1 / 28

Earth’s Changing Environment Lecture 2

Earth’s Changing Environment Lecture 2. Air Pollution. “Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts.” - Rachel Carlson. The Atmosphere. N 2 780900 ppm (78.09%) O 2 209400 ppm (20.94%) Argon 9300 ppm (0.93 %)

winola
Download Presentation

Earth’s Changing Environment Lecture 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Earth’s Changing EnvironmentLecture 2 Air Pollution

  2. “Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts.” - Rachel Carlson

  3. The Atmosphere • N2 780900 ppm (78.09%) • O2 209400 ppm (20.94%) • Argon 9300 ppm (0.93 %) • CO2 372 ppm (0.037%) • Everything else is less than 0.003 % or 30 ppm

  4. Layers of the Atmosphere • Stratosphere begins at about 10 miles above the surface. • Pressure drops with altitude. • So, less oxygen with altitude.

  5. Air Pollution – Sources • Most air pollution is emitted from fixed and mobile sources at ground level.

  6. Buoyant Force • The density of air is proportional to its Temperature. • Hot polluted air is less dense than the cooler air around it. • So, hot polluted air will rise, expand, cool, and disperse

  7. Temperature vs. Altitude • Hot air released at ground level will loose temperature as it rises and expands. The rate at which its temperature drops is the adiabatic lapse rate (ALR) and equals 3.5F per 1000 feet. • The environmental lapse rate (ELR) is typically equal to the ALR.

  8. Unstable Air • If the ELR > ALR, then hot polluted air will rise and disperse.

  9. Temperature Inversion • If the there is a temperature inversion (a warm layer above the cool surface layer), the air will not rise. • This may lead to a severe pollution episode. • Temperature inversions are frequently caused by radiative cooling of the ground at night.

  10. Subsidence Inversion • Descending air compresses and warms, creating an inversion layer

  11. Global Air Circulation The combination of air density, uneven solar heating, and the Earth’s rotation explains global air circulation and climate zones.

  12. Hadley Cells

  13. Pollutants • Gases – CO, SOx, O3, NOx, and VOC • SPM (suspended particulate matter) – particulates and aerosols

  14. Primary vs. Secondary

  15. CO • Primarily due to auto emissions.

  16. SO2 • Primarily from power plants: coal and oil.

  17. VOC • In rural areas, natural sources dominate. • In urban areas, transportation dominates.

  18. NOx • Primarily from power plants and transportation • Emitted as NO and oxidized to NO2

  19. Particulates • From Industry, power plants, and transportation

  20. Photochemical Smog • Main harmful ingredient in smog is ozone. • Ozone is formed when UV radiation, high temperatures, Nitrogen oxides, and VOCs combine. • Automobiles are the main problem.

  21. Ozone • Ozone is primarily a summer problem in the US. • Higher temperatures and higher ozone levels are need to drive the reactions. • VOCs have many sources. • NOx is primarily from cars.

  22. Acid Rain • Acid rain is formed from SO2 and NO2 pollution.

  23. Acid Rain • Sulfuric acid (H2SO4) and nitric (HNO3) acid are formed and precipitated on vegetation in lakes and streams.

  24. pH • Normal rainwater is slightly acid because of carbonic acid (H2CO3) and nitric (HNO3). pH =5.6 • pH values between 4.0 and 4.5 are common in NE, Canada, northern Europe

  25. Health Effects: Outdoor Air Pollution • Kills 200,000 - 570,000 annually globally. • Kills 20,000 people annually in US. • Particulates and ozone are the biggest problem • Major sources are coal-burning power plants and vehicle emissions

  26. Worse Air Pollution Disaster • London, England, 1952 • From December 5 to 8, 1952 • The meteorological conditions were ideal for a pollution. Anti-cyclonic or high pressure weather with stagnating continental polar air masses trapped under subsidence inversions produced a shallow mixing layer with an almost complete absence of vertical and horizontal air motion. • Fireplaces and industries supplied the hygroscopic condensation nuclei into the air to form dense fog. • Deaths from bronchitis increased by a factor of 10, influenza by 7, pneumonia by 5, tuberculosis by 4.5, other respiratory diseases by 6, heart diseases by 3 and lung cancer by 2. • 4,000 Londoners perished.

  27. Health Effects: Indoor Air Pollution - Global • Kills 2.8 million annual globally • In developing countries, burning wood and other materials for heat and cooking is the major source.

  28. Health Effects:Indoor Air Pollution - US • Kills 100,000 people annually in US. • Cigarette smoke, formaldehyde, and radon-222 are primary indoor pollutants.

More Related