Air Pollution

1
Air Pollution

• Chapter 19

2
Facts about Air

• 78.08 is Nitrogen (N2)
• 20.95 is Oxygen (O2)
• 0.93 is Argon (Ar)
• 0.03 is Carbon Dioxide (CO2)

3
What services does the atmosphere provide for the
earth?

• Blocks UV radiation that is emitted by the sun.
• Moderates the climate on earth
• Redistributes water in the hydrologic cycle

4
Definition of Air Pollution

• Gases, liquids and solids present in the
  atmosphere in high enough levels to harm
  organisms or materials
• Primary air pollutants harmful chemicals that
  enter the atmosphere directly.
• Secondary air pollutants harmful chemicals that
  forms in the atmosphere when a primary pollutant
  reacts with other air pollutants or natural
  substances in atmosphere.

5
Major Classes of Pollutants

• Particulate matter solid and liquid particles
  that are suspended in the atmosphere.
• Solid particulate matter dust
• Liquid particulate matter mists
• Effects
• Reduces visibility by scattering absorbing
  sunlight
• Corrodes metals
• Erodes buildings materials
• Dangerous when inhaled

6
Major classes of Air Pollutants (cont.)

• 2. Nitrogen Oxides gases produced by chemical
  interactions between nitrogen oxygen when a
  source of energy produces high temperatures.
• - Group called NOx consists of nitric oxide
  (NO), nitrogen dioxide (NO2) and nitrous oxide
  (N20)
• -Effects
• inhibits plant growth
• aggravates health problems
• photochemical smog acid deposition
• corrodes metals
• depletes stratosphere of ozone.

7
Major classes of Air Pollutants (cont.)

• Sulfur oxides produced by the chemical
  interactions between sulfur and oxygen
• Sulfur dioxide (SO2) is an emitted air pollutant
  and a primary pollutant
• Sulfur trioxide (SO3) is a secondary air
  pollutant that forms when sulfur dioxide reacts
  with O2 in the air
• Reacts with H20 to form sulfuric acid
• Effects
• Corrosion (acid deposition)
• Irritate respiratory tracts

8
Major classes of Air Pollutants (cont.)

• Carbon Oxides including carbon monoxide and
  carbon dioxide
• Carbon monoxide is the largest quantity of
  pollutant except C02
• Effects bloods ability to carry oxygen.
• Carbon dioxide is a greenhouse gas.

9
Major classes of Air Pollutants (cont.)

• Hydrocarbons
• Compounds containing only hydrogen carbon
• Simplest form is methane (CH4)
• Smaller hydrocarbons are gases at room
  temperature.
• Medium hydrocarbons are liquid at room
  temperature and many are volatile
• Largest hydrocarbons are solids at room
  temperature.
• Effects
• Part of photochemical smog
• Methane is a greenhouse gas

10
Major classes of Air Pollutants (cont.)

• Ozone (O3)
• In the stratosphere ozone present is good as it
  blocks the UV radiation emitted from sun.
• In the troposphere ozone reacts with sunlight,
  NOx, and hydrocarbons to form photochemical smog
• Reduces visibility
• Stresses plants
• Causes health problems.

11
Major classes of Air Pollutants (cont.)

• Air toxics or pollutants
• - Lots of other chemicals

12
What are the main sources of primary air
pollutants?

• Transportation mobile sources
• Industries - stationary sources, top 3 are
  chemical, metal and paper industries.
• Mobile sources trucks/autos, release NOx,
  Carbon oxides, hydrocarbons, particulates
• Stationary sources emit particulates sulfur
  oxides as well as NOx, hydrocarbons carbon
  oxides

13
What is hydrocarbon isoprene?

• It is hydrocarbons emitted from trees at high
  temperatures
• It is a natural pollutant

14
Effects of Pollution

• Damages organisms
• Reduces visibility
• Corrosion
• Reduce crop plants productivity
• Harm respiratory tracts
• Acid deposition
• Global temperature change
• Stratospheric ozone depletion

15
Human effects of Air Pollution

• Eye irritation
• Respiratory tract inflammation
• Suppress immune system
• Respiratory illness such as asthma emphysema,
  chronic bronchitis

16
What is smog?

• Smog is air pollution that reduces visibility.
• Industrial smog smoke pollution consisting
  primarily of particulates sulfur oxides
• Photochemical smog brownish-orange hazard
  substances resulting from chemical interaction of
  NOx, hydrocarbons, and tropospheric ozone.

17
What are the ingredients of smog?

• Photochemical smog comes from
• Autos
• Bakeries
• Dry cleaners

18
Thermal Inversion/Temperature Inversion

• Air near ground is colder than air at higher
  levels
• Traps polluting gases and particulates matter
  down near ground
• Occurs often in valleys, near coasts, or leeward
  side of mountains.
• Animation

19
Urban Heat Island

• Localized heat buildup
• Increases number of thunderstorms
• Contribute to buildup of pollutants especially
  particulate matter (dust domes)

20
How can we control air pollution?

• Fit smokestacks with electrostatic precipitators,
  fabric filters, scrubbers to remove particulates.
• Careful land excavating to keep dust down.
• Temperature reduction in autos industry to
  reduce NOx formation
• Use low sulfur fuels and alternative energy
  sources.
• Use no tillage practices less nitrogen-based
  fertilizers used.
• Catalytic afterburners to oxidize unburned gasses.

21
Air Pollution Regulations

• Clean Air Act
• Authorizes the EPA to set limit on amount of
  specific air pollutants permitted.
• Focuses on lead, particulate matter, sulfur
  dioxide, carbon monoxide, NOx, ozone with maximum
  allowed concentration.
• Sets levels for attainment and ranks
  non-attainment areas as marginal to extreme.

22
Air Pollution Regulations (cont.)

• In California, air quality managed by Air
• Quality Management Districts.
• Ours is Bay Area Quality Management District
  (BAAQMD)

23
Where is pollution the worst?

• 5 worst Cities for air pollution?
• Mexico City, Mexico
• Beijing, China
• Shanghai, China
• Tehran, Iran
• Calcutta, India

24
Air Pollution in Bay Area

• Pollutants do not stay in the Bay Area.
• Pollutants go to Central Valley, Sierras, and can
  even head south.
• Air Quality Index

25
What compounds stay in the environment?

• Persistent compounds these that do not readily
  breakdown and accumulate in the environment.
• Example PCB, Dioxins, DDT, Pesticides,
• Global Distillation effect volatile chemicals
  evaporate for land, are moved by winds to higher
  latitudes where they condense and fall to the
  ground.

26
Indoor Air Quality

• Common contaminants include
• Radon
• Cigarette smoke
• Carbon monoxide
• Formaldehyde
• Household pesticides solvents
• Ozone
• Asbestos
• Particulates
• Viruses, bacteria, fungi
• Dust mites
• Pollen

27
What is sick building syndrome?

• The presence of air pollution inside a building
  causing health effects such as eye irritation,
  nausea, headaches, fatigue, depression, colds.

28
Radon

• Colorless, tasteless, naturally-occurring
  radioactive gas resulting from radioactive decay
  of uranium in earth.
• Emits alpha particles, a form of ionizing
  radiation that is very damaging to tissue but
  doesnt penetrate very far
• Can cause cancer, mostly due to inhalation

29
Asbestos

• Naturally occurring mineral that does not burn or
  conduct heat.
• Some kinds can separate into long thin fibers
  (friable) that can be breathed in.
• May cause lung cancer

30
Noise Pollution

• Sound is caused by vibrations in the air
• Noise pollution is sound that is loud or
  disagreeable
• Intensity loudness measured in decibels (db)
  or on a modified decibel scale. The decibel A
  (dbA) scale focuses on high pitched sounds.
• Hearing damage loud, high-pitched noise injures
  the hair cells in the cochlea (the spiral inner
  tube in the ear)
• Noise pollution causes increased heart rate,
  dilates pupils and causes muscle contractions.

31
EMF

• Electric and magnetic fields (EMF)
• Associated with power lines, electric blankets,
  and microwaves.