Trends in Emissions of Ozone-Depleting Substances, Ozone Layer Recovery, and Implications for Ultraviolet Radiation Exposure

Trends in Emissions of Ozone-Depleting Substances, Ozone Layer Recovery, and Implications for Ultraviolet Radiation Exposure

Date: November 2008
Creator: US Climate Change Science Program and the Subcommittee on Global Change Research.
Description: This Synthesis and Assessment Product (SAP 2.4) focuses on the Climate models. Depletion of the stratospheric ozone layer by human-produced ozone-depleting substances has been recognized as a global environmental issue for more than three decades, and the international effort to address the issue via the United Nations Montreal Protocol marked its 20-year anniversary in 2007. Scientific understanding underpinned the Protocol at its inception and ever since. As scientific knowledge advanced and evolved, the Protocol evolved through amendment and adjustment. Policy-relevant science has documented the rise, and now the beginning decline, of the atmospheric abundances of many ozone-depleting substances in response to actions taken by the nations of the world. Projections are for a return of ozone-depleting chemicals (compounds containing chlorine and bromine) to their "pre-ozone-depletion" (pre-1980) levels by the middle of this century for the midlatitudes; the polar regions are expected to follow suit within 20 years after that. Since the 1980s, global ozone sustained a depletion of about 5 percent in the midlatitudes of both the Northern Hemisphere and Southern Hemisphere, where most of the Earth's population resides; it is now showing signs of turning the corner towards increasing ozone. The large seasonal depletions in the polar regions are ...
Contributing Partner: UNT Libraries
IPCC Special Report Aviation and the Global Atmosphere: Summary for Policymakers

IPCC Special Report Aviation and the Global Atmosphere: Summary for Policymakers

Date: 1999
Creator: Intergovernmental Panel on Climate Change (IPCC) Working Groups I and III
Description: The Intergovernmental Panel on Climate Change (IPCC) was jointly established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) in 1988 to: (i) assess available information on the science, the impacts, and the economics of, and the options for mitigating and/or adapting to, climate change and (ii) provide, on request, scientific/technical/socio-economic advice to the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC). Since then the IPCC has produced a series of Assessment Reports, Special Reports, Technical Papers, methodologies, and other products that have become standard works of reference, widely used by policymakers, scientists, and other experts. This Special Report was prepared following a request from the International Civil Aviation Organization (ICAO) and the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer. The state of understanding of the relevant science of the atmosphere, aviation technology, and socio-economic issues associated with mitigation options is assessed and reported for both subsonic and supersonic fleets. The potential effects that aviation has had in the past and may have in the future on both stratospheric ozone depletion and global climate change are covered; environmental impacts of aviation at the local ...
Contributing Partner: UNT Libraries
Highways of a Global Traveler: Tracking Tropospheric Ozone

Highways of a Global Traveler: Tracking Tropospheric Ozone

Date: March 22, 2002
Creator: Allen, Jeannie
Description: On the stage of global change, ozone plays the role of both hero and villain. This brief document discusses about the tracking of Tropospheric Ozone, where ozone forms and where it travels have become key concerns for international health and economic policy-making.
Contributing Partner: UNT Libraries
Anthropogenic Ozone Depletion: Status and Human Health Implications, USGCRP Seminar, 13 November 1995.

Anthropogenic Ozone Depletion: Status and Human Health Implications, USGCRP Seminar, 13 November 1995.

Date: November 13, 1995
Creator: Albritton, Daniel
Description: In this USGRP Seminar, speakers answer the following questions: what is the status of the Earth's ozone layer? Is the Montreal Protocol working? How much time will be necessary for nature to restore the ozone layer? What are the human health effects of increased ultraviolet radiation associated with depletion of the ozone layer? Who is at risk?
Contributing Partner: UNT Libraries
Air Quality and the New Ozone NAAQS: The OTAG Process

Air Quality and the New Ozone NAAQS: The OTAG Process

Date: July 30, 1998
Creator: Parker, Larry
Description: The Ozone Transport Assessment Group (OTAG) represented a cooperative effort between states, the Environmental Protection Agency (EPA), and numerous stakeholders to address teh complex issue of ozone transport. However, opponents of the new ozone National Ambient Air Quality Standard (NAAQS) argue that the OTAG recommendations are far too vague and ambiguous to be cited by EPA as a basis for implementation. This report provides background on the effort, and summarizes OTAG's assessment and recommendations.
Contributing Partner: UNT Libraries Government Documents Department
Measuring Atmospheric Ozone and Nitrogen Dioxide Concentration by Differential Optical Absorption Spectroscopy

Measuring Atmospheric Ozone and Nitrogen Dioxide Concentration by Differential Optical Absorption Spectroscopy

Access: Use of this item is restricted to the UNT Community.
Date: December 2011
Creator: Jerez, Carlos J.
Description: The main objective was to develop a procedure based on differential optical absorption spectroscopy (DOAS) to measure atmospheric total column of ozone, using the automated instrument developed at the University of North Texas (UNT) by Nebgen in 2006. This project also explored the ability of this instrument to provide measurements of atmospheric total column nitrogen dioxide. The instrument is located on top of UNT’s Environmental Education, Science and Technology Building. It employs a low cost spectrometer coupled with fiber optics, which are aimed at the sun to collect solar radiation. Measurements taken throughout the day with this instrument exhibited a large variability. The DOAS procedure derives total column ozone from the analysis of daily DOAS Langley plots. This plot relates the measured differential column to the airmass factor. The use of such plots is conditioned by the time the concentration of ozone remains constant. Observations of ozone are typically conducted throughout the day. Observations of total column ozone were conducted for 5 months. Values were derived from both DOAS and Nebgen’s procedure and compared to satellite data. Although differences observed from both procedures to satellite data were similar, the variability found in measurements was reduced from 70 Dobson units, with ...
Contributing Partner: UNT Libraries