1. Chapter 12, Section 1: What Causes Air Pollution? Standards: SEV3a
Air & Air Pollution
Chapter 12, Section 1: What Causes Air Pollution?
Standards: SEV3a

2. What is the normal composition of air?
78% Nitrogen
21% oxygen
1% various other gases like
Argon
Carbon dioxide
Water vapor

3. What is air pollution?
Any harmful substance that builds up in the air to unhealthy levels.
Can be natural: pollen, dust, gases from volcanoes
Mostly human caused: car exhaust, coal-fired power plants, industrial pollution, etc.

4. What is the difference between a primary and secondary pollutant?
Primary pollutant
Put directly into air by human activities
Ex: Sulfur dioxide released from burning fossil fuel.
Secondary pollutant
Primary pollutants react with other primary pollutants or water vapor to make a new substance
Ex: Sulfur dioxide mixes with water in atmosphere and causes acid rain.

5. What are the 5 primary air pollutants?
Carbon monoxide
Nitrogen oxides
Sulfur dioxides
Volatile Organic Compounds
Particulate Matter

6. 1. Carbon Monoxide (CO) Description: Primary Source: Effects:
Odorless, colorless
Poisonous
From incomplete combustion of fossil fuels
Primary Source:
Vehicles (cars, trucks, buses)
Industrial processes
Effects:
Blood can’t carry oxygen as well, feel sleepy & disoriented; can cause death

7. 2. Nitrogen Oxides (NOx) Description: Primary Source: Effects:
Can be yellowish gas
Forms under high temps
Primary Source:
Vehicles (cars, trucks, buses)
Power plants
Industrial boilers
Effects:
Brownish haze from smog comes from NOx
Some acid precipitation
Makes body vulnerable to respiratory disease & cancer

8. 3. Sulfur dioxides (SO2) Description: Primary Source: Effects:
Pungent smell
Primary Source:
Burning fossil fuels
Power plants
Refineries
Smelters
Volcanic activity
Effects:
Contributes to acid rain
Harm plants
Irritate respiratory system

9. 4. Volatile Organic Compounds (VOCs)
Description:
Organic chemicals
Vaporize readily
Form toxic fumes
Primary Source:
Vehicles (cars, trucks, buses)
Burning fossil fuels
Effects:
Contribute to smog formation
Harm plants
Linked to cancer

10. 5. Particulate Matter (PM)
Description:
Tiny pieces of liquid or solid matter
Primary Source:
Construction, agriculture, forestry, fires
Vehicles, power plants & Industrial processes
Effects:
Form clouds & reduce visibility
Small pieces can be inhaled & clog respiratory system
Linked to cancer
Corrode metal & erode buildings
Divided into:
Fine particulate matter (PM 2.5)- from burning fossil fuels; worst because can be inhaled deeper into lungs
Coarse particulate matter (PM10)- incinerators, mining, cement plants

11. How long have air pollution problems been around?
As early as 2000 years ago, people complained of “foul air”
Air pollution problems became worse around the Industrial Revolution of the 1800’s when fossils fuel usage increased and no standards existed for how much pollution could be emitted.
Weather History: The Great Smog of London

12. What are two main sources of air pollution?
Motor Vehicle Emissions
Industrial Air Pollution

13. What are Motor Vehicle Emissions?
Fumes & particulates produced from the burning of gasoline in vehicles
1/3 of air pollution comes from gasoline burned by vehicles.
Clean Air Act-
regulates vehicle emissions
Banned lead in gasoline- lead pollution has decreased by 90% in US.
Catalytic converters clean exhaust gas
EPA says vehicles today burn fuel 35% more efficiently and with 95 % fewer emissions (except CO2) than they did 30 years ago.

14. What are Zero-Emissions Vehicle (ZEV) Programs?
Established in CA, MA, ME, NY, & VT
Offer rebates, tax incentives, closer parking, use of special HOV type lanes for ZEVs
Types of ZEVs:
Electric cars- plug in to recharge
Hybrid cars- run on both gas and electric
Methanol fuel cell cars

15. What are Industrial Air Pollutants?
Any industry or power plant that burns fuel to produce energy
Power plants produce
2/3 of all SO2 emissions
1/3 of all NOx emissions
VOCs are common type
From dry cleaning fumes
Oil refineries
Chemical plants
Car repair shops

16. What are Industrial Air Pollutants?
Clean Air Act requires one of the following:
Scrubbers installed in smoke stacks to control air pollution
Gases move through spray of water that dissolves the pollutant
Electrostatic Precipitators
Use static electricity to attract particulates from burning of fossil fuels

17. What is smog?
Air pollution that hangs over urban areas and reduces visibility.
Car exhaust reacts with air & sunlight to make ground level ozone.
Ozone reacts with more car exhaust to make smog.
Smog in Beijing, China (~2min)

18. What is a Temperature Inversion?
Circulation keeps air pollution from reaching dangerous levels.
If a warm air mass traps a cool air mass it will trap pollution with it.
Usually common in cities surrounded on 3 sides by mountains.
Mountains trap the air.
Donora, PA (1948)- 18 people died when temperature inversion trapped SO2 & HF pollution being released from a local steel mill.

19. You should be able to…
Name 5 primary pollutants & give important sources for each.
Name the 2 major sources of air pollution in urban areas.
Describe the way in which smog forms.
Define the term temperature inversion. Explain how temperature inversion traps pollutants near Earth’s surface.