Calculation of mass content of water vapour in car exhaust gas

The paper presents the dependence between mass content of water vapour and combustion products that are formed in result of combustion of 1 kg of hydrocarbon and air excess coefficient at different negative ambient temperatures during 60 minutes of car engine operation. As a result, the authors have determined conditions of formation of the greatest amount of water vapour in engine exhaust gas.

Time trends in suicide rates by domestic gas or car exhaust gas inhalation in Japan, 1968–1994

AimsA reduction in the carbon monoxide content of domestic gas and car exhaust gas has been associated with a decrease in gassing suicides in many western countries. In Japan, a reduction in the carbon monoxide content of domestic gas supply began in the early 1970s, and carbon monoxide emissions standards of new passenger cars were significantly strengthened in 1978. However, little is known about the impact of detoxification of these gases on gassing-related suicides in Japan. Therefore, we examined the changing patterns of suicide due to domestic gas or car exhaust gas inhalation by gender and age in Japan between 1968 and 1994.MethodsSuicide mortality data were obtained from the Vital Statistics of Japan. In this study, age was divided into four groups: 15–24, 25–44, 45–64 and 65+ years. Method of suicide was divided into three groups: domestic gas, car exhaust gas and non-gases. We calculated method-specific age-standardised suicide rates by gender within each of the four age groups. We applied joinpoint regression to the data and quantified the observed changes.ResultsSuicide rates by domestic gas, regardless of gender and age, increased from 1968 to the mid-1970s and then decreased sharply. The proportion of all suicides accounted for by domestic gas was comparatively high in the mid-1970s among females aged 15–24 and 25–44 years, while for other gender-age-groups the proportion of domestic gas suicides remained small, even at the peak. For females aged 15–44 years, the decrease in domestic gas suicides appeared to cause a substantial decrease in overall suicides in this gender/age group. Car exhaust gas was a more common method for males, particularly those aged 25–64 years. Car exhaust gas suicide rates for males aged 25–64 years peaked in the mid-1980s, followed by a sharp decrease.ConclusionsA reduction in the carbon monoxide content of the domestic gas, which began in the early 1970s in Japan, was associated with a decrease in domestic gas suicides for both genders of all ages. Concerning females aged 15–44 years, a decrease in domestic gas suicides caused a substantial decrease in overall suicides in this gender/age group since the proportion of domestic gas suicides among all suicides combined was comparatively large. However, it remains uncertain whether the introduction of catalytic converters in the 1970s in Japan resulted in a reduction of suicides from car exhaust gas inhalation.

The New Forest Suicide Prevention Initiative (NFSPI)

A retrospective suicide study revealed that the Forestry Commission car parks in the New Forest in southern England were a previously unrecognized magnet for nonlocal suicides, attracting as high a proportion of “visitors” (35/43 in 1993-97) as among suicides who jumped from the cliffs at the infamous Beachy Head (39/48 in 1993-97). Over 95% of the car park suicides died from car exhaust gas poisoning. A multiagency initiative aimed to reduce the number of suicides in the 140 New Forest car parks where restricting access was impossible, and environmental issues paramount. Signs displaying the Samaritans' national telephone number were erected in the 26 car parks in which 50% of the car park suicides had occurred. Numbers, location, and residence of all car park deaths were monitored for 3 years. Corresponding changes in other forest registration districts were also monitored. During the 3-year intervention period the number of car park suicides fell significantly from 10/year, 1988-1997, to 3.3/year. The average annual total number of suicides in the New Forest registration district also decreased. No significant changes were found in comparable forest districts. The number of suicides in the New Forest car parks remained low during the 2 years following the evaluation.

Changes in rates of suicide by car exhaust asphyxiation in England and Wales

Background. Self-asphyxiation using car exhaust gas is a common method of suicide in England and Wales, particularly in young males. The introduction of catalytic converters has reduced the toxicity of car exhausts. The main aims of the study were: to seek evidence of a fall in car exhaust suicides in the general population and in age and gender groups; to relate any fall to changes in car exhaust systems, particularly since legislation on car exhaust emissions in 1993; and to examine rates of suicide by other methods for evidence of method substitution.Methods. Population study in England and Wales using national suicide statistics for 1987 to 1998.Results. There was a fall in suicide by car exhaust asphyxiation in all age and gender groups. This change was most marked after 1993. The overall population suicide rate (all methods) also fell but there was no overall change in suicides by young males or females. In these groups suicide by hanging increased.Conclusions. Legislation on catalytic converters appears to have contributed to a fall in car exhaust suicides. However, the effect on overall suicide rates in young people has been reduced by method substitution.

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

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.