This case is notable because after 8 to10 h of breathing exhaust fumes in a closed garage, the patient’s HbCO level was only 4.8%. The half-life of CO at 100% O2 at sea level is 80 min. Using extrapolation, this patient’s HbCO level at the scene would have been < 10%, well below the toxic level of 20%. The automobile in this case was a 1995 model equipped with a catalytic converter.
Closed-environment exposure to MVEGE from automobiles not equipped with catalytic converters can result in death within 30 min. The introduction of catalytic converters beginning with 1975 new-car models dropped CO emission rates to 6.00 g/min. By 1989, the average new-car CO emission at idling was 0.22 g/min. The catalytic conversion process removes CO, hydrocarbons, and nitrogen oxide; the resultant emission is a more desirable mixture of nitrogen, CO2, and water. Contemporary three-way catalytic converters eliminate > 99% of CO emissions.
Och utvecklingen gällande motorer har som tidigare nämnt fortsatt i nämnd riktning i anmärkningsvärd takt. Det bör dock noteras att motorer fortfarande förbrukar syre (vilket även kan orsaka att motorn stannar) - under särskilda omständigheter går det alltså fortfarande att uppnå skadlig miljö, så det kan vara en god idé att ha en kolmonoxidmätare tillgänglig ifall man tillbringar mycket tid kring motorer i drift.
Cartman har sammanfattat tendensen väl (felstavningen i originalet):
[Cartman comes into class after saying the previous day that he was going to kill himself]
Kyle Broflovski: What happened, Cartman? I thought you were going to kill yourself.
Eric Cartman: I tried. I went to sleep in my mom's car in the garage with the engine running.
Kyle Broflovski: And you didn't die?
Eric Cartman: [sighes] Freaking hybrids, man... they just don't do the trick anymore.
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