(a) Catalytic Converter : Catalytic converter are fitted into automobiles for reducing emission of poisonous gases. They have expensive metals, platinum palladium and rhodium as the catalysts. As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide (CO2) and water and carbon monoxide (CO) and nitric oxide are changed into carbon dioxide and nitrogen gas, respectively. However, automobiles equipped with catalytic converter should always use unleaded petrol because lead present in petrol, inactivates the catalyst.
(b) Ultraviolet-B : Ultraviolet B (UV-B) radiations are of larger wavelength and cannot be absorbed by Earth's atmosphere. These rays are highly injurious to living organisms. They damage DNA and may cause mutation. It causes aging of skin, damage to skin cells and various types of skin cancers. UV-B are very dangerous for human eyes because cornea of human eye absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness cataract, etc. or may permanently damage it.