The Science of Ozone Depletion

Ozone depletion is the result of a complex set of circumstances and chemistry. This page has links to articles that give overviews or broad information, shorter pieces that focus on specific aspects of ozone depletion, images and animations of ozone levels and ozone depletion, and international organizations that issue regular updates.

Please note that this site is intended only to provide general information about the science of ozone depletion. Therefore, it is written without detailed citations of original research. If you need such references, please see either the answers to frequently asked questions, by Robert Parson, or NASA's Ozone Resource File , both of which provide detailed information and full citations to original papers. You can also find many original papers at the CIESIN site .

EPA has another web site about global warming. Please visit that site for information on global warming science, projected impacts, governmental policies, and other information.

General Information

Forecast Earth

Two minute movies summarizing the science and effects of ozone depletion created through a partnership between EPA and The Weather Channel.

Scientific Assessment of Ozone Depletion: 2002

This is the most recent World Meteorological Organization and United Nations Environmental Programme assessment. It contains the most up-to-date understanding of ozone depletion and reflects the thinking of over 250 international scientific experts who contributed to its preparation and review.
Alternate Link: UNEP site

Twenty Questions and Answers About Ozone Depletion (2.1 MB)

This component of the "Scientific Assesment of Ozone Depletion: 2002" presents 20 questions and answers about the often-complex science of ozone depletion. The answers were all prepared by and reviewed by a large international group of scientists. It is written for a broad readership of decision-makers, educators, students, and the
general public.

Questions and Answers (brief)

Fact Sheet (detailed)

What EPA Has Done About Ozone Depletion: An Overview

What Can Individuals Do?

On the Trail of the Missing Ozone

This introduction to ozone depletion first describes the causes and effects of ozone depletion, and then explains some of the solutions. Follow Farley the reporter as he learns about this issue. Links are provided along the way to more detailed information found elsewhere on the site. Three versions are available: a web-viewable set of illustrated panels, a text version, and an Adobe Acrobat version.

The Ozone Depletion Process

A broad overview of how ozone depletion occurs.

The Antarctic Ozone Hole

View an animation of the 2000 hole, read why it occurs over the South Pole, and consider the many ways to measure the hole.

Current Progress of the Antarctic Ozone Hole

View a page from NOAA Climate Prediction Center's web site, which shows weekly updates of the hole.

Ozone Science Crossword Puzzle

Environmental Indicators: Ozone Depletion

Describes the data that characterize the ozone layer and demonstrate that CFCs and other chemicals are causing ozone depletion. Many internal links allow more in-depth reading.

Ozone Depletion: When Less Is Not Enough

Written by the National Safety Council's Environmental Health Center, this guide provides a well-rounded description of ozone depletion, its causes, and its impacts. It is one chapter of a book titled Reporting on Climate Change: Understanding the Science.

Ozone-Depleting Substances, ODPs, GWPs, and CAS Numbers

Myth vs. Measurement

A series of responses to the most common misunderstandings about ozone depletion.

• CFCs are Heavier Than Air, So They Can't Reach the Ozone Layer
• Volcanoes and the Oceans are Causing Ozone Depletion
• Ozone Depletion Occurs Only In Antarctica
• No Link Exists Between Ozone Depletion and Higher UV Levels

Will the Ozone Layer Recover? Can We Make More Ozone?

A response to common questions about the ozone layer's recovery.

The Effects of Ozone Depletion

A basic description of how ozone depletion harms human health and the environment, with links to more detailed information.

Benefits of the CFC Phaseout

This fact sheet describes specific benefits and also includes some case studies of successful use of alternatives.

Ozone: Good Up High, Bad Nearby

Produced by EPA's Office of Air Quality Planning and Standards, this fact sheet explains the difference between stratospheric and tropospheric ozone.

Information from Environment Canada

The Stratospheric Ozone web site contains general and Canadian-focused information on ozone depletion including a primer on ozone depletion and indicators of ozone depletion, featuring many graphs and original data.

Stratospheric Ozone Depletion: A Focus on EPA's Research

This brochure describes the mechanisms of and problems associated with stratospheric ozone depletion as well as some of the research projects pursued by EPA's Office of Research and Development (ORD).

Specific Aspects of Ozone Depletion

Numbering Scheme for Ozone-Depleting Substances and Substitutes

Why chemicals are numbered certain ways.

Ozone vs. Altitude

Ozone concentrations are higher in the stratosphere than in the troposphere.

Aerosols from Mt. Pinatubo

A graph and explanation of the effects of volcanic aerosols on ozone depletion.

Ozone Depletion Over the Northern Hemisphere

Compares Arctic and Antarctic ozone losses, along with ozone changes over North America and Arosa, Switzerland.

University of Georgia UV Monitoring

Information on the network of UV monitors operated for EPA.

Images and Animations

Animation of the 2003 Ozone Hole

A brief description of the causes of the ozone hole, plus an animation of the 2003 event.

EPA's Ultraviolet Monitoring Program

EPA operates and maintains a network of Brewer spectrophotometers throughout the United States, measuring full-sky spectrally-resolved solar radiation in the UV-B and UV-A bands. Visitors can create graphs of daily UV and ozone levels and download the data.

NASA's TOMS (Total Ozone Mapping Spectrometer) Multimedia Files: Ozone Depletion Movies, Graphics, and Original Data

This site is full of useful data and information. Download original ozone level data and see movies and graphics of ozone depletion and the Antarctic ozone hole. The site also lets you find the ozone level over your house!

NOAA Climate Monitoring and Diagnostics Laboratory

CMDL includes several programs to measure important atmospheric characteristics.

Nitrous Oxide And Halocompounds (NOAH) division

NOAH measures concentrations of CFCs and other ozone-depleting substances in the atmosphere. The web site provides access to data and graphs.

Ozone and Water Vapor Group

Provides links to several programs focusing on ozone measurement, including vertical profiles of ozone abundance at the South Pole during the occurrence of the ozone hole and total global ozone.

NOAA Climate Prediction Center

Includes current satellite ozone maps; UV index bulletin; TOVS data, images.

Ozone Hole Tour

This tour was put together by members of the Centre for Atmospheric Science at the University of Cambridge, UK. It features text, graphics, and movies.

Ozone Images from the Department of Meteorology, University of Reading, UK

Features a 90-day archive of the latest images from global, northern hemisphere, and southern hemisphere ozone measurements. Also features animations and ozonesonde measurements from Antarctica. Some of these images are also available from the NOAA Climate Prediction Center.

World Ozone and Ultraviolet Radiation Data Centre

Operated by Environment Canada, this Centre provides current and time series graphs of ozone and UV radiation over Canada and North America.

International Scientific Organizations

World Meteorological Organization Press Releases and Bulletins

A collection of recent bulletins about the ozone hole.

British Antarctic Survey information

Information from the group responsible for monitoring the Antarctic Ozone Hole, including regular bulletins on ozone levels.

Online papers at CIESIN

This site provides the full text of an enormous number of papers on ozone depletion.

Ozone Science Frequently Asked Questions (FAQ), Answers, and References (not maintained by EPA; thanks to Robert Parson)

Links to Other Information