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A new survey of shooting stars has found that meteors that burn up at lower heights in the sky are more likely to leave a persistent afterglow. Previous assumptions that the speed or brightness of the meteor were the key variables were proven wrong. The afterglow is caused by a chemical reaction between metals burned off the meteor and oxygen in the atmosphere. The study also found that persistent trails can be left by meteors of all speeds and brightnesses, and the determining factor is the availability of ozone. [Extracted from the article]

Mixing the sun's ultraviolet radiation with those new chlorine compounds produces chlorine radicals, freewheeling molecules that attack ozone. Satellites had measured the abundance of certain chemicals in the stratosphere in 2020, including ozone, hydrogen chloride gas and chlorine nitrate. Over the next few decades, Solomon says, ozone recovery "is going to be sort of a race between CFCs getting destroyed and chlorine dropping and climate change getting worse and wildfires getting worse.". [Extracted from the article]

Others are likely "tied to private companies, recreation or research institutions studying weather or conducting other scientific research", President Joe Biden said February 16 in a news briefing. The project is called Boomerang and is designed to demonstrate the feasibility of using balloons for long-duration research. NOTEBOOK 50 YEARS AGO Scientists recovered for the first time … a balloon scientific payload after a long-duration, twice-around-the-world flight. [Extracted from the article]

The hole in the ozone layer had been on the mend, but the increasing frequency of large wildfires due to climate change threatens that recovery, the researchers say. EARTH & ENVIRONMENT Towers of smoke rose up into the stratosphere during Australia's "Black Summer" fires in 2019 and 2020 (as shown in New South Wales in December 2019). [Extracted from the article]

Part II. Discusses the climactic effects on Earth of solar variation. Effect of solar flares on satellites and the magnetic field surrounding Earth; Idea that solar variation drives Earths climate; Effect of the sun on the ozone layer of the atmosphere of Earth; Measurement of the 11-year variation of solar radiation using satellites.

Reports on the international agreement regarding the use of clorofluorocarbons which are used in refrigeration and foam production in the U.S. Substitution for the chemicals; Prevention on the destruction of ozone layer; Balance of a number of scientific, economic and geographic factors.

Comments on the finding by researchers of substantially less than normal ozone over much of the northern hemisphere during early 1993. Report from Rumen D. Bojkov of the United Nations' World Meteorological Organization in Geneva regarding concentrations of stratospheric ozone; View of Bojkov that certain chemicals caused much of the dramatic ozone thinning; Measurements made by the Upper Atmosphere Research Satellite (UARS); More.

Atmospheric pollutants have again left their mark in the skies over Antarctica as the 1991 ozone hole reached maturity. The atmospheric concentration of ozone dwindled to its lowest recorded level, according to satellite measurements. The dramatic ozone depletion marks the third year in a row that a severe ozone hole has developed over Antarctica, in contrast to the 1980s when major holes formed only in alternate years. The term ozone hole refers to a marked reduction in the number of stratospheric ozone molecules. Although winds from the north replenish the lost Antarctic ozone in November and December, the ozone hole's growth each year may be contributing to a general thinning of the global ozone layer, which satellite and ground-based instruments have detected over the past decade.

Investigates the responses of earth to energy outpourings of the sun. Transmission of radio signals along geo-magnetic field ionosphere and atmosphere; Role of satellites in the development of sun-earth link; Correlation between ionosphere and ozone layer.

Reports on the recommendation by the Federal Task Force on Inadvertent Modification of the Stratosphere to ban the use of fluorocarbons as propellants in aerosol spray cans by January 1978. Composition of the task force; Risks posed by fluorocarbon aerosol propellants and refrigerants to the earth's ozone layer; Effect of fluorocarbons 11 and 12 on ozone shield; Implications of ozone reduction for human health.

Reports that a Federal interagency task force has been organized in the U.S. to study the effects of aerosol propellants on the earth's protective ozone layer. Participating agencies in the task force; Theoretical mechanism for fluorochlorohydrocarbon behavior in the stratosphere proposed by atmospheric chemists; Functions of the task force.

Focuses on the detection of smoggy air, ozone pollution and other contaminants floating into the United States from Asia. How it was discovered by an airplane flying off the coast of Washington; How the pollution can cause respiratory distress and other health problems; Air quality of the Puget Sound; Condition of the ozone layer.

Reports findings which show a decrease in chlorine pollution in the Earth's stratosphere, indicating that ozone layer has started to heal itself from the effects of chlorofluorocarbons (CFCs) and other destructive compounds. History of CFC use; The effect of limiting CFC use; Outlook for the future.

Reports that the ozone hole that has developed in the stratosphere over Antarctica in 1999, has appeared to shrink. Size of the ozone hole; Decrease in the amount ozone-destroying compounds in the atmosphere aiding to the hole's shrinkage.

Looks at a scientific assessment made by NASA researchers which reports that the protective ozone layer over the United States and other populated regions of the Northern Hemisphere is thinning twice as fast as previously reported. New analyses of winter ozone values; Belief that chemical pollutants are causing the ozone depletions; Extension of the ozone thinning into springtime.

Reports that the hole in the Antarctic ozone layer has reached record proportions. This confirms the severe depletions that were predicted earlier this year.

Examines the depletion of the ring around the ozone hole in Antarctica. Series of high-altitude airplane flights for the study; Type of analysis conducted to detect ozone loss; Investigation of the stratospheric ozone concentrations.

Reports on the increase amount of ultraviolet radiation reaching Antarctica. Information on the ozone hole in the region's atmosphere; Effects of ultraviolet lights on biological communities; Slowing of photosynthesis by phytoplanktons caused by ultraviolet rays.

Reports on the implementation of an international treaty requiring the U.S. and other ratifying countries to freeze their production and consumption of certain chemicals that destroy the ozone. Prohibition on the use of chlorofluorocarbons; Mixture of chemicals by the chemists at Du Pont company; Threat of these chemicals to the ozone.

Assesses the status of Arctic stratospheric ozone. Correlation between low temperatures and polar stratospheric clouds; Composition of the clouds; Factors contributing to destruction of ozone layer.

Reports the enactment of an international law to protect the stratospheric ozone in the U.S. Reduction of the global chlorofluorocarbon emissions and freezing halon emissions; Schedule for the ratification of the treaty.

Reports on the research concerning the decline in ozone layer concentrations by scientists in the U.S. Destruction of stratospheric ozone by chlorine; Contribution of sulphuric acid and water to the ozone destruction; Heterogenous reactions due to the frozen cloud particles.

Focuses on the implications of high-energy electrons riding the earth's magnetic field lines for the malfunctions and failures of several satellites by scientists in Los Alamos, New Mexico. Role of the electrons in the loss of stratospheric ozone; Measurement of periodic fluxes of the electrons; Ionization of air molecules to produce nitrogen compounds.

Focuses on the efforts of the U.S. Environmental Agency in exploring the substitutes for chlorofluorocarbons. Effect of chlorofluorocarbons on the stratospheric zone; Use of chemical in refrigeration and foam insulation; Obstacles in the finding of chlorofluorocarbon substitute.

Discusses the role of chlorofluorocarbons in the seasonal depletion of Antarctic ozone. Levels of chlorine monoxide and nitrous oxide in the Antarctic stratosphere; Antarctic atmosphere models; Atmospheric chemistry.

Proposes the reduced production of some chemicals that attack stratospheric ozone. Chemicals responsible for the depletion of the stratospheric zone; Policies governing the control of hazardous chemicals; Controlled use of chlorofluorocarbons.

Reports on an analysis released by the U.S. Environmental Protection Agency on the destructive impact of the growth of global chlorofluorocarbon emissions on stratospheric ozone. Projections of increased incidence of skin cancers in the U.S. due to greater ultraviolet radiation reaching the earth; Effect of the increase of emissions on the environment.

Reports on the effects of forest fires on the atmosphere in Los Angeles, California. Destruction of the atmospheric ozone layer; Quantification of the production of nitrogen dioxide from burning biomass; Use of a laser-radar system to measure the particulates.

Reports the effect of chlorofluorocarbons (CFC) in the stratospheric ozone layer in the U.S. Emphasis on the conflict between CFC industries and government; Limitation of the future rate of halogenated CFC production; Negotiations on CFC controls.

Assesses the impact of deforestation on the stratospheric ozone layer. Contributions to global warming; Occurrence of climatic changes; Emissions of nitrogen oxide from clear-cut forest sites.

Focuses on the concerns of environmental scientists on the overabundance of smog in the ozone layer in the U.S. Failure of most population to meet the federal air quality standard for ozone; Effect of smog on the development of adverse respiratory diseases; Formation of ozone.

Focuses on the existence of scientific uncertainties in the depletion f the stratospheric ozone. Role of the ozone layer in shielding the earth of from biologically harmful ultraviolet radiation; Threats posed by human activities to the ozone and earth life; Development of ozone measurements from satellites.

Discusses the effects of chlorofluorocarbons and other chemicals on the ozone layer. Scientific history of the ozone; Explanation for the formation of hole in the ozone; Indicators of the declining ozone levels.

Reports on the detrimental effect to the ozone layer when polluters substitute highly reactive chemicals in place of the banned volatile organic chemicals (VOC). System of reward and punishment for limiting VOC use; Variations in VOC reactivity with cloud cover.

Examines some mysteries about the ozone layer. Questions about the best models for determining high-altitude ozone production and destruction; The ten percent difference between what models predict and what scientists actually observe; Views of Paul L. Houston and his colleagues; Report in the September 23, 1994 issue of `Science.'

Comments on a report from Australian researchers which states that algae living underneath the sea ice along the coast of Antarctica show little evidence of damage from the annual ozone hole. Study by Andrew McMinn and his colleagues; Report in the August 18, 1994 issue of `Nature.'

Looks at a challenge drawn by James B. Kerr and C. Thomas McElroy regarding the increase in total ultraviolet (UV) radiation in the Toronto area between 1989 and 1993. Reanalysis of the Kerr-McElroy winter data; Report in the May 27, 1994 issue of `Science.'

Looks at the views of some skeptics who do not believe that chlorofluorocarbons caused the ozone hole over Antarctica. The low ozone readings over Antarctica in 1958, when CFCs had not reached a dangerous level; Study by Paul A. Newman reported in the April 22, 1994 issue of `Science.'

Comments on the thinning of the global ozone layer. Measurements from the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus-7 showing that the ozone amounts in 1992 and early 1993 have been well below the lowest levels recorded during the last 13 years; Possible impact of Mt. Pinatubo; Report by James F. Gleason and his colleagues in the April 23, 1993 issue of `Science'; More.

Comments on a report by Terry Deshler and his colleagues that suggests that sulfur from a volcanic eruption in Chile may have helped chemical pollution create the most severe Antarctic ozone hole on record. History of ozone holes over the Antarctic; Possible impact of particles for Chile's Hudson Volcano; More.

States that a group of 80 researchers has concluded that the global ozone layer is even more vulnerable to chemical pollutants than previously thought. Comment of James G. Anderson of Harvard University, the project scientist for the study; Indications that chemical pollution destroyed significant amounts of ozone over the Arctic this winter; Measurements made by the ER-2 plane; Possible impact of the eruption of Mt. Pinatubo.

Reveals that balloon flights over Boulder, Colorado in December, 1991 measured the lowest December ozone values ever recorded at the site. The reading coincided with the passover of a patch of Mt. Pinatubo's volcanic cloud. Possible reflection of ozone destruction catalyzed by sulfuric acid particles in the cloud; Fall meeting of the American Geophysical Union; More.