3.1.4 Ozone
Ozone is the triatomic form of oxygen (O 3 ). It is a gaseous atmospheric constituent.
In the troposphere, it is created by photochemical reactions involving gases resulting
both from natural sources and from human activities (photochemical smog). In high
concentrations, tropospheric ozone can be harmful to a wide range of living organisms. Ozone is a bluish gas that is harmful to breathe. Tropospheric ozone acts as a
greenhouse gas. Nearly 90% of the earth’s ozone is in the stratosphere and is referred
to as the ozone layer. In the stratosphere, ozone is created by the interaction between
solar ultraviolet radiation and molecular oxygen (O 2 ). Stratospheric ozone plays a
decisive role in the stratospheric radiative balance. Since ozone absorbs a band of
ultraviolet radiation called UVB that is particularly harmful to living organisms, the
ozone layer prevents most UVB from reaching the ground. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by climate change,
results in an increased ground-level flux of ultraviolet (UV-) B radiation.
Ozone “Hole” is a large area of the stratosphere with extremely low amounts of
ozone.
Ozone-depleting substance (ODS) is a family of man-made compounds that
include, but are not limited to, chlorofluorocarbons (CFCs), bromofluorocarbons
(halons), methyl chloroform, carbon tetrachloride, methyl bromide, and
hydrochlorofluorocarbons (HCFCs). These compounds have been shown to deplete
stratospheric ozone and therefore are typically referred to as ODSs.
Ozone layer depletion is a chemical reaction involving destruction of ozone
molecules in the ozone layer. Depletion of this ozone layer by ozone-depleting
substances will lead to higher UVB levels (a band of ultraviolet radiation), which
in turn will cause increased skin cancers and cataracts and potential damage to some
marine organisms, plants, and plastics.
3.1.5 Fluorinated Gases
Fluorinated gases are very powerful synthetic greenhouse gases such as
hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride that are emitted
from a variety of industrial processes. Fluorinated gases are sometimes used as
substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons,
hydrochlorofluorocarbons, and halons) and are often used in coolants, foaming
agents, fire extinguishers, solvents, pesticides, and aerosol propellants. These
gases are emitted in small quantities compared to carbon dioxide (CO2), methane
(CH 4 ), or nitrous oxide (N 2 O), but because they are potent greenhouse gases, they
are sometimes referred to as high global warming potential gases (high GWP gases).
Fluorocarbons are carbon-fluorine compounds that often contain other elements
such as hydrogen, chlorine, or bromine. Common fluorocarbons include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons
(HFCs), and perfluorocarbons (PFCs).
1 Effect of Global Warming and Climate Change on Glaciers and Salmons
7
Ozone is the triatomic form of oxygen (O 3 ). It is a gaseous atmospheric constituent.
In the troposphere, it is created by photochemical reactions involving gases resulting
both from natural sources and from human activities (photochemical smog). In high
concentrations, tropospheric ozone can be harmful to a wide range of living organisms. Ozone is a bluish gas that is harmful to breathe. Tropospheric ozone acts as a
greenhouse gas. Nearly 90% of the earth’s ozone is in the stratosphere and is referred
to as the ozone layer. In the stratosphere, ozone is created by the interaction between
solar ultraviolet radiation and molecular oxygen (O 2 ). Stratospheric ozone plays a
decisive role in the stratospheric radiative balance. Since ozone absorbs a band of
ultraviolet radiation called UVB that is particularly harmful to living organisms, the
ozone layer prevents most UVB from reaching the ground. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by climate change,
results in an increased ground-level flux of ultraviolet (UV-) B radiation.
Ozone “Hole” is a large area of the stratosphere with extremely low amounts of
ozone.
Ozone-depleting substance (ODS) is a family of man-made compounds that
include, but are not limited to, chlorofluorocarbons (CFCs), bromofluorocarbons
(halons), methyl chloroform, carbon tetrachloride, methyl bromide, and
hydrochlorofluorocarbons (HCFCs). These compounds have been shown to deplete
stratospheric ozone and therefore are typically referred to as ODSs.
Ozone layer depletion is a chemical reaction involving destruction of ozone
molecules in the ozone layer. Depletion of this ozone layer by ozone-depleting
substances will lead to higher UVB levels (a band of ultraviolet radiation), which
in turn will cause increased skin cancers and cataracts and potential damage to some
marine organisms, plants, and plastics.
3.1.5 Fluorinated Gases
Fluorinated gases are very powerful synthetic greenhouse gases such as
hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride that are emitted
from a variety of industrial processes. Fluorinated gases are sometimes used as
substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons,
hydrochlorofluorocarbons, and halons) and are often used in coolants, foaming
agents, fire extinguishers, solvents, pesticides, and aerosol propellants. These
gases are emitted in small quantities compared to carbon dioxide (CO2), methane
(CH 4 ), or nitrous oxide (N 2 O), but because they are potent greenhouse gases, they
are sometimes referred to as high global warming potential gases (high GWP gases).
Fluorocarbons are carbon-fluorine compounds that often contain other elements
such as hydrogen, chlorine, or bromine. Common fluorocarbons include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons
(HFCs), and perfluorocarbons (PFCs).
1 Effect of Global Warming and Climate Change on Glaciers and Salmons
7