Wiki

Resources

Climate
Links

Impacts
of Climate Change

Educational
Links

Energy
Links

International
Links

Green
Campus

Archives

Publications

Climate
Alert

Islands
Program Newsletter

25th Anniversary Report

Climate Institute Brochure

Strategic Plan
2008-2013

Other
Publications

Articles by
Topic

Topics

Climate
Change

Sea Level
Rise

Extreme
Weather

Ecosystems
& Wildlife

Air
Quality

Ozone
Depletion

Human
Health

Agriculture

Water

Environment
& Security

Energy

Domestic
Action

International
Action

How You Can
Help

Programs

Mexico
& Latin American Programs

Islands
Programs

GSEII

Endangered
Islands Campaign

Black
Carbon Reduction Program

Tribal
College Climate Protection Program

Climate
Capacity Initiative for Financial Institutions

Education
& Outreach Program

About
Us

Mission

History

Staff

Board of
Directors

Board of
Advisors

Donors &
Partners

Internships

Internship
Description

Qualifications

Dates &
Deadlines

How to
Apply

Contact Us

Donate

Home

TOPICS / CORE ISSUES

Climate
Change

Sea Level
Rise

Extreme
Weather

Ecosystems
& Wildlife

Air
Quality

Ozone
Depletion

Human Health

Agriculture

Water

Environment
and  Security

Energy

Domestic
Action

International
Action

How You Can
Help

Español
中文
Deutsch
Italiano
বাংলা
OZONE DEPLETION

Ozone is a particular gas present both in the Earth's upper atmosphere and at
ground level. There are two distinct types of ozone; the Ground-level Ozone (or
“bad” ozone) and the Stratospheric Ozone (or “good” ozone layer)

Ground-level Ozone (GOL) is located in the troposphere,
close to the Earth's surface. It is the main ingredient of urban smog that
originates in emissions from industrial facilities and electric utilities, motor
vehicle exhaust, gasoline vapors, and chemical solvents. Ground level ozone is
created by chemical reactions between oxides of nitrogen (NOx) and volatile
organic compounds (VOC) in the presence of sunlight. Ground-level ozone is a
harmful pollutant for humans. Breathing ozone can trigger a variety of health
problems including chest pain, coughing, throat irritation, and congestion or it
can worsen bronchitis, emphysema, and asthma. Another aspect of the GLO is its
detrimental effect on the ecosystem as it can damage crops, trees and other
vegetation. It is responsible for an estimated $500 million in reduced crop
production each year in the United States.

The 1963 Clean
Air Act (CAA) has set protective health-based standards for ozone.
Amended several times since its creation, the CAA mandates the ongoing
promulgation of a variety of emission standards and controls. Its primary
objective is to establish Federal standards for various pollutants from both
stationary and mobile sources and to provide for the regulation of polluting
emissions via state implementation plans. In addition, the amendments are
designed to prevent significant deterioration in certain areas where air quality
exceeds national standards, and to provide for improved air quality in areas
that do not meet Federal standards (referred to as "nonattainment" areas). The
Environmental Protection Agency (EPA) and others organisms have also contributed
to a variety of multi-faceted programs to meet health-based standards.

Figure 1: Location of the 2 ozone layers (EPA website)

Naturally produced in the stratosphere (extending upward from about 6 to 30
miles from the earth surface), the stratospheric ozone is a
layer in the Earth atmosphere comparable to a natural shield protecting life on
earth. This ozone absorbs between 97 to 99% of the sun’s harmful ultra-violet
(UV) rays thus protecting life on earth. However, this "good" ozone is gradually
being depleted by chemicals referred to as ozone-depleting substances (ODS),
including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons,
methyl bromide, carbon tetrachloride, and methyl chloroform. These man-made
chemicals are ultimately responsible for more cases of skin cancer, cataracts,
and other health problems.

In 1974 Mexican researcher Mario J. Molina and American F. S. Rowland
published a laboratory study demonstrating the ability of CFC's to breakdown
Ozone in the presence of high frequency UV light.

In 1985, atmospheric scientists highlighted the tremendous consequences of
ozone-depleting substances for the ozone layer by pointing out the discovery of
a “hole” in the upper atmosphere (stratosphere) over Antarctica.

Further studies estimated that the ozone layer would be depleted by CFC's by
about 7% within 60 years.  These incidents were soon followed by the
signature by the US and 180 countries of the
Montreal Protocol on Substances That Deplete the Ozone
Layer, an international treaty designed to phase out the production
of a number of substances believed to be responsible for ozone depletion. The
treaty was opened for signature on September 16, 1987 and entered into force on
January 1, 1989 and has been hailed as an example of international cooperation.

Figure2: Total reported global production of ozone
depleting substances (ods). (2007). In UNEP/GRID-Arendal Maps and Graphics
Library. Retrieved 17:03, March 26, 2008 from http://maps.grida.no/go/graphic/total-reported-global-production-of-ozone-depleting-substances

Since the adoption and strengthening of the Montreal Protocol has led to
reductions in the emissions of CFCs, atmospheric concentrations of the most
significant compounds have been declining. These substances are being gradually
removed from the atmosphere. A complete recovery of the Antarctic ozone layer
will not occur until the year 2050 or later. Although many countries have
diligently complied with the Montreal Protocol allowing a drastic reduction of
ozone depleting substances (see graph above),  stockpiled, recycled and
illegally traded CFCs, together with those in refrigeration and fire-fighting
equipment, will still be around for many years.

While industrialized countries have agreed to phase out halocarbons, some
critical uses are exempt and developing countries have been given longer
time-scales.

Additional Resources:

Ozone depletion and climate change. (2007). In
UNEP/GRID-Arendal Maps and Graphics Library. Retrieved 15:43, March 26,
2008 from http://maps.grida.no/go/graphic/ozone-depletion-and-climate-change
(PDF
file)

Join the Climate Institute
e-news mailing list:

© 2007 -
2010
Climate Institute
All Rights Reserved

900 17th St. NW,
Suite 700, Washington, DC 20006
Phone: +1-202-552-4723
Fax:
+1-202-737-6410
[email-masked]