Unregulated Motor Vehicle Exhaust Gas Components

1990 ◽  
Author(s):  
D. Schuermann ◽  
K.-H. Lies ◽  
H. Klingenberg
Keyword(s):  
Motor Vehicle ◽  
Exhaust Gas ◽  
Vehicle Exhaust

Performance of Visible-Light-Driven Photocatalytic Pavement in Reduction of Motor Vehicles’ Exhaust Gas

2020 ◽  
Vol 2674 (11) ◽  
pp. 512-519
Author(s):  
Zhuoying Jiang ◽  
Xiong (Bill) Yu
Keyword(s):  
Absorption Spectrum ◽  
Visible Light ◽  
Motor Vehicle ◽  
Computational Simulation ◽  
Motor Vehicles ◽  
Traffic Density ◽  
Ultraviolet Region ◽  
Exhaust Gas ◽  
Vehicle Exhaust ◽  
Three Dimensional Model

Titanium dioxide (TiO2) is a widely used photocatalyst that can oxidize motor vehicle exhaust, for example, carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons, and sulfur dioxide, under the irradiation of sunlight. It has been reported that nano-scale TiO2 particles can be effectively used to modify the concrete-asphalt pavement, and make it as a photocatalytic pavement. However, the pure TiO2 additive limits its absorption spectrum to the ultraviolet region, which only occupies a small portion of sunlight irradiance. To increase the utilization of the full spectrum of sunlight, it has been demonstrated that doping TiO2 with substances such as Carbon (C), Nitrogen (N), or metal can reduce the band-gap and extend the threshold of the absorption spectrum to the visible light region. Therefore, doped-TiO2 has a better photocatalytic performance under sunlight irradiation. This paper conducted computational simulation of the kinetics of photocatalytic pavement to quantify the efficiency of doped-TiO2 embedded pavement in reducing exhaust gas from motor vehicles. A three-dimensional model is developed on a section of local road with doped-TiO2 embedded pavement. The effects of doped-TiO2 concentration, daylight conditions, and traffic flow conditions on the removal of NOx and CO were studied. The results indicate that the pavement with doped-TiO2 coating is effective to remove CO and NOx under different traffic density and daylight intensity conditions. Compared with UV activated TiO2, visible-light-activated doped-TiO2 features significantly higher removal efficiency of poisonous exhaustive gas including NOx and CO.

scholarly journals Molecular hydrogen (H<sub>2</sub>) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H<sub>2</sub>

2010 ◽  
Vol 10 (2) ◽  
pp. 3021-3051 ◽  
Author(s):  
M. K. Vollmer ◽  
S. Walter ◽  
S. W. Bond ◽  
P. Soltic ◽  
T. Röckmann
Keyword(s):  
Molecular Hydrogen ◽  
Motor Vehicle ◽  
Catalytic Converter ◽  
Anthropogenic Activities ◽  
Strong Dependence ◽  
Isotope Analysis ◽  
Geographical Location ◽  
Enrichment Factors ◽  
Exhaust Gas ◽  
Vehicle Exhaust

Abstract. Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO) and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H2 ranged from δD=–140‰ to δD=–195‰ upstream of the TWC but these values decreased to –270‰ to –370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O). In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ε) ranging from –39.8‰ to –15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of –270‰ (Rahn et al., 2002) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

scholarly journals Molecular hydrogen (H<sub>2</sub>) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H<sub>2</sub>

2010 ◽  
Vol 10 (12) ◽  
pp. 5707-5718 ◽  
Author(s):  
M. K. Vollmer ◽  
S. Walter ◽  
S. W. Bond ◽  
P. Soltic ◽  
T. Röckmann
Keyword(s):  
Molecular Hydrogen ◽  
Motor Vehicle ◽  
Catalytic Converter ◽  
Anthropogenic Activities ◽  
Strong Dependence ◽  
Isotope Analysis ◽  
Geographical Location ◽  
Enrichment Factors ◽  
Exhaust Gas ◽  
Vehicle Exhaust

Abstract. Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO), and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H2 ranged from δD = −140‰ to δD = −195‰ upstream of the TWC but these values decreased to −270‰ to −370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O). In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ε) ranging from −39.8‰ to −15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of −270‰ (Rahn et al., 2002) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

Deliberate Exposure to Motor Vehicle Exhaust Gas: The Psychosocial Profile of Attempted Suicide

1998 ◽  
Vol 32 (6) ◽  
pp. 830-838 ◽  
Author(s):  
Michaela A. Skopek ◽  
Richard Perkins
Keyword(s):  
Motor Vehicle ◽  
Adjustment Disorder ◽  
Motor Vehicles ◽  
Exhaust Gas ◽  
Psychological Autopsy ◽  
Vehicle Exhaust ◽  
Cross Sectional ◽  
Common Diagnosis ◽  
Suicide Note ◽  
Car Exhaust Gas

Objective: Deliberate exposure to motor vehicle exhaust gas has become the second most commonly used method of suicide in Australia. In an attempt to understand the factors contributing to the rise in popularity of this method, the psychosocial profiles, factors influencing method choice and circumstances of the act of self-harm were examined in a group of survivors. Method: A cross-sectional cohort study of 30 patients presenting for hyperbaric oxygen treatment having survived deliberate exposure to car exhaust gas was undertaken. A structured clinical interview was administered together with scales measuring depression, hopelessness and suicidal intent. Daily assessment of mental state and cognitive function was performed. Results: Factors common to the majority of subjects included male gender, age group of 20–50 years, and alcohol abuse. Relationship discord was the most common precipitating factor. Reasons given for choice of this method included the availability and accessibility of motor vehicles, painlessness, awareness that the method was lethal, knowledge of another person's successful suicide by this method and awareness of the method through media portrayal. Most of the cars used did not have engines fitted with catalytic converters, substantially increasing the risk of toxicity. Regret of the attempt, denial of further suicidal ideation after the event, and the absence of a suicide note were common findings. Most denied excessive time spent planning. The most common diagnosis in this group was adjustment disorder with depressed mood. Suicide intent scores were not high, inconsistent with the majority of patients being aware of the lethality of the method. Conclusion: Sociodemographic findings resemble those of psychological autopsy studies of subjects completing suicide by this method. Survival in this group was due to failure of the method or unexpected discovery rather than patient factors. This population described the method as highly acceptable and accessible emphasising the urgent need for reduction of access to this means of suicide in Australia.

Use of Multi-Rotor Unmanned Aerial Vehicles for Fine-Grained Roadside Air Pollution Monitoring

2019 ◽  
Vol 2673 (7) ◽  
pp. 169-180 ◽  
Author(s):  
Bai Li ◽  
Rong Cao ◽  
Zhanyong Wang ◽  
Rui-Feng Song ◽  
Zhong-Ren Peng ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Air Pollutants ◽  
Motor Vehicle ◽  
Gas Diffusion ◽  
Pollution Monitoring ◽  
Atmospheric Environment ◽  
Exhaust Pipe ◽  
Exhaust Gas ◽  
Vehicle Exhaust ◽  
Aerial Vehicles

With increasing numbers of motor vehicles, vehicle exhaust gas has become one of the most important sources of urban air pollutants. After being emitted from the motor vehicle, exhaust gas spreads through the air along the road and is gradually deposited in the surrounding area, having an adverse impact on pedestrians and residents. At present, most research on vehicle exhaust directly measures the total emissions from the exhaust pipe or monitors the time variation of air pollutants at the roadside by setting roadside monitoring stations. The spatial resolution of these two methods is very low, however, and it is impossible to describe accurately the diffusion patterns of exhaust gas in the atmosphere after discharge. Some scholars have conducted research on the quality of roadside air by hand-held portable devices, but these are limited by the speed of travel, and the spatial and temporal resolution of the acquired data is also very low. By using multi-rotor unmanned aerial vehicles (UAVs) and portable equipment, this study demonstrates an atmospheric environment monitoring system based on multi-rotor UAV by designing corresponding hardware circuits and software programs. With flexible requirements for takeoff or landing sites and high maneuverability of multi-rotor UAVs, the system increases the capability for high resolution spatial and temporal monitoring of the diffusion of traffic-emitted pollutants. The system can conduct fixed-point measurement by hovering, and can also measure air pollutants in complex urban terrain, providing an innovation in the study of vehicle exhaust gas diffusion.

scholarly journals Changes in suicide in England and Wales, 1960–1997

2000 ◽  
Vol 176 (1) ◽  
pp. 64-67 ◽  
Author(s):  
G. M. G. McClure
Keyword(s):  
Motor Vehicle ◽  
Age Groups ◽  
Exhaust Gas ◽  
Vehicle Exhaust ◽  
England And Wales ◽  
National Statistics ◽  
Suicide Rates ◽  
Males And Females ◽  
The 1960S ◽  
Methods Of Suicide

BackgroundMethods of suicide and suicide rates in England and Wales have fluctuated considerably since the 1960s.AimsTo review the changes that have occurred in suicide rates in England and Wales between 1960 and 1997.MethodSuicide rates, derived from total annual suicides and the estimated annual resident population, were obtained from the Office for National Statistics.ResultsSuicide rates decreased in both genders between the early 1960s and the mid-1970s. The rate for males then increased between 1975 and 1990, while the rate for females continued to fall. Between 1990 and 1997, the rate decreased for males and females in all age groups, particularly for those using motor vehicle exhaust gas; the latter finding is associated with increasing use of catalytic converters.ConclusionsFollowing the increase in suicide among males until 1990 there was a decrease for both genders between 1990 and 1997, consistent with the ‘Health of the Nation’ target.

Motor Vehicle Exhaust Gas Suicide

Crisis ◽  
2007 ◽  
Vol 28 (S1) ◽  
pp. 28-35 ◽  
Author(s):  
Virginia Routley
Keyword(s):  
Carbon Monoxide ◽  
Gas Sensors ◽  
Motor Vehicle ◽  
Exhaust Pipe ◽  
Exhaust Gas ◽  
Catalytic Converters ◽  
Prevention Measures ◽  
Vehicle Exhaust ◽  
Method Substitution ◽  
Methods Of Suicide

Abstract. In many motorized countries, inhalation of carbon monoxide from motor vehicle exhaust gas (MVEG) has been one of the leading methods of suicide. In some countries it remains so (e.g., Australia 16.0% of suicides in 2005). Relative to other methods it is a planned method and one often used by middle-aged males. The study provides a review of countermeasures aimed at restricting this method of suicide. The prevention measures identified were catalytic converters (introduced to reduce carbon monoxide for environmental reasons); in-cabin sensors; exhaust pipe modification; automatic idling stops; and helpline signage at suicide “hotspots.” Catalytic converters are now in 90% of new vehicles worldwide and literature supports them being associated with a reduction in exhaust-gassing suicides. There remain, however, accounts of exhaust-gas fatalities in modern vehicles, whether accidentally or by suicide. These deaths and also crashes from fatigue could potentially be prevented by in-cabin multi-gas sensors, these having been developed to the prototype stage. Helpline signage at an exhaust-gassing suicide “hotspot” had some success in reducing suicides. The evidence on method substitution and whether a reduction in MVEG suicides causes a reduction in total suicides is inconsistent.

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