Transcript Chapter 17: Atmospheric Science and Air Pollution

Chapter 17: Atmospheric Science
and Air Pollution
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Atmosphere
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surrounds earth
mostly of N2, O2, Ar
today's altering molecules
consist of CH4, O3, CO2
made up of layers
ozone layer
Other Atmospheric Properties
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atmospheric pressure
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force per unit of area that air exerts on the surface
of Earth
declines with altitude
atmospheric humidity
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ratio of water vapor contained in a given volume
of air in relation to it's maximum amount possible
the more humidity the hotter it seems
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Seasons
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determined by the positioning in relation to the sun
atmosphere absorbs 70% of the energy
the shorter the distance, the more intense the sun
rays
solar radiation intensity is lower at the poles and
higher at the equator
tilting of the planet causes the seasons to occur
Air Circulation
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known as convective
circulation
caused by differences in
humidity and temperature
warm air rises as it is less dense
cold air descends becoming denser
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Weather & Climate
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Weather specifies atmospheric conditions
over short periods of time and related to
relatively small areas
Climate describes patterns of atmospheric
conditions across large regions and over
long periods of time
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Weather
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depends on the fronts
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cold→ thunderstorms
warm→ light rain
affected by the pressure
systems
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high→ fair to dry weather
low→ results in clouds and precipitation
Thermal Inversion
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cooler air appears under warmer air
prevents normal convective circulation to
occur
pollution is trapped under the inversion layer
creating health problems like asthma
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killer smog in London
asthma in San Joaquin valley
Global Climate Patterns
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Hadley cells: between equator and 30º
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heavy rain at the equator
arid at 30º
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Global Climate Patterns
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Ferrer cells and polar cells lift air creating
rain at ~60º
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Wind Patterns
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caused by the interaction of Hadley and
Ferrer cells and Earth's rotation
Coriolis effect: winds are curved
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Outdoor Air Pollution
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air pollutants
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natural sources
human made sources
Natural Pollutants
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we have no control, occur naturally
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volcano eruptions
Mt. Pinatubo
produces particles
circle the globe and
remain in suspension
for months
acid rain
affect temperature
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Natural Pollutants
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dust storms
Texas dust storm 1930's
Arthur Rothstein, photographer, April, 1936. (Library of Congress)
Dallas dust storm 2007
www.panoramio.com
Natural Pollutants
Fires
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2000
www.gsfc.nasa.gov
soot and gases
fuel buildup
slash-and-burn
in tropics
El Niño
T
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LA
TX
Gulf Coast
Human Created Outdoor Pollution
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primary pollutants
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emitted directly to the troposphere
can be harmful to the environment
can form chemicals harmful to the environment
secondary pollutants
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react with constituents of the atmosphere
Clean Air Act
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1970
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set stricter standards for air quality
imposed limits to emissions
funds for pollution control research
1990
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strengthen air quality standards
emission trading program for sulphur dioxide
other emission trading programs developed
EPA Standards
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carbon monoxide (CO)
sulphur dioxide (SO2)
nitrogen dioxide (NO2)
tropospheric ozone (O3)
particulate matter
lead (Pb)
Carbon Monoxide
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colorless
odorless
incomplete combustion
in the U.S. 78% of it comes from vehicles
small concentrations can be lethal to most
living organisms
Sulphur Dioxide
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colorless
pungent odor
power plants of coal
once in the atmosphere SO2 reacts forming
SO3 and later forming H2SO4
H2SO4 forms acid rain
London 1952
www.epa.gov
Nitrogen Oxides
Los Angeles
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contributes to smog
NO2 is foul smelling, redish brown gas
NOx cause acid rain
product of combustion engines
vehicles produce 50% of the U.S. NOX
electricity production and industry the rest
Ozone
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product of sunlight + heat + NOX + carbon chemicals
health risk because of its instability→ O2 + Oxygen ion
oxygen ion can cause tissue damage
tissue damage can cause respiratory problems
www.epa.gov
Los Angeles
Particulate Matter
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particles suspended in air
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primary pollutants → dust and soot
secondary pollutants → sulphates and nitrates
can damage respiratory tissues
wind-blown result of human activities
Lead
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particulate matter
enters food chain
can cause nervous system malfunction
present in gasoline to improve performance
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industrialized nations phased out leaded
gasoline
industrial metal smelting is the problem now
VOCs
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volatile organic compounds
hydrocarbons
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methane forms part of natural gas
propane used as portable fuel
butane used in portable lighters
octane component of gasoline
Pollutants in the U.S.
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2006
137 trillion tons
EPA data
www.epa.gov
Pollution Decreased since 1970
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emissions declined 53% since 1970
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cleaner burning vehicles
catalytic converter
clean coal technology
baghouse filters
electrostatic precipitators
scrubbers
phase-out of lead in gasoline
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Toxic Pollutants
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188 toxic pollutants identified by the Clean Air Act in
1990
effects on people
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cancer
reproductive defects
neurological problems
developmental problems
affect the immune system
respiratory diseases
Policy: Bush Administration
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elimination of new source review of 1977
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new pollution targets
retrofitting aging plants with new technologies
industry protested: too costly
Bush Administration exempted older plants
allowed installing only "the best available"
technology IF they ever upgraded the plant
Clear Skies (stopped by the Senate in 2005)
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from command-and-control to a market-based cap-andtrade
Smog
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fogs polluted by smoke= smog
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industrial smog
photochemical smog
London 1952
Industrial smog
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gray-air smog
coal or oil burning
CO, CO2, soot
mercury and sulfur in the carbon sample
sulfur reacts forming SO2
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sulphuric acid
ammonium sulphate
Problems today: China, India, Eastern Europe
Photochemical smog
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requires light
brown-air smog
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Houston 2000
ozone
NOx
VOCs
irritates eyes, nose, throat
car inspections
reduction of vehicles driven per day
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allow certain cars to drive certain days of the week
promote mass transit
Problems at Rural Areas
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airborne pesticides
industrial pollutants from cities, factories and
power plants migrate
methane from cattle (18%)
feedlots
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CH4, dust, NH4, SOx
can cause respiratory problems
China
Industrialization
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is worsen air quality
caused by factories and power plants
emissions are released with little effort to control
pollution
China & India have 58% of premature deaths
worldwide (WHO)
Asian brown cloud
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reduces sunlight
decreases productivity
Synthetic Chemicals
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CFCs (chlorofluorocarbons) Arctic hole
affects the ozone layer
creating the ozone hole in Antarctica
increases UV radiation
leads to more skin cancer
ecological effects still unknown
hole in the arctic
Montreal Protocol of 1987
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addressed ozone depletion
180 nations agreed to cut CFCs production
in half
production and use has dropped by 95%
alternative chemicals
CFCs take very long to brake down
www.epa.gov/cppd
Acid Deposition
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originates with the NOx and SOx
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forms of precipitation known as acid rain
fog
dry particles
pollutants react with water, O2, oxidants
produce compounds of low pH (acids)
these are suspended in the troposphere before
falling as rain
can cause political bickering
Acid Rain
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alters soil composition because:
leaches chemicals from the soil
harming plants and soil organisms
also mobilizes toxic chemicals
converts them to soluble forms
affects agriculture
affect lakes and rivers
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causing high mortality in fishes and amphibians
Acid Rain
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erosion of buildings
corrodes cars
erosion of statues and obelisks
has not been reduced as expected in 1990
more reduction of sulphur oxides and
nitrogen oxides need to occur
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Indoor Air Pollution
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higher concentration of pollutants indoor than
outdoor
workplaces, schools, homes
volatile chemicals in the air
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insecticides
cleaning fluids
plastics
chemically treated wood
Other Sources
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wood burning
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chimneys
cooking
tobacco smoking
radon
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Indoor VOC Pollution
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perfumes
paints
plastics
oils/candles
cleaning fluids
adhesives (glues)
pesticides and insecticides
ink (fax, photocopiers, printers)
color films
Living Organisms also Pollute
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dust mites
animal dander
mold
bacteria
THE END