EPA 608 UNIVERSAL UPDATED ACTUAL EXAM QUESTIONS CORRECT ANSWERS GRADED A
PLUS
Question:
Ozone.
Answer:
A form of oxygen made of three bonded oxygen atoms that occurs naturally in the upper atmosphere
where it absorbs harmful ultraviolet radiation, while at ground level it can act as a pollutant that
irritates lungs and contributes to smog.
Question:
Where does ozone accumulate in the atmosphere?
Answer:
In the two lowest layers of Earth's atmosphere; between the stratosphere, and the troposphere. Most
of it is in the stratosphere, forming a concentrated layer high above Earth where it absorbs
ultraviolet radiation.
Question:
Chlorofluorocarbons (CFCs).
Answer:
Man-made chemical compounds composed of chlorine, fluorine, and carbon that were widely used
in refrigeration, air conditioning, aerosols, and foam production. They are extremely stable in the
lower atmosphere, allowing them to rise to the stratosphere where ultraviolet radiation breaks them
apart, releasing chlorine that destroys protective ozone. Their strong ozone depletion effect led to
global phaseout agreements such as the Montreal Protocol.
Question:
How do chlorofluorocarbons destroy ozone?
,Answer:
They rise into the upper atmosphere where strong ultraviolet radiation breaks them apart, releasing
chlorine atoms. These chlorine atoms react with ozone molecules, removing oxygen atoms and
turning them into ordinary oxygen. One chlorine atom can repeat this process many times, causing
significant thinning of the protective layer.
Question:
Why is the ozone layer important?
Answer:
It protects life on Earth by absorbing most of the Sun's harmful ultraviolet radiation before it reaches
the surface. Without this protective layer, increased UV exposure would raise risks of skin cancer,
eye damage like cataracts, weakened immune systems, and greater harm to plants, animals, and
marine ecosystems.
Question:
Oxygen Molecule.
Answer:
A naturally occurring diatomic form of the element that consists of two oxygen atoms bonded
together, making up about 21 percent of Earth's atmosphere and supporting breathing, combustion,
and many chemical reactions essential for life.
Question:
How is ozone formed?
Answer:
High energy ultraviolet radiation breaks apart ordinary oxygen gas into single oxygen atoms. These
free atoms then collide and bond with intact oxygen molecules, creating a three atom oxygen
structure in the upper atmosphere. This process happens continuously, especially in the stratosphere
where strong sunlight is present.
Question:
,Which layer of the atmosphere contains the most ozone?
Answer:
The stratosphere contains the greatest concentration of ozone, forming the primary protective layer
high above Earth.
Question:
What is ozone in the troposphere typically found as?
Answer:
Typically present as a harmful ground level pollutant, acting as a main component of smog created
from sunlight reacting with vehicle and industrial emissions.
Question:
Smog.
Answer:
A polluted atmospheric condition created when sunlight reacts with emissions from vehicles,
industry, and other sources, producing irritating and harmful gases and particles that reduce
visibility and negatively affect breathing, health, and the environment.
Question:
What are the two main types of ozone?
Answer:
Stratospheric ozone and tropospheric ozone.
Question:
Stratospheric Ozone.
Answer:
The naturally occurring protective concentration of ozone found high above Earth in the middle
atmospheric layer, where it absorbs and filters most of the Sun's harmful ultraviolet radiation,
helping protect human health, animals, and plant life.
, Question:
Tropospheric Ozone.
Answer:
A ground level form of ozone created mainly when sunlight reacts with emissions from vehicles,
industrial activities, and other pollution sources. It does not provide protection from ultraviolet
radiation and instead acts as an air pollutant that contributes to smog, irritates lungs, reduces
breathing ability, and harms plants and materials.
Question:
Hydrochlorofluorocarbons (HCFCs).
Answer:
Man made refrigerant chemicals that contain hydrogen, chlorine, fluorine, and carbon. They are less
damaging to the protective upper atmospheric layer than older chlorine based compounds because
hydrogen makes them break down sooner in the lower atmosphere. However, they still have ozone
depletion potential and contribute to global warming, so they are being phased out under
international and national environmental regulations.
Question:
When did scientists discover CFCs were destroying ozone?
Answer:
In the mid 1970s, especially after a 1974 scientific publication showed that chlorine from these
compounds could break down the protective upper atmospheric layer, leading to worldwide concern
and later confirmation in the 1980s.
Question:
Why are CFCs more harmful than HCFCs?
Answer:
Because they are extremely stable and do not break down in the lower atmosphere, they survive long
enough to reach the stratosphere where ultraviolet radiation releases chlorine that destroys large
amounts of the protective layer. They contain no hydrogen, so there is nothing to help them
PLUS
Question:
Ozone.
Answer:
A form of oxygen made of three bonded oxygen atoms that occurs naturally in the upper atmosphere
where it absorbs harmful ultraviolet radiation, while at ground level it can act as a pollutant that
irritates lungs and contributes to smog.
Question:
Where does ozone accumulate in the atmosphere?
Answer:
In the two lowest layers of Earth's atmosphere; between the stratosphere, and the troposphere. Most
of it is in the stratosphere, forming a concentrated layer high above Earth where it absorbs
ultraviolet radiation.
Question:
Chlorofluorocarbons (CFCs).
Answer:
Man-made chemical compounds composed of chlorine, fluorine, and carbon that were widely used
in refrigeration, air conditioning, aerosols, and foam production. They are extremely stable in the
lower atmosphere, allowing them to rise to the stratosphere where ultraviolet radiation breaks them
apart, releasing chlorine that destroys protective ozone. Their strong ozone depletion effect led to
global phaseout agreements such as the Montreal Protocol.
Question:
How do chlorofluorocarbons destroy ozone?
,Answer:
They rise into the upper atmosphere where strong ultraviolet radiation breaks them apart, releasing
chlorine atoms. These chlorine atoms react with ozone molecules, removing oxygen atoms and
turning them into ordinary oxygen. One chlorine atom can repeat this process many times, causing
significant thinning of the protective layer.
Question:
Why is the ozone layer important?
Answer:
It protects life on Earth by absorbing most of the Sun's harmful ultraviolet radiation before it reaches
the surface. Without this protective layer, increased UV exposure would raise risks of skin cancer,
eye damage like cataracts, weakened immune systems, and greater harm to plants, animals, and
marine ecosystems.
Question:
Oxygen Molecule.
Answer:
A naturally occurring diatomic form of the element that consists of two oxygen atoms bonded
together, making up about 21 percent of Earth's atmosphere and supporting breathing, combustion,
and many chemical reactions essential for life.
Question:
How is ozone formed?
Answer:
High energy ultraviolet radiation breaks apart ordinary oxygen gas into single oxygen atoms. These
free atoms then collide and bond with intact oxygen molecules, creating a three atom oxygen
structure in the upper atmosphere. This process happens continuously, especially in the stratosphere
where strong sunlight is present.
Question:
,Which layer of the atmosphere contains the most ozone?
Answer:
The stratosphere contains the greatest concentration of ozone, forming the primary protective layer
high above Earth.
Question:
What is ozone in the troposphere typically found as?
Answer:
Typically present as a harmful ground level pollutant, acting as a main component of smog created
from sunlight reacting with vehicle and industrial emissions.
Question:
Smog.
Answer:
A polluted atmospheric condition created when sunlight reacts with emissions from vehicles,
industry, and other sources, producing irritating and harmful gases and particles that reduce
visibility and negatively affect breathing, health, and the environment.
Question:
What are the two main types of ozone?
Answer:
Stratospheric ozone and tropospheric ozone.
Question:
Stratospheric Ozone.
Answer:
The naturally occurring protective concentration of ozone found high above Earth in the middle
atmospheric layer, where it absorbs and filters most of the Sun's harmful ultraviolet radiation,
helping protect human health, animals, and plant life.
, Question:
Tropospheric Ozone.
Answer:
A ground level form of ozone created mainly when sunlight reacts with emissions from vehicles,
industrial activities, and other pollution sources. It does not provide protection from ultraviolet
radiation and instead acts as an air pollutant that contributes to smog, irritates lungs, reduces
breathing ability, and harms plants and materials.
Question:
Hydrochlorofluorocarbons (HCFCs).
Answer:
Man made refrigerant chemicals that contain hydrogen, chlorine, fluorine, and carbon. They are less
damaging to the protective upper atmospheric layer than older chlorine based compounds because
hydrogen makes them break down sooner in the lower atmosphere. However, they still have ozone
depletion potential and contribute to global warming, so they are being phased out under
international and national environmental regulations.
Question:
When did scientists discover CFCs were destroying ozone?
Answer:
In the mid 1970s, especially after a 1974 scientific publication showed that chlorine from these
compounds could break down the protective upper atmospheric layer, leading to worldwide concern
and later confirmation in the 1980s.
Question:
Why are CFCs more harmful than HCFCs?
Answer:
Because they are extremely stable and do not break down in the lower atmosphere, they survive long
enough to reach the stratosphere where ultraviolet radiation releases chlorine that destroys large
amounts of the protective layer. They contain no hydrogen, so there is nothing to help them
