8.3.2—Primary pollutant sources
- Syllabus
- First assessment 2026
- Objective
- 8.3.2
- Level
- HL
Classify the Source, Not the Emotion
A primary pollutant is directly active at emission; its source may be natural or anthropogenic.
| Source class | Required examples | Typical direct pollutant |
|---|---|---|
| Natural | forest fires, wind-blown dust, volcanic eruptions | smoke particles, dust, sulfur gases |
| Anthropogenic | burning for agricultural/forest clearance, fossil-fuel or biomass energy, construction and road dust | PM, CO, SO₂, NOx or dust |
Dust lifted by a storm is natural; dust from road building is anthropogenic. Both can be primary PM because they enter the atmosphere directly.
Natural does not mean harmless, and anthropogenic does not mean every later pollutant is emitted directly.