Understanding Air Quality: Pollution Sources, Effects, and Improvement Strategies

1. The Atmosphere B2: Air Quality

2. Air Quality • Air Quality – the degree to which the ambient air is pollutant-free. • Pollutant – substance in the air, water, or soil that is harmful to living things • Air Quality Index (AQI) – a number used by government agencies to indicate the degree to which the air is polluted • As the level of pollution increases, the number increases. • Different countries have their own AQI scale which are currently notconsistent

3. Air Quality • United States – The Environmental Protection Agency (EPA) has developed their own AQI. • Divided into six categories of increasing health concern • The U.S. AQI is based on the 5 pollutants regulated by the CleanAirAct • Ground level ozone, • particulate matter, • carbon monoxide, • sulfur dioxide, • and nitrogen dioxide

4. Air Quality • Most weather websites will report the AQI • Weather Channel Report • AQI Report for July 29th

5. Sources of Pollution • Sources – Pollution can occur naturally and as a result of human activities • Natural Sources – many natural processes add particles to the atmosphere • Forest fires, soil erosion, and dust storms release a great deal of particles into the air • The wind carries particles of mold and pollen • Volcanoes erupt with great clouds of ash and poisonous gases

6. Sources of Pollution • Human Sources – Activities human engage in that increases pollutants • Farming and Construction – Can send soil and dust into the air • Fossil fuels – The majority of air pollution by humans is the result of burning fossilfuels • Fossil fuels are burned in cars, homes, factories, and power plants • Producessoot (particles and hydrocarbons), carbon monoxide, nitrogen oxide, and sulfur dioxide • Causes smog and acid rain

7. Smog and Acid Rain • Smog – Combination of the words ‘smoke’ and ‘fog’ • Soot Smog – Forms when particles in coal smoke combine with water droplets in humid air • First noted 100 years ago in London, England where factories and most homes were heated with coal • Air became filled with soot which combined with the fog to create a dark, dirty cloud that hung over the city • Today, they burn much less coal which has resulted in cleaner air

8. Smog and Acid Rain • Photochemical Smog – Formed by the action of sunlight on pollutants such as hydrocarbons and nitrogen oxides • These chemicals react to form a brownish mixture of ozone and other pollutants • This type of fog is typically found in large cities with lots of sun • However wind can disperse these pollutants for many miles around

9. Smog and Acid Rain • Acid Rain – Rain that is more acidic than normal rain (which is naturally slightly acidic) • Formation – Burning coal, which contains sulfur, produces sulfur oxide • Sulfur oxides combine with nitrogen oxides and the water in the air • The combination of the three forms nitric acid and sulfuric acid • Then rain, sleet, snow, and fog carry these two acids into trees and lakes

10. Smog and Acid Rain • Effects – Acid rain causes a lot of environmental damage that can affect entire ecosystems • Can make water so acidic that plants, amphibians, and fish can no longer survive in it. • Killstrees and forests, especially needle-leaf trees like pine and spruce • It can also damage the surfaces of buildings and statues

11. Effect of Pollution • Carbon Monoxide • Burning of fossil fuels • Reduced ability of blood to deliver oxygen to cells • Nitrogen Dioxide • Burning of fossil fuels • Breathing problems, lung damage • Chemical reaction of certain carbon compounds • Breathing problems, asthma, eye irritation • Ozone • Particles (dust, smoke, soot) • Burning of wood, fossil fuels, and volcanic eruptions • Respiratory illnesses, nose and throat irritation and infections • Sulfur Dioxide • Burning of fossil fuels & volcanic eruptions • Breathing problems, lung damage

12. Improving Air Quality • Quality – In the U.S., federal and state governments have passed laws and regulations to reduce air pollution • In general, air quality has improved over the past 30 years • Newer cars cause less pollution than older ones • Recently-built power plants are less polluting • However, there are more cars and power plants than ever before • Many American cities are still polluted

13. Improving Air Quality • Voluntary measures such as car pooling, using public transportation, and energy saving appliances, window, and heating all help reduce pollutants • Some people want more regulations • Others argue it is expensive and should not be mandated

14. In Closing • What do you think we should do to reduce air pollution?