Exhaust gas that they produce smaller quantities of toxic pollutants (e.g. oxides of nitrogen) than petrol and diesel engines of the same power. They produce larger quantities of carbon dioxide but less carbon monoxide due to more efficient combustion. Researchers from the University of California, Los Angeles School of Public Health say preliminary results of their statistical study of children listed in the California Cancer Registry born between 1998 and 2007 found that traffic pollution may be associated with a 5% to 15% increase in the likelihood of some cancers. A World Health Organization study found that diesel fumes cause an increase
Extermination camp the German civil populace. During the initial phase of the Final Solution, gas vans producing poisonous exhaust fumes were developed in the occupied Soviet Union (USSR) and at the Chełmno extermination camp in occupied Poland, before being used elsewhere. The killing method was based on experience gained by the SS during the secretive "Aktion T4" programme of involuntary euthanasia. There were two types of death chambers operating during the Holocaust. Unlike at Auschwitz, where the cyanide-based Zyklon-B was used to exterminate trainloads of prisoners under the guise of "relocation", the camps at Treblinka, Bełżec, and Sobibór, built during Operation Reinhard