ABSTRACT
It was shown in the previous chapter that the increase of cars in the United States following World War II was accompanied by an increase in suicides by car exhausts. A further natural experiment relating to the availability of this method for suicide is provided by the introduction of exhaust emission controls in the United States. These controls were intended to reduce the level of air pollution by requiring new vehicles to be fitted with devices to remove, or greatly reduce, the toxic agents in exhaust gases, including hydrocarbons, nitrogen oxides, and carbon monoxide. It is the latter gas which is fatal in sufficiently high concentrations in a confined space, such as the passenger compartment of a car or a closed garage.
