Exhaust gas gas is undesirable, noxious, or toxic substances, such as carbon monoxide (CO) from incomplete combustion, hydrocarbons (properly indicated as CH, but typically shown simply as "HC" on emissions-test slips) from unburnt fuel, nitrogen oxides (NO) from excessive combustion temperatures, and particulate matter (mostly soot). Exhaust gas temperature (EGT) is important to the functioning of the catalytic converter of an internal combustion engine. It may be measured by an exhaust gas temperature gauge. EGT is also a measure of engine health in gas-turbine engines (see below). During the first two minutes after starting the engine of a car that has not
Multistorey car park term open parking garage to refer to a structure designed for car storage that has openings along at least 40% of the perimeter, as opposed to an enclosed parking garage that requires mechanical ventilation. Natural or mechanical ventilation provides fresh air flow to disperse car exhaust in normal conditions, or hot gas and smoke in case of fire. Typically car park experts describe the number of car park floors in terms of "G+x". G stands for ground and x for the number of floors above ground. For example, G+5 is a multi-story car park structure with a ground floor and