1 / 66

How Humans Affect the Atmosphere: Air Pollution and its Impacts

How Humans Affect the Atmosphere: Air Pollution and its Impacts. Weather & Atmosphere – Meeting the Benchmarks CCISD, Hancock, MI Feb 15, 2002 Richard E. Honrath Dept. of Civil & Environmental Engineering Michigan Technological University. The major air pollutants. Carbon monoxide (CO)

daniel_millan
Download Presentation

How Humans Affect the Atmosphere: Air Pollution and its Impacts

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. How Humans Affect the Atmosphere: Air Pollution and its Impacts Weather & Atmosphere – Meeting the BenchmarksCCISD, Hancock, MIFeb 15, 2002Richard E. HonrathDept. of Civil & Environmental EngineeringMichigan Technological University

  2. The major air pollutants Carbon monoxide (CO) Nitrogen oxides (NOx) Ozone (O3) Particulate matter (PM-10, PM-2.5) Sulfur dioxide (SO2) Lead (Pb) Greenhouse gases (CO2 and others)

  3. Carbon Monoxide • Impacts: Blood oxygen levels Hb + O2 <-> HbO2 K1 = Equilibrium constant Hb + CO <-> HbCO K2 = 210 x K1 • Headaches, alertness, death • Sources: Vehicles (plus others) Source: Ref. (1)

  4. Carbon Monoxide • CO levels are improving, but still a problem in many colder urban areas. Source: Ref. (1)

  5. Nitrogen Oxides • NOx = NO + NO2 • Impacts: Respiratory irritant (NO2) (but AQ standard seldom violated) • Leads to ozone formation • Leads to acidic deposition of HNO3

  6. Nitrogen Oxides • NOx = NO + NO2 • Impacts: Respiratory irritant (NO2) • Leads to ozone formation • Leads to acidic deposition of HNO3 • Sources: High-temperature combustion N2 + O2  2NO Source: Ref. (1)

  7. Ozone • Impacts: • Respiratory irritant • Plant damage (forest, crops) (FACE site) • Oxidizes C=C double bonds: rubber • Sources: • Produced in the atmosphere NOx + VOCs + sunlight -> NOx + O3

  8. Ozone A major urban and regional pollution problem Source: Ref. (1)

  9. Particulate Matter • Definitions: • PM10 = PM < 10 um • PM2.5 = PM < 2.5 um • Impacts: • Lung irritation • Visibility

  10. Particulate Matter • Impacts: • Lung irritation • Visibility • Sources: Depends on particle size Source: Ref. (1)

  11. Particulate Matter Impacts: Visibility at Shenandoah Nat’l Park Source: Ref. (2)

  12. Sulfur Dioxide • Impacts: • Eye and lung irritation (but seldom > standard) • Acidic deposition of H2SO4. • Damage to limestone and concrete. • Sources: S in fuel is emitted as SO2 Source: Ref. (1)

  13. Sulfur Dioxide Impacts: Acidic deposition of H2SO4. Pure water pH = 5.6 Source: Ref. (3)

  14. Lead • Impacts: Brain and kidney damage. • Sources: Leaded gasoline was dominant, but Pb is no longer in U.S. on-road gasoline Source: Ref. (1)

  15. Lead Impacts: Brain and kidney damage. Sources: Metals processing, battery mfr, etc Source: Ref. (1)

  16. Greenhouse Gases Impacts: Global climate change Gases: Sources: See : Ref. (4)

  17. The Greenhouse Effect What determines the average temperature of the earth?

  18. The Greenhouse Effect What determines the average temperature of the earth? 1. Source: Ref. (5)

  19. The Greenhouse Effect What determines the average temperature of the earth? 2.

  20. The Greenhouse Effect What determines the average temperature of the earth? 3.

  21. The Natural Greenhouse Effect • Average solar radiation in: 236 W per square m

  22. The Natural Greenhouse Effect • Average solar radiation in: 236 W per square m • Without the atmosphere, temperature would be: -2 F

  23. The Natural Greenhouse Effect • Average solar radiation in: 236 W per square m • Without the atmosphere, temperature would be: -2 F • Greenhouse effect of natural water and CO2: 148 W per square m (1 lightbulb every 2 feet) • Result: Average temperature = 57 F

  24. The Human Contribution Source: Ref. (6)

  25. The Human Contribution • Total effect until now: about 2.3 W / m2 (1 light bulb every 15 feet) • Predicted effect by 2050: Up to 7 W / m2 (1 light bulb every 9 feet)

  26. What happens ifwe add 3 to 7 W / m2to the earth’s atmosphere?

  27. Recent Trends in Temperature Source: Ref. (6)

  28. Expected Impacts:More precip, more energy in weather • More extreme weather events are predicted • On average, more precipitation, but region-by-region, some will be wetter, some drier.

  29. Long-term Impacts:Models predict changes in climate Two climate models predict Illinois climate in 2030 and 2090. Source: Ref. (7)

  30. CO2 Emissions by Nation Developing nations will soon be the largest CO2 producers, but most CO2 in the atmosphere today came from to industrialized nations Source: Ref. (8)

  31. Emissions by Sector CO2 Emissions by Nation Easiest mitigation measure = energy efficiency Household emissions See : Ref. (4)

  32. Particulate Activities • Light scattering • Particles most effectively scatter light of wavelength ~ particle diameter. • Uncontrolled car exhaust scatters blue light. • Atmospheric gases also scatter, blue more than red. • Large concentrations of particle mixtures scatter all colors  white haze

  33. Haze in Los Angeles Source: Ref. (9)

  34. See Ref. (10) • Sky Blue, Sunset Red • Start with jar of clean water. • Demonstrate no scattering: • Shine light beam through – cannot see it from the sides, color at exit is white. • Add milk a little at a time • Observe effect on scattering: beam becomes visible, color at exit reddens, color from sides becomes bluish. • View an object through the jar: • Starts visible, becomes invisible: Haze. Particulate Activities

  35. Sky Blue, Sunset Red Key points: • Why is the sky blue? • Why is the sunset red? • Why does the sunset get redder when there are fires or pollution? • Why are far-away objects invisible in smoggy places? Particulate Activities

  36. See Ref. (10) • Air Strips • Obtain samples of particles and observe using magnifying glasses or microscopes. • Discuss local particle sources. Notes - Will only be able to see larger particles, like plant materials, dusts, or major smokes - Best to do during fall when more large particulates are in the air. Particulate Activities

  37. Local Issues • Vehicle emissions • Sources of CO, CO2, particulates, NOx, VOCs • Strategies for reducing emissions • Fuel economy (all, proportional to fuel use) • Catalytic converters and no exhaust system leaks (CO, NOx, particulates, VOCs – no effect on CO2)

  38. See Ref. (10) Local Issues • Vehicle emissions • Activity: Let’s Sock Car Exhaust • Use tube socks to collect particles from vehicle exhaust. • Notes: • Connect when vehicle is cold, run 5 min, let cool 5 min, remove, turn inside out. • Fuel is incompletely burned, and catalytic converters do not function, during 1st 5 minutes with cold engine. • Observe the socks outside (fuel on them)

  39. Local Issues • Vehicle emissions • Activity: Let’s Sock Car Exhaust • Key points: • Emissions will relate directly to engine size (amount of fuel burned in 5 min). • Emissions will vary with age and maintenance. • Only particles are collected: CO, NOx, gaseous VOCs, CO2, water vapor are not.

  40. Local Issues 2. Snowmobiles and wood stoves • Snowmobiles: 2-cycle engines are light, but of the C burned, • ~1/3 is fully burned and emitted as CO2. • ~1/3 is emitted as CO. • ~1/3 is not burned at all and released as gasoline.

  41. Local Issues 2. Snowmobiles and wood stoves • Wood stoves: • Newer wood stoves have catalysts or secondary combustion; • those without emit more particles and VOCs • Can compare by viewing chimney exhaust (don’t be fooled by water fog) • Wood stoves can be a major source of indoor air pollution when smoke is pulled in from outdoors.

  42. Local Issues 3. Indoor air pollution Key issues: • Radon • Molds • Particles and smokes

  43. Local Issues 4. Atmospheric Dispersion • Radiative cooling on clear nights -> cold ground under warmer air. • Air flow over Lake Superior during summer -> cold water under warmer air.

  44. The Effect of Temperature on Air MixingTemperature increasing with height

  45. Warm Air over Cold Water Source: Ref (11)

  46. Cold Air over Warm Water Source: Ref (11)

  47. Lake SuperiorAverage Temperatures Percent Ice-free Source: Ref (12)

  48. Fog forming over warm Portage Lake

  49. Inversions over L.A. Source: Ref. (9)

  50. Local Issues 5. Airborne pollutants and fishing advisories • PCBs: “PolyChlorinatedBiphenyls” • Chemically stable, thermally stable, high dielectric constants. • Used in transformers, as hydraulic fluids, …

More Related