Question

Which is/are the secondary air pollutant(s)?

• A. $O_3$
• B. $HNO_3$
• C. $CO_2$
• D. $H_2SO_4$

Answer 1

The Correct Option is A, B, D

Step 1: Differentiate primary and secondary air pollutants. 

Primary pollutants: Directly emitted into the atmosphere from sources such as vehicles, industries, or natural processes. Examples include \( \text{CO}_2 \), \( \text{SO}_2 \), and \( \text{NO}_x \). 
Secondary pollutants: Formed by the chemical reactions of primary pollutants in the atmosphere. Examples include \( \text{O}_3 \), \( \text{HNO}_3 \), and \( \text{H}_2\text{SO}_4 \). 

Step 2: Analyze the options. \( \text{O}_3 \): A secondary pollutant formed by the photochemical reaction of \( \text{NO}_x \) and volatile organic compounds (VOCs). \( \text{HNO}_3 \): A secondary pollutant formed by the reaction of \( \text{NO}_x \) with water vapor. \( \text{CO}_2 \): A primary pollutant directly emitted from combustion processes. \( \text{H}_2\text{SO}_4 \): A secondary pollutant formed by the oxidation of \( \text{SO}_2 \) in the atmosphere.