4D Air Pollution

4D Air Pollution : 4D Air Pollution

Introduction : Introduction 1. How does air pollution cause billions of dollars in damage each year? a. it corrodes buildings and machines b. stunts the growth of agricultural crops and weakens livestock c. causes or aggravates disease such as bronchitis, asthma, emphysema, and lung cancer

To Exist is to Pollute : To Exist is to Pollute 2. What is the difference between pollutants generated by nature and those generated by man? natures pollutants occur over such a wide area that we do not notice them, we generate it in very small areas 3. When does air pollution become a serious problem? when it overcomes nature’s ability to dispose of it and disperse it

Slide4 : 4. List the Primary Air Pollutants, their human source and their natural source CO2 combustion of wood and fossil fuels( 22,000tons per year) / biological decay, oceans, forest fires respiration (1,000,000) CO incomplete combustion (700) / forest fires and photochemical rxns (2100)

Slide5 : SO2 combustion of coal and oil, smelting of ores (212) / Volcanoes ( 20) CH4 combustion (160) / biological decay and termites (1050) NOx High Temp combustion (75 ) / lightning bacteria in the soil (180 ) NH3 sewage treatment and fertilizers(6) / biological decay (260) H2S petroleum refinery and sewage treatment (3) / volcanoes and biological decay (84)

Slide6 : 5. How are secondary air pollutants formed? Name some examples formed in the atmosphere by the chemical reactions of primary pollutants and the natural stuff that is in the air(SO2 + O2 --> SO3, SO3 + HOH --> H2SO4) 6. What are particulates? Name some examples solid particles that get into the air. (emissions from smoke stacks and car tail pipes)

Slide7 : 7. What are “Man Made Substances”? Name some examples? pollutants such as freon which are produced only by man

Do Making Decisions on Page 317 : Do Making Decisions on Page 317

Smog: the Spoiler of our Cities : Smog: the Spoiler of our Cities 8. What is air quality index? a number that describes the concentration of pollutants that are the major contributors of smog 9. How dangerous is smog? quite dangerous-in 1952, during one of the deadliest fogs in history, the death rate almost doubled in London

Slide10 : 10. The composition of smog depends on what? type of industrial activity and power generation in an area, climate, and geography 11. Why is the combustion of fossil fuels a particular problem when it comes to smog production? these things contain varying amounts of sulfur that convert to sulfur oxides

Slide11 : 12. In what way has the smog problem been alleviated in recent years? many governments have set limits on the quantity of sulfur that may be present in the fuels used

Photochemical Smog : Photochemical Smog 13. Why was LA smog, first noticed in the 1940’s, so puzzling to scientists? it has no significant industrial or heating activities 14. What do scientists believe cause smog? automobiles, sunshine, and the fact that it is surrounded on three sides with mountains

Photochemical Smog : Photochemical Smog 15. What is a temperature inversion? cool air mass is trapped beneath a less dense warm air mass, 16. Why are they so dangerous? pollutants can’t escape and their concentrations may rise

Photochemical Smog : Photochemical Smog 17. Why is LA smog called a photochemical smog? sunshine provides that energy to create the smog gases 18. What are the two major bad guys in smog? How do they form? sunshine reacts with the nitrogen monoxide which is then converted to nitrogen dioxide in the air. 2NO + O2 + sunshine --> 2NO2(orange brown gas) NO2 + sunshine --> 2NO + O O + O2 --> O3 (Ozone)

Photochemical Smog : Photochemical Smog 19. What do these bad guys do to people and things? ozone can crack rubber, corrode metals, and damage animal and plant tissue, NO2 decreases visibility and irritates the eyes and respiratory system

Pollution Control : Pollution Control 20. What are the 5 ways which we can use to control pollution? a. replace energy tech that produce air pollution(such as coal fired plants) with ones that do not(nuclear) b. making automobilies and and energy plants more energy efficient(getting more energy for smaller amounts of fuel)

Pollution Control : Pollution Control c. remove pollution causing substances before the fuel is burned d. combustion can be modified so that almost everything is “burned up” e. trap the pollutants after combustion

Pollution Control : Pollution Control 21. What is the biggest stumbling block to effective pollution control? Moolah-all these measures require a great deal of it

Do Chemquandary 3 : Do Chemquandary 3

Lab: Cleansing Air : Lab: Cleansing Air

Read Chemistry at Work on page 326 for quiz tomorrow : Read Chemistry at Work on page 326 for quiz tomorrow

Controlling Auto Emissions of Pollutants : Controlling Auto Emissions of Pollutants 22. How were automobile emissions cleaned up during the 70’s? by modifying the air-fuel ratio, adjusting spark timing, and installing exhaust gas re-circulation systems 23. What was developed in order to clean up these emissions? catalytic converters

Controlling Auto Emissions of Pollutants : Controlling Auto Emissions of Pollutants 24. What does a catalytic converter do? reaction chamber attached to the exhaust pipe that helps to convert nitrogen and hydrocarbons to carbon dioxide and water 2NO(g) + 2CO(g) -->(with catalyst) N2(g) + 2CO2(g) 2NO(g) + H2(g) -->(with catalyst) N2(g) + 2H2O(g)

Controlling Auto Emissions of Pollutants : Controlling Auto Emissions of Pollutants 25. What is a catalyst? molecules like enzymes that speed up reactions by making it easier for the reactants to do their thing. 26. How do catalysts work? They lower the activation energy hill for the reaction

Controlling Industrial Emission of Particulates : Controlling Industrial Emission of Particulates 27. Who generates 60% of the particulate matter in the US? power plants and smelters(metal making factories) 28. Name and describe 4 ways in which Industry has been “cleaning up its act”? a. Electrostatic precipitation(kind of like electrostatic filters at home) solids particulates pass through a strong electric field making them charged. The particles then collect on a plate that contains the opposite charge

Controlling Industrial Emission of Particulates : Controlling Industrial Emission of Particulates b. Mechanical filtering: (like a bag in a vacuum cleaner) huge filters trap up to 99% of the dust c. Cyclone collection: products pass through a tight circular spiral chamber, heavier particles are thrown against the walls and collect at the bottom, not very effective

Controlling Industrial Emission of Particulates : Controlling Industrial Emission of Particulates d. Scrubbing-gases containing sulfur and passed through water containing chemicals that will react with the sulfur and settle out as a solid

Do Chemquandary 4 : Do Chemquandary 4

Ozone and CFC’s: A Success Story : Ozone and CFC’s: A Success Story 29. Why is too much UV radiation bad for us? Can break the covalent bonds that hold DNA Causes sunburn and even cancer 30. What protects life on earth from too much UV? Ozone layer

Slide30 : 31. What would a 1% decrease in stratospheric ozone mean to us, according to the National Research Council? 2-5% increase in skin cancer Lower yields of food crops Increase in eye cataracts Damage to some water plants

Slide31 : 32. Use equations to explain how the ozone works? 33. What are the major culprits of the depletion of the ozone? CFC’s-chloro fluoro carbons, the Freons

Slide32 : 34. What have CFC’s been used for? Propellants in aerosol cans Cooling fluids for Fridges and air conditioners Cleaning solvents for computer chips

Slide33 : 35. Use equations to describe how CFC’s affect ozone? 36. When did researchers began to suspect that the ozone layer was being affected by CFC’s? In the early 70’s

Slide34 : 37. How has this threat been dealt with? By international accord the production of CFC’s has been phased out Replacements have been introduced 38. What is wrong with the replacement: Hydrochlorofluorcarbons(HCFC)? It may contributing to the Greenhouse effect gases

Slide35 : 39. What has been our response to this? Development of HFC’s- a group of molecule similar to CFC’s but not containing chlorine which is the major problem