Converters are mounted close to automobile engines and convert over 95% of hydrocarbons, carbon monoxide (CO) and nitrogen oxides into much less harmful gases.Since the first converters were introduced in the United States in 1974, it can be assumed that up till now more than 12 billion tons of exhaust gases have been filtered and rendered less harmful. More than 96% of automobiles built today are equipped with converters. According to the international association of vehicle manufacturers (OICA), 60 million cars are manufactured every year, and this number is bound to grow. With the stricter enforcement of emission regulations, the role played by auto catalytic converters will be increasingly important to meet these goals.
Converters may contain steel or ceramic monolith, but in both cases their internal structures are covered with a mixture of one or more platinum group metals (platinum, palladium and rhodium), which perform the important task of converting exhaust gases.