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.
Match the following: Plastic Types and Applications
| Code | Plastic Type | Common Applications |
|---|---|---|
| P | High-density polyethylene (HDPE) | (iv) Geomembrane for landfill liner |
| Q | Low-density polyethylene (LDPE) | (i) Garbage bags, bubble packaging |
| R | Polyethylene terephthalate (PET) | (iii) Water bottles |
| S | Polystyrene (PS) | (ii) Pharmaceutical bottles, Styrofoam cups |