Question

Automobile exhaust gas that causes major respiratory problems is Automobile exhaust gas that causes major respiratory problems is
A. CO
B. $CH_{4}$
C. $NO_{2}$
D.Chlorine

Answer 1

Any undesirable change in physical, chemical or biological characteristics of air, water and land that may or will adversely affect human life, industrial process, living conditions and cultural assets is called pollution. So air pollution is the occurrence of foreign particles or gases in the atmosphere which are harmful to man, plants and animals.

Complete answer: Automobiles are the largest sources of air pollution in the metro cities
Carbon monoxide accounts for about 50% of total air pollution. It is formed by incomplete combustion of carbon fuels in automobiles, industries, vehicles, kitchens etc. Automobiles contribute to about 50% of CO emission. Over 15 million tons of carbon monoxide are added to the environment every year.
Carbon monoxide readily binds the hemoglobin so decreasing its oxygen carrying capacity leads to hypoxia in body tissues. It causes headache, muscular weakness, nausea, exhaustion, psychomotor disturbances, etc. When 50% of hemoglobin has been transformed into carboxyhemoglobin then death occurs due to carbon monoxide poisoning.
Nitrous oxides decrease gaseous exchange in blood and hinder the functioning of lung nitrogen dioxide inhalation causing eye irritation, lung edema, and blood congestion. It is also a mutagen.
Proper maintenance of automobiles along with the use of lead-free petrol or diesel can reduce the pollutants they emit. Catalytic converters use expensive metals namely rhodium and platinum-palladium as the catalysts that are fitted into automobiles for reducing emissions of poisonous gases.
The unburnt hydrocarbons are converted into carbon dioxide and water and carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively by the catalytic converters.
So, the correct answer is “Option A”.

Note: Methane is produced naturally from burning of vegetation and incomplete decomposition. It is a greenhouse gas. Chlorine is a chlorofluorocarbon. Both of these gases contribute to greenhouse effect and global warming.