What is the difference between primary and secondary pollutants?

Explanation

**Step-by-Step Solution:**

1. **Definition of Primary Pollutants:**
- Primary pollutants are substances that are directly emitted into the atmosphere from various sources. These pollutants are released in their original form and can include gases, particles, and other materials.

2. **Examples of Primary Pollutants:**
- Common examples of primary pollutants include carbon monoxide (CO) from vehicle emissions, sulfur dioxide (SO2) from industrial processes, and particulate matter (PM) from construction sites or wildfires.

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