1. Particles in the Air

2. Key Particles in the Air Natural Human Factors Type of Particles Source KEY

3. Key Particles in the Air Natural Human Factors Soot (Carbon) Type of Particles Source KEY

4. Key Particles in the Air Natural Human Factors Soot (Carbon) Burning Wood or Coal Type of Particles Source KEY

5. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Burning Wood or Coal Type of Particles Source KEY

6. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Burning Wood or Coal Farming & Construction Type of Particles Source KEY

7. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Salt Burning Wood or Coal Farming & Construction Type of Particles Source KEY

8. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Type of Particles Source KEY

9. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Dust & Ash (Rock Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Type of Particles Source KEY

10. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Dust & Ash (Rock Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Volcanoes Type of Particles Source KEY

11. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Pollen & Mold Dust & Ash (Rock Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Volcanoes Type of Particles Source KEY

12. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Pollen & Mold Dust & Ash (Rock Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Volcanoes Plants and Fungi Type of Particles Source KEY

13. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Dust, Soil & Ash Pollen & Mold Dust & Ash (Rock Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Volcanoes Plants and Fungi Type of Particles Source KEY

14. Key Particles in the Air Natural Human Factors Soot (Carbon) Dirt (Soil Particles) Dust, Soil & Ash Pollen & Mold Dust & Ash (Rock Particles) Salt Burning Wood or Coal Farming & Construction Ocean Waves Volcanoes Plants and Fungi Forest Fires, Soil Erosion/Dust Storms Type of Particles Source KEY