EPA 608 UNIVERSAL CERTIFICATION
PREPARATION GUIDE
◉ 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.
◉ 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.
◉ 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.
,◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ What are the two main types of ozone?.
Answer: Stratospheric ozone and tropospheric ozone.
◉ 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.
◉ 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.
◉ 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.
◉ 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
PREPARATION GUIDE
◉ 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.
◉ 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.
◉ 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.
,◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ 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.
◉ What are the two main types of ozone?.
Answer: Stratospheric ozone and tropospheric ozone.
◉ 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.
◉ 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.
◉ 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.
◉ 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
