Aerosols and their effect on Global Climate

Context:  Role of Industrial Aerosols in contributing to Global Cooling. A new study reveals that inactive volcanoes contributed 66 percent of sulphate emissions, known to cool the planet, in the preindustrial era.

About Aerosols:

• Aerosols are defined as a combination of liquid or solid particles suspended in a gaseous or liquid environment.
• In the atmosphere, these particles are mainly situated in the low layers of the atmosphere (< 1.5 km) since aerosol sources are located on the terrestrial surface.
• However, certain aerosols can still be found in the stratosphere, especially volcanic aerosols ejected into the high altitude layers.
• Source of aerosols 
  • Natural sources – sea salt generated from breaking waves, mineral dust blown from the surface by wind, and volcanoes.
  • Anthropogenic aerosols – sulphate, nitrate, and carbonaceous aerosols, and are mainly from fossil fuel combustion sources.

Effects of aerosols:

• They affect the atmospheric chemical composition.
• They can reduce visibility.
• They have important impacts on air quality and human health (e.g. aerosols can cause damage to heart and lungs).

• They serve as nuclei for cloud droplets or ice crystals in ice clouds.

Source: DownToEarth   

Previous Year Questions

Q.1) Among the following crops, which one is the most important anthropogenic source of both methane and nitrous oxide ?

1. Cotton
2. Rice
3. Sugarcane
4. Wheat

Q.2) Consider the following:

1. Carbon monoxide
2. Nitrogen oxide
3. Ozone
4. Sulphur dioxide

Excess of which of the above in the environment is/are cause(s) of acid rain? (2022)

1. 1, 2 and 3
2. 2 and 4 only
3. 4 only
4. 1, 3 and 4