On 30th October 2006, a software company owner traveled with his two employees in his air-conditioned Hyundai car in Chennai. On the way there was a heavy rain and due to heavy water on the roads he could not drive further and he stopped the car and waited for the road to be cleared of water. But due to suffocation inside the closed air-conditioned car all the three persons inside the car died. From their “Postmortem Report”, it was found that they lost their lives by the inhalation of Carbon Monoxide (CO).

A Hyundai spokesman told that it was impossible for an air conditioner in Hyundai car to emit carbon monoxide inside the car, as the engine is the one, which emits CO, but the exhaust pipe is away from the passenger area and nobody could die due to air conditioner's CO emisssions in the modern automobiles.

In December 2007, at Trivandrum, in a closed air-conditioned Maruthi Zen car, the dead body of a girl was found and the dead bodies of two young men were found inside the garage near the car. The two men and the girl had been inside the closed air-conditioned car, parked inside the closed garage, celebrating some sort of a party with liquors. Due to suffocation possibly, the men tried to rush out of the car but died. The cause of death of the three persons was found to be “Inhalation of Carbon Monoxide”.

Petrol engines emit considerable amounts of Carbon Monoxide (CO) which is often a product of ineffective combustion, often up to 25 per cent of the exhausted gases. Most modern day vehicles, such as the Maruti Zen, are equipped with catalytic converters that minimise CO emission.

In both the incidents the cars had been idling for a long time, one inside a closed garage and the engine got deprived of sufficient levels of oxygen needed for proper combustion and emission of more Carbon Monoxide should have been there. Inefficient combustion and lack of proper ventilation must have caused lethal levels of CO to accumulate in the garage. The air-conditioning system had sucked much of the deadly gas back into car's closed cabin space, causing the deaths of the occupants, the experts said.

The above two incidents are in some ways similar, and the possible reason for the death should be “Inhalation of Carbon Monoxide”, according to experts, due to prolonged use of aircondition without proper ventilation. It is obvious that prolonged running of air-condition in cars will lead to emission of more of CO.

Readings on Carbon Monoxide Emissions:-
http://www.carbonmonoxidekills.com/carbon_monoxide_emissions.htm
http://www.carbon-monoxide-poisoning.com/co-emissions.html