1. Air Pollution Anti-Lecture
Targets:
Describe the sources of air pollution and the effects of different pollutants in the air.
Explain how environmental changes can increase or decrease air pollution in an area.

2. What is air pollution?
What causes what we see?

3. Major Classes of Pollutants found in Ambient Air
Carbon oxides
Sulfur oxides
Nitrogen oxides
VOCs
SPM
Radioactive substances
HAPs

4. Major Outdoor Air Pollutants - EPA
CO2
NO2
SO2
SPM
Ozone
Lead

5. Primary and Secondary Pollutants
Primary: emitted during into troposphere in a potentially harmful form
Secondary: formed when primary pollutants react with one another

6. Stationary vs. Mobile Sources
Stationary – power plants and factories
Mobile – motor vehicles
Remember the electric vehicle FRQ!

7. Photochemical Smog
VOCs + SOx + heat + sunlight (UV radiation)  ground level O3 + other photochemical oxidants + aldehydes + other secondary air pollutants
Also known as the red-air smog
Occurs in areas with sunny, warm and wet climates

8. Photochemical Smog - Formation
Process starts inside automobile engines and boilers of coal-burning power and industrial plants
Due to the high temperatures in there, S and O in the air react to produce sulfur dioxide.
In the atmosphere, some of the SO2 converts to SO3 which causes the red haze hanging over cities

9. Photochemical Smog – Formation con’t
Some of the SO2 reacts with hydrocarbons to produce photochemical smog – ozone, nitric acid, aldehydes, PANs, and other secondary pollutants.
When days are hotter, there are lower levels of ozone .

10. Industrial Smog
Consists mostly of NO2, aerosols containing nitric acid, and SPMs
Also known as brown-air smog due to SPM of salts and soot
Found predominately in developed countries with heavy industrialized areas

11. Industrial Smog - Formation
When burned, C in coal and oil is converted to CO2 and CO. Some also ends up as soot.
N in coal and oil reacts with oxygen to produce NO2
Ammonium sulfate forms when ammonia reacts with suspended droplets of sulfuric acid

12. Factors that Reduce Air Pollution
Rain and snow
Salty sea spray
Mountains and hills

13. Factors that Increase Air Pollution
Winds
Urban buildings
High temperatures
Grasshopper effect

14. What is a temperature inversion and how does it occur?

15. Temperature Inversions
Layer of cool air lies on top of warm air trapping it near the ground.
Pollutants concentrate in the stagnant warmer air and can’t disperse

16. Areas Susceptible to Temperature Inversions
Towns and cities located in a valley surrounded by mountains where they experience cold and cloudy weather
Mountains and clouds block winter sun
Cities with several million people and motor vehicles