Understanding Air Pollution: Causes, Effects, and Sources

1. Agenda 4/7 • Unit Test A: 4/11 • Last Day to Reassess: 5/2 • Warm-Up: Which activity from your daily life creates the most air pollution? • 12.1 Notes • Air Pollution Reading/Discussion

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

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

4. 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.

5. 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.

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

7. 1. Carbon Monoxide (CO) • Description: • 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

8. 2. Nitrogen Oxides (NOx) • Description: • 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

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

10. 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

11. 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

12. 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 1952- London

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

14. 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.

15. 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

16. 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

17. 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

18. 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)

19. 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.

20. 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.