Transcript Pollution - Denton ISD

Pollution
Pollution

Any substance (matter or energy) that is added to the
biosphere by humans at a rate greater than what can
be rendered harmless by the environment.
◦ Anything that can cause harm to the environment by human
activity.

Two main types of Pollutions:
◦ Point Source Pollution – where pollutants are released from
a single identifying site.
 Ex: a factory or sewage plant
◦ Non-Point Source Pollution – where pollutants are released
from many unidentifying areas.
 ex: agricultural areas, urban traffic
POINT SOURCE VS NON-POINT SOURCE
Draw your own table in your notes.
Using the information
from your warm-up last
class and
textbook/companion bk :
1.
2.
3.
Determine 3 specific
areas of Denton
where we can find
these pollution
sources. Name these
areas.
Determine which type
of pollutants comes
from each source.
Where in Denton will
these pollutants be
affected.
Point Source
Non-Point Source
1.
1.
2.
2.
3.
3.
Atmosphere & Air Pollution
A little background:
The atmosphere is the envelope of gases that surround
our planet
• It is a very thin layer compared to the radius of the
Earth
• We refer to this layer informally as “air”
• The majority of the energy that drives the atmosphere
is from the Sun.
• The atmosphere receives most of this energy from the
surface.
• Imbalances of energy drive the winds. Eventually, all
energy degrades down to friction.
•

We commonly express the state of the
atmosphere by measuring it using the following
variables:
◦
◦
◦
◦
◦
◦
◦
Pressure
Temperature
Wind
Humidity
Cloud cover
Precipitation type and amount
Visibility (distance one can see horizontally)
Dry air (neglecting water vapor) is composed of
the following gases:
Nitrogen (N2)
= 78%
Oxygen (O2)
= 21%
Argon (Ar) = 1%
Trace Gases
Dust, bacteria, and other particulates

Trace Gases
◦ Gases that are only found by examining a
million or billion air molecules
◦ Examples include:





Carbon Dioxide (CO2) = 340 ppmv
Neon (Ne) = 18 ppmv
Helium (He) = 5 ppmv
Methane (CH4) = 2 ppmv
Hydrogen (H2) = 0.5 ppmv
Troposphere
Stratosphere
Mesosphere/Thermosphere
STRUCTURE AND SCIENCE OF THE
ATMOSPHERE

The atmosphere
consists of several
layers with different
temperatures,
pressures, and
compositions.
Figure 19-2
Atmospheric Circulation
(convection)
• Heated air rises at
equator
Maximum
Sun
warming
• Cooler air descends
at poles
Solar Energy and Global Air
Circulation: Distributing Heat

Global air
circulation is
affected by the
uneven heating of
the earth’s surface
by solar energy,
seasonal changes in
temperature and
precipitation.
Figure 5-3
Coriolis Effect
Coriolis effect deflects north-south
winds into east-west winds
Coriolis Effect breaks up
Global Circulation

On Earth the large
circulation cell breaks up
into 3 smaller ones,
moving diagonally

Other worlds have more
or fewer circulation cells
depending on their
rotation rate
Convection Currents
Convection cells
Total
Atmosphere
Circulation
Hadley Cell
Air rises at the Equator due to high insolation at the
surface (convection)
 The belt of rising air and clouds is called the
Intertropical Convergence Zone (ITCZ)
 Large amounts of latent heat are released in the ITCZ
 Air blows in at the surface to replace the rising air;
these winds are the trade winds
 Wind speeds beneath the ITCZ are low, and this zone is
also called the doldrums
 Air sinks in the subtropics as part of the Hadley Cell
and forms the subtropical highs
 The winds in the subtropical highs are also very slow,
and this zone is called the “horse latitudes”

Polar Cell
Thermally-direct cell at high latitudes
 Rising air occurs at a boundary between cold,
polar air and warmer air in the mid-latitudes,
called the polar front
 Extremely cold air at the poles lead to surface
high pressure
 Winds blowing from the north to the south
turn to blowing from the east due to the
Coriolis force, so the surface winds are called
the polar easterlies

Ferrel Cell
This cell is thermally-indirect (hot air sinks and cold air
rises)
 The upper branch of the Ferrel Cell predicts easterly
winds aloft, but they are observed to westerly
 Even though the complete cell doesn’t exist, the rising
air at the polar front, the sinking air at the subtropical
high pressures, and the correct surface winds exist
 Surface flow from the south turns to the blowing from
the west, resulting in our wind zone of the “prevailing
westerlies”
 The mid-latitudes is a very complex region, with many
secondary circulation features (storms) present

Sea Breeze
 These
are ocean-to-land breezes
that occur during the day.
Land Breeze
 These
are land-to-ocean breezes
that occur at night.
Valley Breeze
 As
the wind blows from the plains
into a valley between two mountains,
the wind must divert into a smaller
area. This causes high winds to form
through the valleys.
Mountain Breeze
 Cool
air coming from the top of
the mountain sinks down on the
eastern slope, causing increased
winds on the mountain.
Air Pollution
Pollution – any contaminate to the Earth or
Atmosphere so that the environment
systems are negatively affected.
Regularly monitored air pollutants:
Sulfur Dioxide, Oxides of Nitrogen,
ozone (O3), volatile organic compounds and
particles.
EPA Regulations: Denton
Air Pollution
 Primary
Pollutants – methane, ozone,
dust particles, microorganisms, and
chlorofluorocarbons (CFC’s)
 Causes of Primary Pollutants –
factories, cars, wind and soil, volcanoes,
forest fires, pollen, decaying plants, salt
particles from the sea, and refrigerants.
AIR POLLUTION

Some primary air pollutants may react with one
another or with other chemicals in the air to form
secondary air pollutants.
Figure 19-3
Major Air Pollutants

Carbon oxides:
◦ Carbon monoxide (CO) is a highly toxic gas that
forms during the incomplete combustion of carboncontaining materials.
◦ 93% of carbon dioxide (CO2) in the troposphere
occurs as a result of the carbon cycle.
◦ 7% of CO2 in the troposphere occurs as a result of
human activities (mostly burning fossil fuels).
 It is not regulated as a pollutant under the U.S. Clean Air Act.
Major Air Pollutants

Nitrogen oxides and nitric acid:
◦ Nitrogen oxide (NO) forms when nitrogen
and oxygen gas in air react at the highcombustion temperatures in automobile
engines and coal-burning plants. NO can also
form from lightening and certain soil bacteria.
 NO reacts with air to form NO2.
 NO2 reacts with water vapor in the air to form
nitric acid (HNO3) and nitrate salts (NO3-) which
are components of acid deposition.
Major Air Pollutants

Sulfur dioxide (SO2) and sulfuric acid:
◦ About one-third of SO2 in the troposphere
occurs naturally through the sulfur cycle.
◦ Two-thirds come from human sources, mostly
combustion (S+ O2  SO2) of sulfurcontaining coal and from oil refining and
smelting of sulfide ores.
◦ SO2 in the atmosphere can be converted to
sulfuric acid (H2SO4) and sulfate salts (SO42-)
that return to earth as a component of acid
deposition.
Major Air Pollutants

Suspended particulate matter (SPM):
◦ Consists of a variety of solid particles and
liquid droplets small and light enough to
remain suspended in the air.
◦ The most harmful forms of SPM are fine
particles (PM-10, with an average diameter <
10 micrometers) and ultrafine particles (PM2.5).
◦ According to the EPA, SPM is responsible for
about 60,000 premature deaths a year in the
U.S.
Major Air Pollutants

Ozone (O3):
◦ Is a highly reactive gas that is a major
component of photochemical smog.
◦ It can
 Cause and aggravate respiratory illness.
 Can aggravate heart disease.
 Damage plants, rubber in tires, fabrics, and paints.
Major Air Pollutants

Volatile organic compounds (VOCs):
◦ Most are hydorcarbons emitted by the leaves
of many plants and methane.
◦ About two thirds of global methane emissions
comes from human sources.
◦ Other VOCs include industrial solvents such
as trichlorethylene (TCE), benzene, and vinyl
chloride.
 Long-term exposure to benzene can cause cancer,
blood disorders, and immune system damage.
Major Air Pollutants

Radon (Rn):
◦ Is a naturally occurring radioactive gas found
in some types of soil and rock.
◦ It can seep into homes and buildings sitting
above such deposits.
Water Pollution
Poisoned Waters – Frontline PBS
Take notes: answer the questions (set 1)
1) Where does waste from our toilets and sink wind
up?
2)
What about chemicals that we use to clean our
homes, wash our cars, fertilize our lawns?
3)
What happens to our makeup, deodorant,
shampoos and other personal care items when we
take a shower?
4)
What about pharmaceuticals tossed in the toilet?
Question set 2
1)
Where does your drinking water come from? Can you
think of anything that might pollute that source of water?
2)
What problems have scientists detected in nature that they
believe are caused by “emerging contaminants”?
3)
Are humans potentially vulnerable to some of these same
chemicals?
4)
What should the government and/or industry do about
these emerging contaminants?
5)
What can you do to make water safer for yourself, your
community and the fish?