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the thin layer of gases around Earth , Provides oxygen, Absorbs radiation and moderates climate, Transports and recycles water and nutrients
Over history, the atmosphere has changed. Human activity is now changing the amount of some gases
CO2, methane (CH4), ozone (O3)
The Atmosphere: The atmosphere is layered. What is The atmosphere?
is the layer of gases that surrounds Earth.
bottommost layer (~ 11 km [7-10 miles]), Responsible for Earth's weather: , ALL WEATHER IS IN THE TROPOSPHERE!, The air gets colder with altitude., Tropopause: the boundary that limits mixing between the troposphere and stratosphere.
11-50 km (7-31 mi) above sea level, Drier and less dense, with little vertical mixing, Gets warmer with altitude
The _____ _______ (17-30 km above sea level) greatly reduces the amount of UV radiation that reaches Earth's surface.
blocks UV radiation, Mesosphere: low air pressure, Gets colder with altitude, Thermosphere: top layer
The atmosphere drivers weather and climate:
Weather and climate involve physical properties of the troposphere
Temperature, pressure, humidity, cloudiness, wind
atmospheric conditions within small geographic areas, over short time periods (hours, days)
patterns of atmospheric conditions across large geographic regions over long periods of time
Land and surface water absorb solar energy and radiate heat, causing some water to evaporate.
Air near Earth's surface therefore tends to be warmer and moister than air at higher altitudes.
Large-scale circulation systems produce global climate patterns.:
At large geographic scales, convective air currents contribute to long-term climate patterns. These patterns, combined with temperature variation, help explain why biomes tend to be arrayed in latitudinal bands.
def. air pollutants
are gases and particulate material added to the atmosphere that can affect climate or harm people or other organisms.
In recent decades, government policy and improved technologies have helped us reduce most types of outdoor air pollution (often called ambient air pollution) in industrialized nations.
Natural processes make a great deal of air pollution. Some natural impacts are made worse by human activity and land-use policies.
We create outdoor air pollution. Human activity introduces many sources of air pollution.
Primary pollutants are emitted into the troposphere in a form that can cause harm or that can react to form harmful substances.
Pollutants differ in the amount of time they spend in the atmosphere—called their residence time—because
substances differ in how readily they react in air and in how quickly they settle to the ground.
Clean Air Act legislation addresses _______ in the United States. To address air pollution in the United States, Congress has passed a series of laws, notably the Clean Air Act.
Under the Clean Air Act, the U.S. Environmental Protection Agency (EPA) sets :
nationwide standards for emissions and for concentrations of pollutants in ambient air throughout the nation.
Clean Air Act:
Funds research for pollution control, Sets standards for air quality, limits on emissions. Allows citizens to sue parties violating the standards, Introduced a cap-and-trade program for sulfur dioxide
The EPA sets standards for emissions and pollutants
States monitor air quality:
They develop, implement, and enforce regulations, submit plans to the EPA for approval, The EPA takes over enforcement if plans are inadequate
The EPA sets standards for "criteria pollutants." What are criteria pollutants?
especially great threats to humans, 127 million Americans live in areas that violate standards for at least one criteria pollutant
The EPA and the states focus on six criteria pollutants, pollutants judged to pose especially great threats to human health:
Carbon monoxide, sulfur dioxide, nitrogen dioxide, tropospheric ozone, particulate matter, lead
Carbon Monoxide (CO)
colorless, odorless gas, Produced primarily by incomplete combustion of fuel, From vehicles and engines, industry, waste, combustion, residential wood burning ;Prevents blood hemoglobin from binding with oxygen
_______ _________ is a colorless, odorless gas produced primarily by the incomplete combustion of fuel.
_______ ________ is a colorless gas with a pungent odor that is released when coal is burned and contributes to acid deposition.
Sulfur Dioxide (SO2)
colorless gas with a strong odor, Coal emissions from electricity generation, industry, Can form acid deposition
______ _______ is a foul-smelling reddish-brown gas that contributes to smog and acid deposition. Along with nitric oxide, nitrogen dioxide belongs to a family of compounds called _______ ______.
nitrogen dioxide; nitrogen oxides
What are nitrogen oxides? (NOx)
formed when nitrogen and oxygen react at high temperatures in engines, Vehicles, electrical utilities, industrial combustion
Tropospheric ozone results from the interaction of sunlight, heat, nitrogen oxides, and volatile carbon-containing chemicals.
e) Particulate matter is composed of solid or liquid particles small enough to be suspended in the atmosphere, and able to damage respiratory tissues when inhaled.
f) Lead is a heavy metal that enters the atmosphere as a particulate pollutant released by industrial processes and fuel combustion.
Tropospheric ozone :(03)
a colorless gas, A secondary pollutant created from sunlight, heat, nitrogen oxides, volatile carbon-containing chemicals; a major component of smog., Harms tissues and causes respiratory problems. ;
_________ ________ is composed of solid or liquid particles small enough to be suspended in the atmosphere, and able to damage respiratory tissues when inhaled.
suspended solid or liquid particles, Damages respiratory tissue when inhaled, Primary pollutants: dust and soot, Secondary pollutants: sulfates and nitrates, From dust and combustion processes
______ is a heavy metal that enters the atmosphere as a particulate pollutant released by industrial processes and fuel combustion.
in gasoline and industrial metal smelting, Bioaccumulates and damages the nervous system, Banned in gasoline in developed, but not in developing, countries
EPA monitoring finds that many Americans live where concentrations of criteria pollutants regularly reach ______ levels.
Acid deposition is another transboundary issue
What is Acid deposition?
the deposition of acid, or acid-forming, pollutants from the air onto Earth's surface
From automobiles, electric utilities, industrial facilities
What is atmospheric deposition?
the wet or dry deposition of pollutants (mercury, nitrates, organochlorines, etc.)
Agencies monitor emissions. Agencies monitor emissions of : volatile organic compounds (VOCs),
carbon-containing chemicals that can react to produce ozone and other secondary pollutants.
We have reduced U.S. air pollution.: We have reduced emissions of each of the six monitored pollutants, despite substantial increases in the nation's population.
We have achieved this success as a result of policy steps and technological developments, each motivated by grassroots social demand for cleaner air. Technologies such as baghouse filters, electrostatic precipitators, and scrubbers helped to reduce pollutants. , Concerns over new pollutants are emerging as greenhouse gas emissions continue to rise.
Toxic pollutants pose health risks. What areToxic air pollutants
are substances known to cause cancer, reproductive defects, or neurological, developmental, immune system, or respiratory problems.
Industrializing nations are suffering increasing air pollution. Although the United States and other industrialized nations have improved their air quality...
outdoor air pollution is growing worse in many industrializing countries.
The people of China suffer some of the world's worst air pollution.
China's government is now striving to reduce pollution.
What is Smog?
is an unhealthy mixture of air pollutants that often forms over urban areas as a result of fossil fuel combustion. Since the onset of the industrial revolution, cities have suffered a type of smog we call industrial smog.
Photochemical (brown air) smog:Sunlight drives a chemical reactions between primary pollutants and atmospheric compounds, Forming ozone, NO2, and many other compounds.
Appears as a brownish haze, Formed in hot, sunny cities surrounded by mountains, Morning traffic releases NO and VOCs, Irritates eyes, noses, and throats
Photochemical smog results from a series of reactions. How does Photochemical smog form?
forms when sunlight drives chemical reactions between primary pollutants and normal atmospheric compounds, producing a mix of over 100 different chemicals, with tropospheric ozone often the most abundant.
___, ______, _______ days in urban areas provide perfect conditions for the formation of photochemical smog. We can take steps to reduce smog.
hot, sunny, windless days
ynthetic chemicals (CFCs) deplete stratospheric ozone.
Ozone in the lower stratosphere absorbs the sun's ultraviolet (UV) radiation, UV radiation can damage tissues and DNA
Years of research by hundreds of scientists revealed that certain airborne chemicals destroy ozone, and that most of these _____-_________ substances are human-made.
In particular, researchers pinpointed ________—human-made compounds derived from simple hydrocarbons in which hydrogen atoms are replaced by halogen atoms such as chlorine, bromine, or fluorine.
Industry was mass-producing one class of halocarbon, ___________________ (CFCs), at 1 million tons per year in the 1970s.
halocarbons used as refrigerants, in fire extinguishers, in aerosol cans, etc., They stay in the stratosphere for a century
In 1985, researchers shocked the world by announcing that stratospheric ozone levels over Antarctica in springtime had ________ by nearly half in just the previous decade, leaving a thinned ozone concentration that was soon dubbed the ozone hole.
The Montreal Protocol addressed ozone depletion.
As a result, we have evidently stopped the Antarctic ozone hole from growing worse. However, the ozone layer is not expected to recover completely until 2060-2075.
Because of its success in addressing ozone depletion, the Montreal Protocol is widely viewed as a model for international cooperation on other global problems, from
biodiversity loss to persistent organic pollutants to climate change.
Acid deposition is another transboundary issue: What is Acid deposition?
the deposition of acid, or acid-forming, pollutants from the air onto Earth's surface, From automobiles, electric utilities, industrial facilities
_____ __________ refers to the deposition of acidic or acid-forming pollutants from the atmosphere onto Earth's surface. This can take place by precipitation, commonly referred to as ____ _____.
acid deposition; acid rain
.Acid deposition is one type of __________ ___________, which is the wet or dry deposition of a variety of pollutants.
What is atmospheric deposition?
the wet or dry deposition of pollutants (mercury, nitrates, organochlorines, etc.)
Acid deposition originates primarily with:
the emission of sulfur dioxide and nitrogen oxides, largely through fossil fuel combustion by automobiles, electric utilities, and industrial facilities.
Acid deposition has many impacts.
Acidic deposition damages crops, erodes stone buildings, corrodes cars, and erases the writing on tombstones. ;Because the pollutants leading to acid deposition can travel long distances, their effects may be felt far from their sources.
We have begun to address acid deposition. : Policy has helped us address acid deposition.
The economic incentives created by this cap-and-trade program encourages polluters to invest in technologies such as scrubbers, and to devise other ways to become cleaner and more efficient., Meanwhile, in the industrializing world, acid deposition is becoming worse.
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