18.2 Air Pollution

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18.2 Air Pollution
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• What is air pollution?
• When did air pollution begin?

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Answers

• What is air pollution? Presence of chemicals in
  atmosphere in high enough concentrations to harm
  organisms, ecosystems, or structures/materials
• When did it start By Humans, with the
  application of fire as a resource

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• The smoke from fires in the cave were unhealthy

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Middle Ages

• Haze of wood smoke hung over cities

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18-2 What Are the Major Outdoor Pollution
Problems?

• Concept 18-2 Pollutants mix in the air to form
  industrial smog, mostly the result of burning
  coal, and photochemical smog, caused by motor
  vehicle, industrial, and power plant emissions.

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Killer fogs

• Smog Smoke Fog
• London had several episodes of Killer Fogs
• Worst 1952 yellow fog lasted 5 days, killed
  4000-12,000 Londoners
• Visibility so low that people walking outside
  could not see their feet (visibility of 1 foot)

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1952

• Sources Industry, diesel buses, coal fired home
  heat systems

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Case Study Air Pollution in the Past (2)

• United States
• 1948 Donora, PA first U.S. air pollution
  disaster
• Valley,40 sick
• 1963 NYC
• (300 killed)
• Global problem

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South Asias Massive Brown Cloud, today

• Asian Brown Cloud
• Causes (clearing forests, industrial pollution
• Chemical composition Dust, wood ash, acidic
  compounds, toxic metals (Hg, Pb), fly ash
• Areas impacted (India to China)
• Air pollution connects the world
• 2 weeks to circle globe
• 33 of toxic mercury in LA air
• Steps taken in China and India to reduce air
  pollution
• A fixable problem. Solutions?

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The Asian Brown Cloud
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Air Pollution in Shanghai, China, in 2004
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Air Pollution Comes from Natural and Human
Sources (1)

• Natural sources
• Dust blown by wind
• Pollutants from wildfires and volcanoes
• Volatile organics released by plants
• Withdrawing groundwater

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Air Pollution Comes from Natural and Human
Sources (2)

• Human sources mostly in industrialized and/or
  urban areas
• Stationary sources (Industry, power plants,
  landfills?)
• Mobile sources (Cars, tractors, Airplanes)

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Types of pollutants

• Primary pollutants emitted directly from sources
• Secondary pollutants formed from reaction with
  air

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Primary Pollutants
Secondary Pollutants
CO
CO2
SO2
NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended particles
H2O2
O3
PANs
Most NO3- and SO42- salts
Sources
Natural
Stationary
Mobile
Fig. 18-4, p. 472
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Some Pollutants in the Atmosphere Combine to Form
Other Pollutants

• Air quality is improving in developed countries!!
• (why?)
• Much more needs to be done in developing
  countries
• 1.1 Billion live where air is unhealthy to
  breathe
• Indoor pollution biggest threat to the poor
• Causes of indoor pollution?

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Indoor Air Pollution
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What Are the Major Outdoor Air Pollutants? (1)

• Carbon oxides
• Carbon monoxide (CO)
• CO Sources (exhaust, burning forests, stoves
  tobacco smoke
• Human health and environmental impact
• Reacts with blood, reduces it ability to
  transport oxygen to cells/tissues
• Chronic exposures leads to heart attacks, lung
  disease
• high levels lead to headaches, vomiting, mental
  impairment, coma, death

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Other carbon oxides

• Carbon dioxide (CO2)
• CO2 sources (fossil fuels, burning forests)
• Emissions have been accelerating since 1950
• Danger contributes to global warming by
  increasing the greenhouse effect

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What Are the Major Outdoor Air Pollutants? (2)

• Nitrogen oxides (NO) and nitric acid (HNO3)
• Sources (car exhaust, and coal burning plants,
  Lightning, soil bacteria)
• Acid deposition (when NO reacts with water
  vapor)
• Photochemical smog (combined with sunlight,
  exhaust)
• t

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Human health and environmental impact of nitrogen
oxides

• Irritates eyes, nose, throat
• Aggravates lung ailments (asthma)
• Impairs immune system
• Suppress plant growth
• Reduce visibility

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Sulfur dioxide (SO2) and sulfuric acid (H2SO4)

• Sources 1/3 natural (volcano) 2/3 man-made
• Human sources coal burning, refining/smelting
• Feeds the Asian Brown Cloud
• Human health and environmental impact
• Reduce visibility, aggravate breathing
• Damage crops, trees, soils, acidify lakes
• Corrode metal, paint, leather, paper, stone

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Statue Corroded by Acid Deposition and Other
Forms of Air Pollution, RI, U.S.
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(No Transcript)
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What Are the Major Outdoor Air Pollutants? (3)

• Particulates
• Suspended particulate matter (SPM)
• Fine
• Ultrafine
• Sources
• Human health and environmental impact

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What Are the Major Outdoor Air Pollutants? (4)

• Ozone (O3)
• Sources
• Human and environmental impact
• Volatile organic compounds (VOCs)
• Hydrocarbons and terpenes
• Sources
• Human and environmental impact

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Chemical Reactions That Form Major Outdoor Air
Pollutants
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Stepped Art
Table 18-1, p. 473
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Science Focus Detecting Air Pollutants

• Chemical instruments
• Satellites
• Nanotechnology
• Biological indicators
• Lichens

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Natural Capital Lichen Species, Vulnerability
to Air Pollutants
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Case Study Lead Is a Highly Toxic Pollutant (1)

• Does not break down in the environment
• Sources
• Human health and environmental impact
• Most vulnerable

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Case Study Lead Is a Highly Toxic Pollutant (2)

• Reduction of lead (Pb)
• Unleaded gasoline
• Unleaded paint
• Still problems
• 2007 toys with Pb paint recalled
• Global ban on lead in gasoline and paint

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SOLUTIONS
Lead Poisoning
Prevention
Control
Replace lead pipes and plumbing fixtures
containing lead solder
Phase out leaded gasoline worldwide
Phase out waste incineration
Remove leaded paint and lead dust from older
houses and apartments
Ban use of lead solder
Sharply reduce lead emissions from incinerators
Ban use of lead in computer and TV monitors
Remove lead from TV sets and computer monitors
before incineration or land disposal
Ban lead glazing for ceramicware used to serve
food
Test for lead in existing ceramicware used to
serve food
Ban candles with lead cores
Test existing candles for lead
Test blood for lead by age 1
Wash fresh fruits and vegetables
Fig. 18-7, p. 476
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Burning Coal Produces Industrial Smog

• Chemical composition of industrial smog
• Reduction of this smog in urban cities of the
  United States
• China and smog
• Human deaths

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How Pollutants Are Formed from Burning Coal and
Oil, Leading to Industrial Smog
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Ammonium sulfate (NH4)2SO4
Ammonia (NH3)
Sulfuric acid (H2SO4)
Carbon monoxide (CO) and carbon dioxide (CO2)
Water vapor (H2O)
Sulfur trioxide (SO 3 )
Oxygen (O2)
Sulfur dioxide (SO2)
Burning coal and oil
Oxygen (O2)
Carbon (C) in coal and oil
Sulfur (S) in coal and oil
Fig. 18-8, p. 476
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Stepped Art
Fig. 18-8, p. 476
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Sunlight Plus Cars Equals Photochemical Smog

• Photochemical Smog
• Chemical composition
• Sources
• VOCs NO2 Heat Sunlight yields
• Ground level O3 and other photochemical oxidants
• Aldehydes
• Other secondary pollutants
• Human health and environmental impact

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A Model of How Pollutants That Make Up
Photochemicals Are Formed
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PANS and other pollutants
Volatile organic compounds (VOCs)
Ozone (O3)
Oxygen (O2)
Nitric oxide (NO) Oxygen atom (O)
Water vapor (H2O)
Hydrocarbons
UV radiation
Peroxyacyl nitrates (PANs)
Nitrogen dioxide (NO2)
Oxygen (O2)
Nitric oxide (NO)
Oxygen (O2)
Burning fossil fuels
Nitrogen (N) in fossil fuel
Fig. 18-9, p. 477
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Global Outlook Photochemical Smog in Santiago,
Chile
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Several Factors Can Decrease or Increase Outdoor
Air Pollution (1)

• Outdoor air pollution may be decreased by
• Settling of particles due to gravity
• Rain and snow
• Salty sea spray from the ocean
• Winds
• Chemical reactions

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Several Factors Can Decrease or Increase Outdoor
Air Pollution (2)

• Outdoor air pollution may be increased by
• Urban buildings
• Hills and mountains
• High temperatures
• Emissions of VOCs from certain trees and plants
• Grasshopper effect
• Temperature inversions

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A Temperature Inversion
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Descending warm air mass
Warmer air
Inversion layer
Inversion layer
Sea breeze
Increasing altitude
Decreasing temperature
Fig. 18-11, p. 478
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Animation Formation of photochemical smog
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Animation Thermal inversion and smog