Air pollutants are broadly classified into primary and secondary pollutants based on their… — State PSC Exam

Air pollutants are broadly classified into primary and secondary pollutants based on their origin. Which of the following is classified as a secondary air pollutant?

Ground-level Ozone ( $O_3$ )Answer
B
Sulfur dioxide ( $SO_2$ )
C
Carbon monoxide ( $CO$ )
D
Particulate matter ( $PM_{2.5}$ )

Answer

Ground-level Ozone (

O_3

) is a secondary air pollutant because it forms in the atmosphere through chemical reactions between primary pollutants in the presence of sunlight.

Ground-level ozone (

O_3

) is formed when primary air pollutants such as nitrogen oxides (

NO_x

) and volatile organic compounds (VOCs) react chemically in the atmosphere under sunlight, defining it as a secondary air pollutant.

Step-by-Step Solution

Identify the definition of primary vs secondary pollutants

Primary pollutants are emitted directly from sources, while secondary pollutants are formed through atmospheric reactions between primary pollutants.

Classification depends on whether the substance is emitted directly or produced chemically post-emission.

Evaluate the origin of Ground-level Ozone

Ground-level Ozone (

O_3

) is formed via photochemical reactions involving

NO_x

and VOCs triggered by solar radiation.

No direct emission source releases ground-level ozone as a primary pollutant.

Key Concept

Classification of Air Pollutants (Primary vs. Secondary Pollutants)

Estimated Time:45s

Question

Answer

Step-by-Step Solution

Key Concept

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