Air Pollution

1

Air Pollution
Earths atmosphere

• provides essential oxygen
• moderates climate via insulative properties
• provides medium for sound
• shields solar radiation incoming particulate
  matter
• has been neglected

2

Two Sources of Atmospheric (Air) Pollution

• Natural Sources
• - forest fires (CO2, ash)
• - volcanic eruptions (sulfur, mercury)

2) Human Origin - primarily since Industrial
Revolution in late 18th century
3

• Air pollution changing precipitation patterns

• Air pollution (particulates) changing temperature

• Air pollution impacting human ecosystem health

4

Major Pollutants

• Carbon monoxide (CO) by-product of converting
  organic compounds
• gt majority in atmosphere from natural sources

problem with small quantity (human- caused)
condensed into small area (cities have 50X gt
conc.) Clean Air Act of 1970 helped reduce
these emissions via fuel-efficient engines
5

2) Sulfur Oxides (SOx) by-product of burning
sulfur-rich coal oil vehicles, energy
industry, factories raw material for acid
deposition respiratory irritant/reduced
function

• Reducing Sox Emissions (Industry)
• Use low-sulfur coal
• Coal cleaning separating out fools gold
• Desulfurize flue gas in smoke stacks with
  scrubbers

6

3) Particulates suspended particles/liquid
industry autos (combustion) wind erosion
slash burn farming in tropics
respiratory dysfunction toxins
particulates
7

• Hydrocarbons
• methane, benzene
• concentrations in urban areas autos VOCs

5) Nitrogen Oxides (NOx) -- combustion NO
NO2
O2
hydrocarbon NOx photochemical smog
8

photochemical smog hydrocarbon NOx
O3 (ozone)

• Hot, humid summer days cars ozone warnings
• Respiratory irritant, damage to lung tissue

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
Ozone damage to plants e.g., necrosis of plant
tissue (O3 via gas exchange)
14
(No Transcript)
15

Controlling Air Pollution (input vs. output
control)

Particulates 1) filter bag house
-traps/collect material 2) electrostatic
precipitator charged small pollutant
particles collected 3) cyclone filter heavy
dust filter removed with cyclone air stream
16
Filter Bag House
17
Filter Bag House
18
Electrostatic Precipitator
19
Cyclone Filter
20
(No Transcript)
21

Controlling Air Pollution
SOx review notes relative to input vs. output
control

Auto Emissions catalytic converters attached
along exhaust system of car cleaning exhaust
of CO, hydrocarbons, and NOx
What about input controls for auto emissions?
gt fuel efficiency lt volume alternative fuels
alternative engines mass transit mgt of urban
sprawl
22
(No Transcript)
23
Reduction Catalyst (A) Oxidation Catalyst (B)
Honeycomb Structure (C) or ceramic beads
24

• Reduction Catalyst vs. Oxidation Catalyst
  (located in honeycomb structure which is coated
  with metal catalysts)
• Reduction platinum rhodium metals
• NOx N2 02
• Oxidation platinum palladium metals
• 02 CO CO2

25

Global Impacts of Air Pollution
Ozone Depletion in the stratosphere (25-50
km) absorbs ultraviolet (UV) radiation
naturally, dynamic equilibrium

chlorofluorocarbons (CFCs) propellant
coolant escape to stratosphere react with
ozone (persistant)
26
(No Transcript)
27

Ozone Depletion CFCl3 UV Cl (free
radical) O3 Cl ClO O2


28
Ozone Hole

• http//www.youtube.com/watch?vqUfVMogIdr8NR1

29

Ozone Depletion
Harmful Effects (next 10-100 yrs)

• exasperate global warming
• UV radiation gt skin cancer
• lt amphibian populations, gt extinction
• altered trophic structure of communities

- 1987 149 nations signed the Montreal Protocol.
Agreed to reduce the manufacturing of CFCs by
1/2 in 1998 and eventually phase out CFCs.
30

Global Impacts of Air Pollution
Global Climate Change (Greenhouse Effect)
CO2, H2O, O3, NO, methane (CH4), and
chlorofluorocarbons (CFCs)

• greenhouse gases trap infrared radiation (IR)
  from leaving atmosphere
• CO2 concentrations on the rise correlated with
  rise in temperatures

31

Global Climate Change

• 1990 2100 projected 2oC increase

Do the Pros Outweigh the Cons? Some Pros lt
heating costs , gt growing season? gt crop
production?
Some Cons gt ocean level (gt 50 cm) , gt
variation in weather patterns, salt water
intrusion, gt species extinction, redistribution
of ag., disease, species..
32

Reducing the Threat of Global Warming

• Reactive vs. Proactive Management
• Optimism vs. Pessimism

• Reduce auto emissions
• Alternative fuels
• Fuel taxes
• Genetically engineered fuel crops
• Stopping Deforestation Increase Restoration
• Population Growth Management

Tenets of Sustainable Development
33

Global Impacts of Air Pollution
Acid Deposition (Acid Rain) acidic rain,
snow, or dust SO2 (sulfur dioxide) -- sulfuric
acid NO2 (nitrogen dioxide) nitric acid

Differential acid precipitation patterns role
of weather patterns in spreading acid precursors
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37

Acid Deposition
But dont volcanoes produce SO2 emissions?

• Remember its a question of (relative to nutrient
  cycling, concentration, and dispersion)
• Spatial Temporal Scale
• Frequency Intensity

38

Acid Deposition
Differential vulnerabilities of ecosystems
dependent on buffering ability (limestone vs.
granite)

• Impacts of acid deposition on northern lake
  systems
• - relation to heavy metals

39

Acid Deposition
Harmful Effects

• gt acidity of soil
• defoliation of vegetation
• fish reproduction impaired (chemotaxis)
• altered trophic structure of aquatic community
• gt heavy metal availability
• abnormal development

40

Reducing Acid Deposition

• Reactive vs. Proactive Management

• Low-Sulfur Coal (S)
• Scrubbers (S)
• Energy Conservation (S N)
• Renewable Energy Resources (S N)

Tenets of Sustainable Development