What cars put out higher levels of carbon monoxide?

If the cold start happens when the vehicle is in a (typically unventilated) residential garage, very high levels of CO can accumulate inside the garage --in the range of 100s of ppm (even with the garage door wide). read more

Not unless your car is on fire, or you build a fire inside the car, so long as the engine is off. People occasionally die of CO poisoning in houses due to running oil, gas, wood, or charcoal burning stoves without adequate ventilation. read more

In modern cars and trucks, the levels of carbon monoxide produced by the engine are much higher than the levels that are actually released to the atmosphere. This reduction is accomplished through emissions controls that were introduced in the 1970s and continuously refined, so classic cars still put out a lot more carbon monoxide than any vehicle sold today. read more