Question

Name two different types of smog. Explain briefly how they are formed?

Answer 1

Hint: The polluted air in the atmosphere is termed as smog. The word smog is the composition of two words that are smoke and fog and it is generally used to describe the polluted air which originates from automotive or chemical industries.

Complete answer:
When the gaseous pollutants are released by the industries in the atmosphere, these pollutants burn in the presence of sunlight and air-borne particles or ground level ozone is formed. It appears like fog and spreads around like smoke. Thus, it is usually termed as smog.
The two types of smog are as follows:
Sulfurous smog: It is also known as London smog. It is formed when oxides of sulfur are present in high concentration in the air. The major cause of formation of sulfurous smog is the use of sulfur bearing fossil fuels, specifically coal. This type of smog is easily aggravated by moisture and the matter is dispersed in the air in high concentration.
Photochemical smog: It is also known as Los Angeles smog. It mostly occurs in the area which has a large number of automobiles. This type of smog originates when the vapors of nitrogen oxide and hydrocarbons are released by automobiles and they react in the presence of sunlight to form ground level toxic ozone gas. This type of smog results in the brownish color of the atmosphere and is the major reason for respiratory diseases in humans.

Note:
It is important to note that ozone gas is one of the greenhouse gases and increasing the ground level of ozone will surely contribute to an increase in global warming. If the surface level ozone concentrations exceed 70 parts per billion for more than eight hours, then it is considered to be a highly toxic and unhealthy environment.