Gas chamber carbon monoxide as the lethal agent. Sometimes a box filled with anesthetic gas is used to anesthetize small animals for surgery or euthanasia. Gas chamber A gas chamber is an apparatus for killing humans or other animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. The most commonly used poisonous agent is hydrogen cyanide; carbon dioxide and carbon monoxide have also been used. Gas chambers were used as a method of execution for condemned prisoners in the United States beginning in the 1920s and continue to be a legal execution method in
Diesel exhaust U.S. 2010 emissions criteria, selective non-catalytic reduction (SNCR), and exhaust gas recirculation (EGR). Both are in the exhaust system of diesel engines, and are further designed to promote efficiency. Selective catalytic reduction (SCR) injects a reductant such as ammonia or urea — the latter aqueous, where it is known as diesel exhaust fluid, DEF) — into the exhaust of a diesel engine to convert nitrogen oxides (NO) into gaseous nitrogen and water. SNCR systems have been prototyped that reduce 90% of the NO in the exhaust system, with commercialized systems being somewhat lower. SCR systems do not necessarily need particulate