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
Diesel exhaust decades, and a high share of sickness caused by automotive pollution. Exposure to diesel exhaust and diesel particulate matter (DPM) is an occupational hazard to truckers, railroad workers and occupants of residential homes in vicinity of a rail yard, and miners using diesel-powered equipment in underground mines. Adverse health effects have also been observed in the general population at ambient atmospheric particle concentrations well below the concentrations in occupational settings. In March 2012, U.S. government scientists showed that underground miners exposed to high levels of diesel fumes have a threefold increased risk for contracting lung cancer compared with those exposed