Consider the following statements regarding Dust Particles: 1. They are generally concentrated in the upper layers of the atmosphere. 2. Convectional air currents may transport them to great heights. 3. They are found in higher concentrations in equatorial regions due to wet winds. Which of the statements given above is/are correct?

The correct option is 2 only Explanation Dust particles, also known as aerosols, are solid particles suspended in the atmosphere. They originate from sources such as sea salts, fine soil, smoke-soot, ash, pollen, and disintegrated meteors. Their distribution varies significantly based on altitude, latitude, and weather conditions. Statement-wise Analysis: - Statement 1 is Incorrect: Although dust particles originate at the surface, strong convectional air currents can transport fine particulates to great heights. This vertical movement allows dust to act as hygroscopic nuclei for cloud formation at various altitudes. - Statement 2 is Correct: Dust particles are generally concentrated in the lower layers of the atmosphere. Since they are heavier than atmospheric gases and originate from the Earth's surface, gravity restricts the majority of these particles to the troposphere near the ground. - Statement 3 is Incorrect: Higher concentrations of dust particles are found in subtropical and temperate regions due to dry winds. In contrast, equatorial regions have lower concentrations because frequent rainfall and high humidity wash out these particles from the atmosphere. Key Takeaway: Dust particles are most abundant in the lower atmosphere of dry, subtropical regions. They are scarce in equatorial regions due to the cleansing effect of heavy rainfall.

NCERT Class 11 Geography — Chapter 1: Composition and Structure of Atmosphere

mcqmedium

Consider the following statements regarding Dust Particles:

They are generally concentrated in the upper layers of the atmosphere.
Convectional air currents may transport them to great heights.
They are found in higher concentrations in equatorial regions due to wet winds.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A2 only
B1 only
C1, 2 and 3
D1 and 3 only

Did you get this right?

Solution

The correct option is

2 only

Explanation

Dust particles, also known as aerosols, are solid particles suspended in the atmosphere. They originate from sources such as sea salts, fine soil, smoke-soot, ash, pollen, and disintegrated meteors. Their distribution varies significantly based on altitude, latitude, and weather conditions.

Statement-wise Analysis:

Statement 1 is Incorrect: Although dust particles originate at the surface, strong convectional air currents can transport fine particulates to great heights. This vertical movement allows dust to act as hygroscopic nuclei for cloud formation at various altitudes.
Statement 2 is Correct: Dust particles are generally concentrated in the lower layers of the atmosphere. Since they are heavier than atmospheric gases and originate from the Earth's surface, gravity restricts the majority of these particles to the troposphere near the ground.
Statement 3 is Incorrect: Higher concentrations of dust particles are found in subtropical and temperate regions due to dry winds. In contrast, equatorial regions have lower concentrations because frequent rainfall and high humidity wash out these particles from the atmosphere.

Key Takeaway:
Dust particles are most abundant in the lower atmosphere of dry, subtropical regions. They are scarce in equatorial regions due to the cleansing effect of heavy rainfall.

Your note

More from Chapter 1: Composition and Structure of Atmosphere

Consider the following statements regarding the composition of the atmosphere: 1. The proportion of gases remains constant up to the highest layers of the atmosphere. 2. Nitrogen is the most abundant gas in the atmosphere. 3. Nitrogen and Oxygen make up the bulk of the atmosphere. Which of the statements given above is/are correct?

easy

Which of the following is the main reason for the rising volume of carbon dioxide in the atmosphere?

easy

Consider the following statements regarding water vapour in the atmosphere: 1. It is a variable gas that increases with altitude. 2. It accounts for less than one % of the air by volume in the dry and cold polar regions. 3. It absorbs parts of the insolation from the sun and preserves the earth’s radiated heat. Which of the statements given above is/are correct?

medium

With reference to the composition of the atmosphere, consider the following statements: 1. Oxygen is found in substantial quantities at heights above 120 km from the earth's surface. 2. Carbon dioxide is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation. 3. Carbon dioxide and water vapour are found in uniform concentration up to the exosphere. Which of the statements given above is/are correct?

medium

Which one of the following is the most likely reason for the higher concentration of dust particles in subtropical and temperate regions compared to equatorial regions?

easy

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The correct option is

2 only

Explanation

Statement-wise Analysis:

Statement 1 is Incorrect: Although dust particles originate at the surface, strong convectional air currents can transport fine particulates to great heights. This vertical movement allows dust to act as hygroscopic nuclei for cloud formation at various altitudes.
Statement 2 is Correct: Dust particles are generally concentrated in the lower layers of the atmosphere. Since they are heavier than atmospheric gases and originate from the Earth's surface, gravity restricts the majority of these particles to the troposphere near the ground.
Statement 3 is Incorrect: Higher concentrations of dust particles are found in subtropical and temperate regions due to dry winds. In contrast, equatorial regions have lower concentrations because frequent rainfall and high humidity wash out these particles from the atmosphere.

Key Takeaway:
Dust particles are most abundant in the lower atmosphere of dry, subtropical regions. They are scarce in equatorial regions due to the cleansing effect of heavy rainfall.