator provided a significant reduction in tailpipe carbon dioxide (CO₂) emissions (from -13 to -26%), but increased diesel particulate matter (PM) (+26 to +27%) when compared to a similar model conventional excavator over the same duty cycle.

Epidemiological aspects of astrovirus and coronavirus in poults in the South Eastern Region of Brazil

A survey of Turkey Coronavirus (TCoV) and Astrovirus (TAstV-2) prevalence was carried out from February to December during 2006 year in semiarid region of Brazil, from a turkey producer area, localized in South Eastern of Brazil. To asses the risk factor related to clinical material, climatic condition and type of RT-PCR applied, cloacal swabs (CS), faeces, sera, bursa of Fabricius (BF), thymus (TH) and spleen (SP) and ileum-caeca region were collected from 30-day-old poults suffering of enteritis episode characterized as poult enteritis mortality syndrome (PEMS). The PEMS clinical features were characterized by watery to foamy faeces, light brown-yellow in colour and low mortality rate. Meteorological data (rainfall and relative humidity) observed during along the study presented monthly average temperature ranging from 39.3 and 31.2ºC, precipitation in rainy season from 40 to 270.3 mm/month, and no rain during dry season. Simplex RT-PCR gave odds ratio (OR) values suggesting that ileum-caeca region is at higher chance (OR=1.9; p=0.9741) to have both viral RNA than faeces (OR=1.5; p=0.7319). However, multiplex RT-PCR showed 3.98 (p=0.89982) more chance to give positive results in faeces than CS at dry season. The major risk factors seem to be low rate of humidity and high temperatures at winter, probably responsible for spread, easily, the TCoV and TAstv-2 among the flocks. The positive results of both virus suggested that they can play an important role in enteric disorders, associated to low humidity and high temperatures frequently found in tropical countries.

Characterization of the chemical composition of PM2.5 emitted from on-road China III and China IV diesel trucks in Beijing, China

The composition of diesel exhaust fine particulate matter (PM2.5) is of growing interest because of its impacts on health and climatic factors and its application in source apportionment and aerosol modeling. We characterized the detailed chemical composition of the PM2.5, including the organic carbon (OC), elemental carbon (EC), water-soluble ions (WSIs), and elemental contents, emitted from China III and China IV diesel trucks (nine each) based on real-world measurements in Beijing using a portable emissions measurement system (PEMS). Carbonaceous compounds were the dominant components (totaling approximately 87%) of the PM2.5, similar to the results (greater than 80% of the PM2.5) of our previous study of on-road China III diesel trucks. In general, the amounts of individual component groups (carbonaceous compounds, WSIs, and elements) and PM2.5 emissions for China IV diesel trucks were lower than those of China III diesel trucks of the same size, except for the WSIs and elements for the light- and medium-duty diesel trucks. The EC/OC mass ratios were strongly dependent on the emission standards, and the ratios of China IV diesel trucks were higher than those of China III diesel trucks of the same size. The chemical species in the PM2.5 were significantly affected by the driving conditions. Overall, the emission factors (EFs) of the PM2.5 and OC under non-highway (NHW) driving conditions were higher than those under highway (HW) driving conditions, and the EC/OC mass ratios presented an increasing trend, with decreasing OC/PM2.5 and increasing EC/PM2.5 from NHW to HW driving conditions; similar trends were reported in our previous study. In addition, Pearson's correlation coefficients among the PM2.5 species were analyzed to determine the relationships among the various chemical components.

Real-world gaseous and particulate emissions from Euro IV to VI medium duty diesel trucks

This study offers emission factors for earlier and late technology medium duty diesel particulate filter (DPF) -equipped trucks, operating on real-world conditions. The analysis includes levels of nitrous oxide (N₂O) emissions as well as the impacts of DPF regenerations on emission levels. The real-driving gaseous and particulate emissions, as well as fuel consumption of 14 Euro IV, Euro V, and Euro VI medium duty diesel trucks were analysed and the efficiency of different emission control technologies were assessed. Measurements were conducted using portable emission measurement systems (PEMS) over a wide range of driving and operating conditions. Distance-based integration of emission rates over 500 m sections was considered for statistical analysis, providing a large dataset of emission factors to be used for network link-based traffic and emissions modelling. In terms of emissions performance, nitrogen oxides (NO_x) levels were in general above the corresponding Euro standard limits, while carbon monoxide (CO), total hydrocarbons (THC) and particulate matter (PM) levels were within limits. Selective catalytic reduction (SCR) -equipped Euro V vehicles were seen to emit more than their non-SCR-equipped counterparts. NO_x and fuel consumption were positively correlated with road gradient over the -6% to 6% gradient range. The emission levels of ammonia (NH₃) were measured significantly lower than the respective Euro VI provisions for heavy duty engines, while the N₂O levels were found to contribute approximately 1% to the respective total greenhouse gases levels. DPF regeneration events in real world seem to have a measurable impact mostly on THC and PM emissions, increasing baseline levels by 8.1% and 29%, respectively, for Euro VI vehicles.

Estimating the effectiveness of vehicle emission regulations for reducing NOx from light-duty vehicles in Korea using on-road measurements

The South Korean government has reinforced emission regulations for newly manufactured vehicles to reduce air pollution from automobiles. The government has applied different emission regulations depending on the fuel, following the regulations set for gasoline vehicles in California, USA, and those set for diesel vehicles in the European Union (EU). In this study, the on-road NOx emissions of 109 light-duty vehicles in South Korea were measured on roads in Seoul and the surrounding metropolitan area using a portable emissions measurement system (PEMS). The results were then analyzed to evaluate the effectiveness of the emission regulations introduced in Korea for NOx reduction. The average on-road NOx emissions for the Euro 5 and Euro 6b diesel vehicles were approximately five times higher than the laboratory emission limits set by the EU regulation. The NOx emissions also showed significant variation depending on the driving parameters, such as the driving dynamics and the ambient temperature. From the Euro 6d-TEMP regulation in which the real driving emissions-light duty vehicles (RDE-LDV) regulatory package was implemented, the average on-road NOx emissions from the diesel vehicles were controlled within the laboratory emission limits, but were still higher than those of the gasoline vehicles. Despite the absence of the RDE-LDV regulations, the average on-road NOx emissions of the gasoline vehicles that had ultra-low emission vehicle (ULEV) and super ultra-low emission vehicle (SULEV) standard certifications were controlled within the laboratory emission limits set by the FTP-75, regardless of the various driving parameters. The results of this study show that it is necessary to include a wide range of driving conditions in emission certification test procedures, such as RDE-LDV, and enhance the regulatory measures that enable manufacturers to maintain the effectiveness of emission control systems.

Comparison of real-world and certification emission rates for light duty gasoline vehicles

U.S. light duty vehicles are subject to the U.S. Environmental Protection Agency (EPA) emission standards. Emission compliance is determined by certification testing of selected emissions from representative vehicles on standard driving cycles using chassis dynamometers. Test results are also used in many emission inventories. The dynamometer based emission rates are adjusted to provide the certification levels (CL), which must be lower than the standards for compliance. Although standard driving cycles are based on specific observations of real-world driving, they are not necessarily real-world representative. A systematic comparison of the real-world emission rates of U.S. light duty gasoline vehicles (LDGVs) versus CL, and emission standards has not been previously reported. The purpose of this work is to compare regulatory limits (both CLs and emission standards) and the real-world emissions of LDGVs. The sensitivity of the comparisons to cold start emission was assessed. Portable Emission Measurement Systems (PEMS) were used to measure hot stabilized exhaust emissions of 122 LDGVs on a specified 110 mile test route. Cold start emissions were measured with PEMS for a selected vehicle sample of 32 vehicles. Emissions were measured for carbon dioxide (CO₂), carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO_x). For each vehicle, a Vehicle Specific Power (VSP) modal emission rate model was developed. The VSP modal rates were weighted by the standard driving cycles and real-world driving cycles to estimate the respective cycle average emission rates (CAERs). Measured vehicles were matched with certification test vehicles for comparison. For systematic trends in comparison, vehicles were classified into four groups based on the Tier 1 and Tier 2 emission regulation, and the vehicle type such as passenger car and passenger truck. Depending on the cycle-pollutant and the vehicle groups, hot stabilized CAERs are on average either statistically significantly higher than or significantly not different from the CLs, with the exception of CO on the US06 cycle, for which real-world rates are lower than CLs. Compared to the emission standards, hot stabilized CAERs are on average significantly lower. However, comparisons of CAERs and standards are sensitive to cold start emissions. For some combinations of pollutants and vehicle groups, cold start inclusive CAERs are higher than the corresponding CLs and as high as the standards. The CLs, which are based on standard driving cycles, tend to underestimate real-world emission rates. Therefore, emission inventory estimates using certification test results are potentially underestimated.

Reducing vehicle fuel consumption and exhaust emissions from the application of a green-safety device under real driving

Vehicle emissions have a significantly negative impact on climate change, air quality and human health. Drivers of vehicles are the last major and often overlooked factor that determines vehicle performance. Eco-driving is a relatively low-cost and immediate measure to reduce fuel consumption and emissions significantly. This paper reports investigation of the effects of an on-board green-safety device on fuel consumption and emissions for both experienced and inexperienced drivers. A portable emissions measurement system (PEMS) was installed on a diesel light goods vehicle (LGV) to measure real-driving emissions (RDE), including total hydrocarbons (THC), CO CO₂, NO, NO₂ and particulate matter (PM). In addition, driving parameters (e.g. vehicle speed and acceleration) and environmental parameters (e.g. ambient temperature, humidity and pressure) were recorded in the experiments. The experimental results were evaluated using the Vehicle Specific Power (VSP) methodology to understand the effects of driving behavior on fuel consumption and emissions. The results indicated that driving behavior was improved for both experienced and inexperienced drivers after activation of the on-board green-safety device. In addition, the average time spent was shifted from higher to lower VSP modes by avoiding excessive speed, and aggressive accelerations and decelerations. For experienced drivers, the average fuel consumption and NO, NO₂ and soot emissions were reduced by 5%, 56%, 39% and 35%, respectively, with the on-board green-safety device. For inexperienced drivers, the average reductions were 6%, 65%, 50% and 19%, respectively. Moreover, the long-term formed habits of experienced drivers are harder to be changed to accept the assistance of the green-safety device, whereas inexperienced drivers are likely to be more receptive to change and improve their driving behaviors.

Study on pollutant emission characteristics of different types of diesel vehicles during actual road cold start

The current regulations of heavy-duty vehicles in China do not include the emissions in the cold start stage into the overall emission evaluation. However, the speed of heavy-duty diesel vehicles in the cold start stage is often low and the proportion of idle-conditions is large, resulting in the difference between the actual test results and evaluation results of emissions. Therefore, in order to accurately evaluate the impact of emission during cold start on the overall emission, in this study, the OBS-ONE portable vehicle emission test equipment was used to test the emission of three representative heavy-duty diesel vehicles with different types under actual road driving conditions, and the cumulative averaging (CA) method was adopted to calculate and analyze the test emission data. Firstly, the cold start emission of different types of heavy-duty vehicles was evaluated. The results show that the contribution rate of pollutant emission in the cold start stage is high, in which NOx emission accounts for 40-90% of the whole trip. It was unreasonable for regulations to exclude data in the cold start stage. The cold start duration of vehicle A is nearly 300 s longer than that of vehicle C, however, the NOx and PN emission factors of vehicle A are nearly 10 times and 100 times smaller than that of vehicle C at the cold start stage respectively. The cold start duration, fuel consumption and the emission factors in cold start stage of different types of heavy-duty diesel vehicles do not have a unified law. Secondly, the emission characteristics and differences of different types of heavy-duty vehicles are studied at the instantaneous level, and the internal mechanism causing the emission differences is explored and revealed. In the cold stage, CO₂ emission shows a good correlation with the fuel consumption. CO, NOx emissions show a good correlation with the fuel consumption when the engine and post-treatment temperature are low, and CO and NOx emissions decrease with the increase of engine and post-treatment temperature. PN emissions are mainly related to the engine working state. Finally, the influence of dynamic parameters v·a and RPA on pollutant emission was analyzed. The results show that driving force is an important factor affecting CO₂ emission, and RPA has no obvious correlation with emission at cold start stage.

Real-world emission characteristics of carbonyl compounds from agricultural machines based on a portable emission measurement system

Emissions of carbonyl compounds from agricultural machines cannot be ignored. Carbonyl compounds can cause the formation of ozone (O₃) and secondary organic aerosols, which can cause photochemical smog to form. In this study, 20 agricultural machines were tested using portable emission measurement system (PEMS) under real-world tillage processes. The exhaust gases were sampled using 2,4-dinitrophenylhydrazine cartridges, and 15 carbonyl compounds were analyzed by high-performance liquid chromatography. Carbonyl compound emission factors for agricultural machines were 51.14-3315.62 mg/(kg-fuel), and were 2.58 ± 2.05, 0.86 ± 1.07 and 0.29 ± 0.20 g/(kg-fuel) for China 0, China II and China III emission standards, respectively. Carbonyl compound emission factor for sowing seeds of China 0 agricultural machines was 3.32 ± 1.73 g/(kg-fuel). Formaldehyde, acetaldehyde and acrolein were the dominant carbonyl compounds emitted. Differences in emission standards and tillage processes impact ozone formation potential (OFP). The mean OFP was 20.15 ± 16.15 g O₃/(kg-fuel) for the China 0 emission standard. The OFP values decreased by 66.9% from China 0 to China II, and 67.4% from China II to China III. The mean OFP for sowing seeds of China 0 agricultural machines was 25.92 ± 13.84 g O₃/(kg-fuel). Between 1.75 and 24.22 times more ozone was found to be formed during sowing seeds than during other processes for China 0 and China II agricultural machines. Total carbonyl compound emissions from agricultural machines in China was 19.23 Gg in 2019. The results improve our understanding of carbonyl compound emissions from agricultural machines in China.

Evaluation of EDAR vehicle emissions remote sensing technology

Despite much work in recent years, vehicle emissions remain a significant contributor in many areas where air quality standards are under threat. Policy-makers are actively exploring options for next generation vehicle emission control and local fleet management policies, and new monitoring technologies to aid these activities. Therefore, we report here on findings from two separate but complementary blind evaluation studies of one new-to-market real-world monitoring option, HEAT LLC's Emission Detection And Reporting system or EDAR, an above-road open path instrument that uses Differential Absorption LIDAR to provide a highly sensitive and selective measure of passing vehicle emissions. The first study, by Colorado Department of Public Health and Environment and Eastern Research Group, was a simulated exhaust gas test exercise used to investigate the instrumental accuracy of the EDAR. Here, CO, NO, CH₄ and C₃H₈ measurements were found to exhibit high linearity, low bias, and low drift over a wide range of concentrations and vehicle speeds. Instrument accuracy was high (R² 0.996 for CO, 0.998 for NO; 0.983 for CH₄; and 0.976 for C₃H₈) and detection limits were 50 to 100ppm for CO, 10 to 30ppm for NO, 15 to 35ppmC for CH₄, and, depending on vehicle speed, 100 to 400ppmC₃ for C₃H₈. The second study, by the Universities of Birmingham and Leeds and King's College London, used the comparison of EDAR, on-board Portable Emissions Measurement System (PEMS) and car chaser (SNIFFER) system measurements collected under real-world conditions to investigate in situ EDAR performance. Given the analytical challenges associated with aligning these very different measurements, the observed agreements (e.g. EDAR versus PEMS R² 0.92 for CO/CO₂; 0.97 for NO/CO₂; ca. 0.82 for NO₂/CO₂; and, 0.94 for PM/CO₂) were all highly encouraging and indicate that EDAR also provides a representative measure of vehicle emissions under real-world conditions.

Pulsed Electrochemical Mass Spectrometry for Operando Tracking of Interfacial Processes in Small-Time-Constant Electrochemical Devices such as Supercapacitors

A more detailed understanding of the electrode/electrolyte interface degradation during the charging cycle in supercapacitors is of great interest for exploring the voltage stability range and therefore the extractable energy. The evaluation of the gas evolution during the charging, discharging, and aging processes is a powerful tool toward determining the stability and energy capacity of supercapacitors. Here, we attempt to fit the gas analysis resolution to the time response of a low-gas-generation power device by adopting a modified pulsed electrochemical mass spectrometry (PEMS) method. The pertinence of the method is shown using a symmetric carbon/carbon supercapacitor operating in different aqueous electrolytes. The differences observed in the gas levels and compositions as a function of the cell voltage correlate to the evolution of the physicochemical characteristics of the carbon electrodes and to the electrochemical performance, giving a complete picture of the processes taking place at the electrode/electrolyte interface.

Real-world emission characteristics of an ocean-going vessel through long sailing measurement

To quantify the emission characteristics of large ocean-going ships, onboard measurements were carried out for a large ocean-going vessel using portable emission measurement system (PEMS). The emission factors (EFs) of conventional pollutants and volatile organic compounds (VOCs) were greatly influenced by real-world operating conditions and engine loads. The sulfur dioxide (SO₂) and particulate matter (PM) emissions were mainly influenced by fuel type. The particle size distribution basically showed a single peak pattern, with nucleation mode particles as the main particles and the peak particle sizes ranging between 30 nm and 50 nm. The EFs for particle number (PN) ranged from 2.82 × 10¹⁶ to 4.49 × 10¹⁶ #/kwh. Carbonaceous components accounted for approximately 31.8% to 41.6% of the PM. SO₄^2-, NH₄⁺, Ca²⁺, Na⁺, and NO₃^- were dominant in water-soluble ions, while V and Ni were high-concentration metal elements, with the ratio of V: Ni ranging from 0.17 to 0.33. Increase in driving speed can lead to the increase in VOCs emissions. Our study presented a comprehensive test method with PEMS, which provides a reference for acquiring future real-world EFs. However, only one representative ship in China using a specific fuel was selected for the test, so it is important to characterize a broader range of ships and fuels.

Distance-based emission factors from vehicle emission remote sensing measurements

Vehicle emission remote sensing has the potential to provide detailed emissions information at a highly disaggregated level owing to the ability to measure thousands of vehicles in a single day. Fundamentally, vehicle emission remote sensing provides a direct measure of the molar volume ratio of a pollutant to carbon dioxide, from which fuel-based emissions factors can readily be calculated. However, vehicle emissions are more commonly expressed in emission per unit distance travelled e.g. grams per km or mile. To express vehicle emission remote sensing data in this way requires an estimate of the fuel consumption at the time of the emission measurement. In this paper, an approach is developed based on vehicle specific power that uses commonly measured or easily obtainable vehicle information such as vehicle speed, acceleration and mass. We test the approach against 55 independent comprehensive PEMS measurements for Euro 5 and 6 gasoline and diesel vehicles over a wide range of driving conditions and find good agreement between the method and PEMS data. The method is applied to individual vehicle model types to quantify distance-based emission factors. The method will be appropriate for application to larger vehicle emission remote sensing databases, thus extending real-world distance-based vehicle emissions information.

Modeling and predicting low-speed vehicle emissions as a function of driving kinematics

An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system (PEMS) under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics (speed and acceleration) of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data.

A comparison of a mini-PEMS and a 1065 compliant PEMS for on-road gaseous and particulate emissions from a light duty diesel truck

The primary goal of this study was to compare emissions measurements between a 1065 compliant PEMS, and the NTK Compact Emissions Meter (NCEM) capable of measuring NOx, PM, and solid PN. Both units were equipped on a light-duty diesel truck and tested over local, highway, and downtown driving routes. The results indicate that the NOx measurements for the NCEM were within approximately ±10% of those the 1065 compliant PEMS, which suggests that the NCEM could be used as a screening tool for NOx emissions. The NCEM showed larger differences for PM emissions on an absolute level, but this was at PM levels well below the 1 mg/mi level. The NCEM differences ranged from -2% to +26% if the comparisons are based on a percentage of the 1.0 mg/mi standard. Larger differences were also seen for PN emissions, with the NCEM measuring higher PN emissions, which can primarily be attributed to a zero current offset that we observed for the NCEM, which has been subsequently improved in the latest generation of the NCEM system. The comparisons between the 1065 compliant PEMS and the NCEM suggest that there could be applications for the NCEM or other mini-PEMS for applications such as identification of potential issues by regulatory agencies, manufacturer evaluation and validation of emissions under in-use conditions, and potential use in inspection and maintenance (I/M) programs, especially for heavy-duty vehicles.

Real-world gaseous emission characteristics of natural gas heavy-duty sanitation trucks

As compared to conventional diesel heavy-duty vehicles, natural gas vehicles have been proved to be more eco-friendly due to their lower production of greenhouse gas and pollutant emissions, which are causing enormous adverse effects on global warming and air pollution. However, natural gas vehicles were rarely studied before, especially through on-road measurements. In this study, a portable emission measurement system (PEMS) was employed to investigate the real-world emissions of nitrogen oxides (NOx) (nitrogen monoxide (NO), nitrogen dioxide (NO₂)), total hydrocarbons (THC), carbon monoxide (CO), and carbon dioxide (CO₂) from two liquified natural gas (LNG) China V heavy-duty cleaning sanitation trucks with different weight. Associated with the more aggressive driving behaviors, the vehicle with lower weight exhibited higher CO₂ (3%) but lower NOx (48.3%) (NO₂ (78.2%) and NO (29.4%)), CO (44.8%), and THC (3.7%) emission factors. Aggressive driving behaviors were also favorable to the production of THC, especially those in the medium-speed range but significantly negative to the production of CO and NO₂, especially those in the low-speed range with high engine load. In particular, the emission rate ratio of NO₂/NO decreased with the increase of speed/scaled tractive power in different speed ranges.