Add the emissions from exploration, transportation, refining and distribution of fuel, and this figure if 15 to 20 percent of world emissions. The average European car produces over 4 tonnes of carbon dioxide every year. Annually, about 120,000 tonnes of CFCs are used in new vehicles and in servicing air conditioners in older vehicles. In all, these uses account for 28 percent of global demand for CFC-12. Carbon monoxide interacts and uses up hydroxyl radical in the atmosphere.
Hydroxyl radical is the principle chemical for destroying methane.
Emissions of carbon monoxide increase global warming by removing a defense against the buildup of methane. Low level exposure over a long period most commonly effects the nervous system and blood. Can impair the mental abilities of children. 7 out of 10 children in Mexico city have had their development stunted by lead poisoning from cars. High benzene crudes sometimes added to fuel to improve the properties of premium unleaded gasoline.