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1
Srivani, Alla. "Effect of Ozone Layer Depletion on Advanced Materials." Radiology Research and Diagnostic Imaging 2, no. 1 (February 9, 2023): 01–03. http://dx.doi.org/10.58489/2836-5127/010.
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From ozone exposure can result in significant economic losses due to the higher costs of maintenance, upkeep, and replacement of these materials. Common plastic materials' outdoor service life is restricted by their vulnerability to sun UV radiation. The UV-B component of the solar spectrum is highly effective in causing photo damage in manufactured and naturally occurring materials. This is especially true with plastics, rubber, and wood utilised in the construction and agriculture industries. Any drop in the stratospheric ozone layer and resulting increase in the UV-B component of terrestrial sunlight will therefore tend to reduce the service life of these materials. However, estimating the extent to which the service life is shortened is challenging because it is dependent on various factors.
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De Winter-Sorkina, Renata. "Impact of ozone layer depletion I: ozone depletion climatology." Atmospheric Environment 35, no. 9 (March 2001): 1609–14. http://dx.doi.org/10.1016/s1352-2310(00)00436-2.
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Rowland, F. Sherwood. "Stratospheric ozone depletion." Philosophical Transactions of the Royal Society B: Biological Sciences 361, no. 1469 (February 21, 2006): 769–90. http://dx.doi.org/10.1098/rstb.2005.1783.
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Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO 2 , NO, NO 2 , Cl and ClO. The NO X and ClO X chains involve the emission at Earth's surface of stable molecules in very low concentration (N 2 O, CCl 2 F 2 , CCl 3 F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.
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Lu, Jinpeng, Fei Xie, Hongying Tian, and Jiali Luo. "Impacts of Ozone Changes in the Tropopause Layer on Stratospheric Water Vapor." Atmosphere 12, no. 3 (February 24, 2021): 291. http://dx.doi.org/10.3390/atmos12030291.
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Stratospheric water vapor (SWV) changes play an important role in regulating global climate change, and its variations are controlled by tropopause temperature. This study estimates the impacts of tropopause layer ozone changes on tropopause temperature by radiative process and further influences on lower stratospheric water vapor (LSWV) using the Whole Atmosphere Community Climate Model (WACCM4). It is found that a 10% depletion in global (mid-low and polar latitudes) tropopause layer ozone causes a significant cooling of the tropical cold-point tropopause with a maximum cooling of 0.3 K, and a corresponding reduction in LSWV with a maximum value of 0.06 ppmv. The depletion of tropopause layer ozone at mid-low latitudes results in cooling of the tropical cold-point tropopause by radiative processes and a corresponding LSWV reduction. However, the effect of polar tropopause layer ozone depletion on tropical cold-point tropopause temperature and LSWV is opposite to and weaker than the effect of tropopause layer ozone depletion at mid-low latitudes. Finally, the joint effect of tropopause layer ozone depletion (at mid-low and polar latitudes) causes a negative cold-point tropopause temperature and a decreased tropical LSWV. Conversely, the impact of a 10% increase in global tropopause layer ozone on LSWV is exactly the opposite of the impact of ozone depletion. After 2000, tropopause layer ozone decreased at mid-low latitudes and increased at high latitudes. These tropopause layer ozone changes at different latitudes cause joint cooling in the tropical cold-point tropopause and a reduction in LSWV. Clarifying the impacts of tropopause layer ozone changes on LSWV clearly is important for understanding and predicting SWV changes in the context of future global ozone recovery.
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De Winter-Sorkina, Renata. "Impact of ozone layer depletion II:." Atmospheric Environment 35, no. 9 (March 2001): 1615–25. http://dx.doi.org/10.1016/s1352-2310(00)00437-4.
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Rowlands, Ian H. "OZONE LAYER DEPLETION AND GLOBAL WARMING." Peace & Change 16, no. 3 (July 1991): 260–84. http://dx.doi.org/10.1111/j.1468-0130.1991.tb00572.x.
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Christidou, Vasilia, and Vasilis Koulaidis. "Children's models of the ozone layer and ozone depletion." Research in Science Education 26, no. 4 (December 1996): 421–36. http://dx.doi.org/10.1007/bf02357453.
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Lehrer, E., G. Hönninger, and U. Platt. "The mechanism of halogen liberation in the polar troposphere." Atmospheric Chemistry and Physics Discussions 4, no. 3 (June 28, 2004): 3607–52. http://dx.doi.org/10.5194/acpd-4-3607-2004.
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Abstract. Sudden depletions of tropospheric ozone during spring were reported from the Arctic and also from Antarctic coastal sites. Field studies showed that those depletion events are caused by reactive halogen species, especially bromine compounds. However the source and seasonal variation of reactive halogen species is still not completely understood. There are several indications that the halogen mobilisation from the sea ice surface of the polar oceans may be the most important source for the necessary halogens. Here we present a 1-D model study aimed at determining the primary source of reactive halogens. The model includes gas phase and heterogeneous bromine and chlorine chemistry as well as vertical transport between the surface and the top of the boundary layer. The autocatalytic Br release by photochemical processes (bromine explosion) and subsequent rapid bromine catalysed ozone depletion is well reproduced in the model and the major source of reactive bromine appears to be the sea ice surface. The sea salt aerosol alone is not sufficient to yield the high levels of reactive bromine in the gas phase necessary for fast ozone depletion. However, the aerosol efficiently 'recycles' less reactive bromine species (e.g. HBr) and feeds them back into the ozone destruction cycle. Isolation of the boundary layer air from the free troposphere by a strong temperature inversion was found to be critical for boundary layer ozone depletion to happen. The combination of strong surface inversions and presence of sunlight occurs only during polar spring.
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Lehrer, E., G. Hönninger, and U. Platt. "A one dimensional model study of the mechanism of halogen liberation and vertical transport in the polar troposphere." Atmospheric Chemistry and Physics 4, no. 11/12 (December 6, 2004): 2427–40. http://dx.doi.org/10.5194/acp-4-2427-2004.
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Abstract. Sudden depletions of tropospheric ozone during spring were reported from the Arctic and also from Antarctic coastal sites. Field studies showed that those depletion events are caused by reactive halogen species, especially bromine compounds. However the source and seasonal variation of reactive halogen species is still not completely understood. There are several indications that the halogen mobilisation from the sea ice surface of the polar oceans may be the most important source for the necessary halogens. Here we present a one dimensional model study aimed at determining the primary source of reactive halogens. The model includes gas phase and heterogeneous bromine and chlorine chemistry as well as vertical transport between the surface and the top of the boundary layer. The autocatalytic Br release by photochemical processes (bromine explosion) and subsequent rapid bromine catalysed ozone depletion is well reproduced in the model and the major source of reactive bromine appears to be the sea ice surface. The sea salt aerosol alone is not sufficient to yield the high levels of reactive bromine in the gas phase necessary for fast ozone depletion. However, the aerosol efficiently "recycles" less reactive bromine species (e.g. HBr) and feeds them back into the ozone destruction cycle. Isolation of the boundary layer air from the free troposphere by a strong temperature inversion was found to be critical for boundary layer ozone depletion to happen. The combination of strong surface inversions and presence of sunlight occurs only during polar spring.
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Zhao, Xiaoyi, Dan Weaver, Kristof Bognar, Gloria Manney, Luis Millán, Xin Yang, Edwin Eloranta, Matthias Schneider, and Kimberly Strong. "Cyclone-induced surface ozone and HDO depletion in the Arctic." Atmospheric Chemistry and Physics 17, no. 24 (December 19, 2017): 14955–74. http://dx.doi.org/10.5194/acp-17-14955-2017.
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Abstract. Ground-based, satellite, and reanalysis datasets were used to identify two similar cyclone-induced surface ozone depletion events at Eureka, Canada (80.1° N, 86.4° W), in March 2007 and April 2011. These two events were coincident with observations of hydrogen deuterium oxide (HDO) depletion, indicating that condensation and sublimation occurred during the transport of the ozone-depleted air masses. Ice clouds (vapour and crystals) and aerosols were detected by lidar and radar when the ozone- and HDO-depleted air masses arrived over Eureka. For the 2007 event, an ice cloud layer was coincident with an aloft ozone depletion layer at 870 m altitude on 2–3 March, indicating this ice cloud layer contained bromine-enriched blowing-snow particles. Over the following 3 days, a shallow surface ozone depletion event (ODE) was observed at Eureka after the precipitation of bromine-enriched particles onto the local snowpack. A chemistry–climate model (UKCA) and a chemical transport model (pTOMCAT) were used to simulate the surface ozone depletion events. Incorporating the latest surface snow salinity data obtained for the Weddell Sea into the models resulted in improved agreement between the modelled and measured BrO concentrations above Eureka. MERRA-2 global reanalysis data and the FLEXPART particle dispersion model were used to study the link between the ozone and HDO depletion. In general, the modelled ozone and BrO showed good agreement with the ground-based observations; however, the modelled BrO and ozone in the near-surface layer are quite sensitive to the snow salinity. HDO depletion observed during these two blowing-snow ODEs was found to be weaker than pure Rayleigh fractionation. This work provides evidence of a blowing-snow sublimation process, which is a key step in producing bromine-enriched sea-salt aerosol.
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IBUSUKI, Takashi. "Depletion of Stratospheric Ozone Layer by Chlorofluorocarbons." Journal of Japan Oil Chemists' Society 41, no. 9 (1992): 867–71. http://dx.doi.org/10.5650/jos1956.41.867.
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Mickle, R. E., J. W. Bottenheim, W. R. Leaitch, and W. Evans. "Boundary layer ozone depletion during AGASP-II." Atmospheric Environment (1967) 23, no. 11 (January 1989): 2443–49. http://dx.doi.org/10.1016/0004-6981(89)90255-2.
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Chipperfield, Martyn P., and Slimane Bekki. "Opinion: Stratospheric ozone – depletion, recovery and new challenges." Atmospheric Chemistry and Physics 24, no. 4 (March 1, 2024): 2783–802. http://dx.doi.org/10.5194/acp-24-2783-2024.
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Abstract. We summarise current important and well-established open issues related to the depletion of stratospheric ozone and discuss some newly emerging challenges. The ozone layer is recovering from the effects of halogenated source gases due to the continued success of the Montreal Protocol despite recent renewed production of controlled substances and the impact of uncontrolled very short-lived substances. The increasing atmospheric concentrations of greenhouse gases, such as carbon dioxide, methane (CH4) and nitrous oxide (N2O), have large potential to perturb stratospheric ozone in different ways, but their future evolutions, and hence impacts, are uncertain. Ozone depletion through injection of smoke particles has been observed following recent Australian wildfires. Further perturbations to the ozone layer are currently occurring through the unexpected injection of massive amounts of water vapour from the Hunga Tonga–Hunga Ha'apai volcano in 2022. Open research questions emphasise the critical need to maintain, if not expand, the observational network and to address the impending “satellite data gap” in global, height-resolved observations of stratospheric trace gases and aerosols. We will, in effect, be largely blind to the stratospheric effects of similar wildfire and volcanic events in the near future. Complex Earth system models (ESMs) being developed for climate projections have the stratosphere as an important component. However, the huge computational requirement of these models must not result in an oversimplification of the many processes affecting the ozone layer. Regardless, a hierarchy of simpler process models will continue to be important for testing our evolving understanding of the ozone layer and for providing policy-relevant information.
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Langematz, Ulrike, Franziska Schmidt, Markus Kunze, Gregory E. Bodeker, and Peter Braesicke. "Antarctic ozone depletion between 1960 and 1980 in observations and chemistry–climate model simulations." Atmospheric Chemistry and Physics 16, no. 24 (December 20, 2016): 15619–27. http://dx.doi.org/10.5194/acp-16-15619-2016.
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Abstract. The year 1980 has often been used as a benchmark for the return of Antarctic ozone to conditions assumed to be unaffected by emissions of ozone-depleting substances (ODSs), implying that anthropogenic ozone depletion in Antarctica started around 1980. Here, the extent of anthropogenically driven Antarctic ozone depletion prior to 1980 is examined using output from transient chemistry–climate model (CCM) simulations from 1960 to 2000 with prescribed changes of ozone-depleting substance concentrations in conjunction with observations. A regression model is used to attribute CCM modelled and observed changes in Antarctic total column ozone to halogen-driven chemistry prior to 1980. Wintertime Antarctic ozone is strongly affected by dynamical processes that vary in amplitude from year to year and from model to model. However, when the dynamical and chemical impacts on ozone are separated, all models consistently show a long-term, halogen-induced negative trend in Antarctic ozone from 1960 to 1980. The anthropogenically driven ozone loss from 1960 to 1980 ranges between 26.4 ± 3.4 and 49.8 ± 6.2 % of the total anthropogenic ozone depletion from 1960 to 2000. An even stronger ozone decline of 56.4 ± 6.8 % was estimated from ozone observations. This analysis of the observations and simulations from 17 CCMs clarifies that while the return of Antarctic ozone to 1980 values remains a valid milestone, achieving that milestone is not indicative of full recovery of the Antarctic ozone layer from the effects of ODSs.
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Egorova, Tatiana, Jan Sedlacek, Timofei Sukhodolov, Arseniy Karagodin-Doyennel, Franziska Zilker, and Eugene Rozanov. "Montreal Protocol's impact on the ozone layer and climate." Atmospheric Chemistry and Physics 23, no. 9 (May 5, 2023): 5135–47. http://dx.doi.org/10.5194/acp-23-5135-2023.
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Abstract. It is now recognized and confirmed that the ozone layer shields the biosphere from dangerous solar UV radiation and is also important for the global atmosphere and climate. The observed massive ozone depletion forced the introduction of limitations on the production of halogen-containing ozone-depleting substances (hODSs) by the Montreal Protocol and its amendments and adjustments (MPA). Previous research has demonstrated the success of the Montreal Protocol and increased public awareness of its necessity. In this study, we evaluate the benefits of the Montreal Protocol on climate and ozone evolution using the Earth system model (ESM) SOCOLv4.0 (modeling tools for studies of SOlar Climate Ozone Links) which includes dynamic modules for the ocean, sea ice, interactive ozone, and stratospheric aerosol. Here, we analyze the results of the numerical experiments performed with and without limitations on the ozone-depleting substance (ODS) emissions. In the experiments, we have used CMIP6 (Coupled Model Intercomparison Project) SSP2-4.5 and SSP5-8.5 (Shared Socioeconomic Pathway) scenarios for future forcing behavior. We confirm previous results regarding catastrophic ozone layer depletion and substantial climate warming in the case without MPA limitations. We show that the climate effects of MPA consist of additional global-mean warming by up to 2.5 K in 2100 caused by the direct radiative effect of the hODSs, which is comparable to large climate warming obtained with the SSP5-8.5 scenario. For the first time, we reveal the dramatic effects of MPA on chemical species and cloud cover. The response of surface temperature, precipitation, and sea-ice fields was demonstrated for the first time with the model that has interactive tropospheric and stratospheric chemistry. We have found some differences in the climate response compared to the model with prescribed ozone, which should be further addressed. Our research updates and complements previous modeling studies on the quantifying of MPA benefits for the terrestrial atmosphere and climate.
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Drake, Frances. "Stratospheric ozone depletion - an overview of the scientific debate." Progress in Physical Geography: Earth and Environment 19, no. 1 (March 1995): 1–17. http://dx.doi.org/10.1177/030913339501900101.
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For almost half a century it was widely believed that the photochemistry of the stratosphere and hence ozone distribution were well understoood. As observations revealed a gap between observed and predicted values it was recognized that a number of substances acted as catalysts thereby increasing the destruction of ozone and that humanity could augment those catalysts and affect the ozone layer. Initial concern focused on nitrogen oxides from the exhausts of supersonic transport, but attention switched in the mid-1970s to chlorofluorocarbons (CFCs). Although the theory of anthropogenic ozone depletion by CFCs found widespread scientific support the perceived threat was minimized in particular by successive model predictions downgrading the amount of depletion. The appearance of the ozone hole over Antarctica in the mid-1980s reopened the debate as to whether such depletion was anthropogenic or natural in origin. It also highlighted the model's inadequate treatment of the processes occurring in the stratosphere and the importance of dynamics and radiative transfer in stratospheric ozone destruction. Scientific consensus again favours the anthropogenic depletion of the ozone layer. In conclusion it is considered that the degree of consensus outweighs the image of scientific uncertainty that is often portrayed in relation to the issue of stratospheric ozone depletion.
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Newman, P. A., L. D. Oman, A. R. Douglass, E. L. Fleming, S. M. Frith, M. M. Hurwitz, S. R. Kawa, et al. "What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?" Atmospheric Chemistry and Physics Discussions 8, no. 6 (December 10, 2008): 20565–606. http://dx.doi.org/10.5194/acpd-8-20565-2008.
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Abstract. Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, and modeling research. This science research led to the implementation of international agreements that largely stopped the production of ODSs. In this study we use a fully-coupled radiation-chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this "world avoided" simulation, 17% of the globally-average column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet radiation increases, more than doubling the erythemal radiation in the northern summer midlatitudes by 2060.
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Newman, P. A., L. D. Oman, A. R. Douglass, E. L. Fleming, S. M. Frith, M. M. Hurwitz, S. R. Kawa, et al. "What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?" Atmospheric Chemistry and Physics 9, no. 6 (March 23, 2009): 2113–28. http://dx.doi.org/10.5194/acp-9-2113-2009.
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Abstract. Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, and modeling studies. This science research led to the implementation of international agreements that largely stopped the production of ODSs. In this study we use a fully-coupled radiation-chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this "world avoided" simulation, 17% of the globally-averaged column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet radiation increases, more than doubling the erythemal radiation in the northern summer midlatitudes by 2060.
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Cao, L., H. Sihler, U. Platt, and E. Gutheil. "Numerical analysis of the chemical kinetic mechanisms of ozone depletion and halogen release in the polar troposphere." Atmospheric Chemistry and Physics 14, no. 7 (April 15, 2014): 3771–87. http://dx.doi.org/10.5194/acp-14-3771-2014.
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Abstract. The role of halogen species (e.g., Br, Cl) in the troposphere of polar regions has been investigated since the discovery of their importance for boundary layer ozone destruction in the polar spring about 25 years ago. Halogen species take part in an auto-catalytic chemical reaction cycle, which releases Br2 and BrCl from the sea salt aerosols, fresh sea ice or snowpack, leading to ozone depletion. In this study, three different chemical reaction schemes are investigated: a bromine-only reaction scheme, which then is subsequently extended to include nitrogen-containing compounds and chlorine species and corresponding chemical reactions. The importance of specific reactions and their rate constants is identified by a sensitivity analysis. The heterogeneous reaction rates are parameterized by considering the aerodynamic resistance, a reactive surface ratio, β, i.e., the ratio of reactive surface area to total ground surface area, and the boundary layer height, Lmix. It is found that for β = 1, a substantial ozone decrease occurs after five days and ozone depletion lasts for 40 h for Lmix = 200 m. For about β ≥ 20, the time required for major ozone depletion ([O3] < 4 ppb) to occur becomes independent of the height of the boundary layer, and for β = 100 it approaches two days, 28 h of which are attributable to the induction and 20 h to the depletion time. In polar regions, a small amount of NOx may exist, which stems from nitrate contained in the snow, and may have a strong impact on the ozone depletion. Therefore, the role of nitrogen-containing species on the ozone depletion rate is studied. The results show that the NOx concentrations are influenced by different chemical reactions over different time periods. During ozone depletion, the reaction cycle involving the BrONO2 hydrolysis is dominant. A critical value of 0.0004 of the uptake coefficient of the BrONO2 hydrolysis reaction at the aerosol and saline surfaces is identified, beyond which the existence of NOx species accelerates the ozone depletion event, whereas for lower values, deceleration occurs.
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Wu, Yutian, Lorenzo M. Polvani, and Richard Seager. "The Importance of the Montreal Protocol in Protecting Earth’s Hydroclimate." Journal of Climate 26, no. 12 (June 15, 2013): 4049–68. http://dx.doi.org/10.1175/jcli-d-12-00675.1.
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Abstract The 1987 Montreal Protocol regulating emissions of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODSs) was motivated primarily by the harm to human health and ecosystems arising from increased exposure to ultraviolet-B (UV-B) radiation associated with depletion of the ozone layer. It is now known that the Montreal Protocol has helped reduce radiative forcing of the climate system since CFCs are greenhouse gases (GHGs), and that ozone depletion (which is now on the verge of reversing) has been the dominant driver of atmospheric circulation changes in the Southern Hemisphere in the last half century. This paper demonstrates that the Montreal Protocol also significantly protects Earth’s hydroclimate. Using the Community Atmospheric Model, version 3 (CAM3), coupled to a simple mixed layer ocean, it is shown that in the “world avoided” (i.e., with CFC emissions not regulated), the subtropical dry zones would be substantially drier, and the middle- and high-latitude regions considerably wetter in the coming decade (2020–29) than in a world without ozone depletion. Surprisingly, these changes are very similar, in both pattern and magnitude, to those caused by projected increases in GHG concentrations over the same period. It is further shown that, by dynamical and thermodynamical mechanisms, both the stratospheric ozone depletion and increased CFCs contribute to these changes. The results herein imply that, as a consequence of the Montreal Protocol, changes in the hydrological cycle in the coming decade will be only half as strong as what they otherwise would be.
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Pandav, Prashant P., S. B. Lokhande, and Shivprakash B. Barve. "Ecofriendly Refrigerants." Applied Mechanics and Materials 612 (August 2014): 181–85. http://dx.doi.org/10.4028/www.scientific.net/amm.612.181.
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The depletion of ozone layer and green house effects are worldwide problem. Refrigerants are part and source of depletion of ozone layer. As we using these Ecofriendly refrigerants then harm to ozone reduces. These are best option for recently running refrigerants. Eco-friendly refrigerant like hydroflurocarbons and hydrocarbons are replacing chlorofluorocarbons application.CFC is the most important member of CFC refrigerants. This paper, gives alternate to refrigerants that are causes ill effect on environment. Their performance with respect to recently used refrigerant compared. By this comparison benefits of Ecofriendly refrigerants discussed.
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Evans, W. F. J. "A hole in the Arctic polar ozone layer during March 1986." Canadian Journal of Physics 67, no. 2-3 (February 1, 1989): 161–65. http://dx.doi.org/10.1139/p89-027.
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A craterlike structure or "hole" in the Arctic polar ozone layer during March 1986 has been observed in the total ozone images from the total ozone mapping spectrometer instrument on the NIMBUS 7 satellite. Observations from ozonesondes in the vicinity of this crater show a depleted region in the altitude profile from 10 to 16 km. This altitude region of depleted ozone is similar to the depleted layer observed from 12 to 18 km within the Antarctic ozone hole. A comparison has been made between the ozone altitude profile outside the crater at Resolute, N.W.T., Canada (75°N), and the ozone altitude profile inside the crater at Lindenberg, German Democratic Republic, (55°N). The difference in these profiles demonstrates that the crater is due to a process that has altered the altitude distribution of ozone in the 10–16 km region. This depletion could be attributed to either a vertical circulation or a chemical-depletion process.
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Cao, L., H. Sihler, U. Platt, and E. Gutheil. "Numerical analysis of the chemical kinetic mechanisms of ozone depletion and halogen release in the polar troposphere." Atmospheric Chemistry and Physics Discussions 13, no. 9 (September 13, 2013): 24171–222. http://dx.doi.org/10.5194/acpd-13-24171-2013.
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Abstract. In recent years, the role of halogen species (e.g. Br, Cl) in the troposphere of polar regions is investigated after the discovery of their importance for boundary layer ozone destruction in the polar spring. Halogen species take part in an auto-catalytic chemical cycle including key self reactions. In this study, several chemical reaction schemes are investigated, and the importance of specific reactions and their rate constants is identified by a sensitivity analysis. A category of heterogeneous reactions related to HOBr activate halogen ions from sea salt aerosols, fresh sea ice or snow pack, driving the "bromine explosion". In the Arctic, a small amount of NOx may exist, which comes from nitrate contained in the snow, and this NOx may have a strong impact on ozone depletion. The heterogeneous reaction rates are parameterized by considering the aerodynamic resistance, a reactive surface ratio, β, i.e. ratio of reactive surface area to total ground surface area, and the boundary layer height, Lmix. It is found that for β = 1, the ozone depletion process starts after five days and lasts for 40 h for Lmix = 200 m. Ozone depletion duration becomes independent of the height of the boundary layer for about β≥20, and it approaches a value of two days for β=100. The role of nitrogen and chlorine containing species on the ozone depletion rate is studied. The calculation of the time integrated bromine and chlorine atom concentrations suggests a value in the order of 103 for the [Br] / [Cl] ratio, which reveals that atomic chlorine radicals have minor direct influence on the ozone depletion. The NOx concentrations are influenced by different chemical cycles over different time periods. During ozone depletion, the reaction cycle involving the BrONO2 hydrolysis is dominant. A critical value of 0.002 of the uptake coefficient of the BrONO2 hydrolysis reaction at the aerosol and saline surfaces is identified, beyond which the existence of NOx species accelerate the ozone depletion event – for lower values, deceleration occurs.
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Anderson, Alun. "Depletion of ozone layer drives competitors to cooperate." Nature 331, no. 6153 (January 21, 1988): 201. http://dx.doi.org/10.1038/331201a0.
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Strong, C., J. D. Fuentes, R. E. Davis, and J. W. Bottenheim. "Thermodynamic attributes of Arctic boundary layer ozone depletion." Atmospheric Environment 36, no. 15-16 (May 2002): 2641–52. http://dx.doi.org/10.1016/s1352-2310(02)00114-0.
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Piot, M., and R. von Glasow. "The chemistry influencing ODEs in the Polar Boundary Layer in spring: a model study." Atmospheric Chemistry and Physics Discussions 8, no. 2 (April 16, 2008): 7391–453. http://dx.doi.org/10.5194/acpd-8-7391-2008.
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Abstract. Near-total depletions of ozone have been observed in the Arctic spring since the mid 1980s. The autocatalytic cycles involving reactive halogens are now recognized to be of main importance for Ozone Depletion Events (ODEs) in the Polar Boundary Layer (PBL). We present sensitivity studies using the model MISTRA in the box-model mode on the influence of chemical species on these ozone depletion processes. In order to test the sensitivity of the chemistry under polar conditions, we compared base runs undergoing fluxes of either Br2, BrCl, or Cl2 to induce ozone depletions, with similar runs including a modification of the chemical conditions. The role of HCHO, H2O2, DMS, Cl2, C2H4, C2H6, HONO, NO2, and RONO2 was investigated. Cases with elevated mixing ratios of HCHO, H2O2, DMS, Cl2, and HONO induced a shift in bromine speciation from Br/BrO to HOBr/HBr, while high mixing ratios of C2H6 induced a shift from HOBr/HBr to Br/BrO. Cases with elevated mixing ratios of HONO, NO2, and RONO2 induced a shift to BrNO2/BrONO2. The shifts from Br/BrO to HOBr/HBr accelerated the aerosol debromination, but also increased the total amount of deposited bromine at the surface (mainly via increased deposition of HOBr). These shifts to HOBr/HBr also hindered the BrO self-reaction. In these cases, the ozone depletion was slowed down, where increases in H2O2 and HONO had the greatest effect. The tests with increased mixing ratios of C2H4 highlighted the decrease in HOx which reduced the production of HOBr from bromine radicals. In addition, the direct reaction of C2H4 with bromine atoms led to less available reactive bromine. The aerosol debromination was therefore strongly reduced. Ozone levels were highly affected by the chemistry of C2H4. Cl2-induced ozone depletions were found unrealistic compared to field measurements due to the rapid production of CH3O2, HOx, and ROOH which rapidly convert reactive chlorine to HCl in a "chlorine counter-cycle". This counter-cycle efficiently reduces the concentration of reactive halogens in the boundary layer. Depending on the relative bromine and chlorine mixing ratios, the production of CH3O2, HOx, and ROOH from the counter-cycle can significantly affect the bromine chemistry. Therefore, the presence of both bromine and chlorine in the air may unexpectedly lead to a slow down in ozone destruction. For all NOy species studied (HONO, NO2, RONO2) the chemistry is characterized by an increased bromine deposition on snow reducing the amount of reactive bromine in the air. Ozone is less depleted under conditions of high mixing ratios of NOx. The production of HNO3 led to the acid displacement of HCl, and the release of chlorine out of salt aerosols (Cl2 or BrCl) increased.
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Zhang, Erjia. "The recovery of the Antarctic ozone layer and suggestions for addressing the global warming." Applied and Computational Engineering 58, no. 1 (April 30, 2024): 112–18. http://dx.doi.org/10.54254/2755-2721/58/20240703.
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The ozone layer is a critical shield for humanity, located in the Earths atmosphere with a high ozone concentration. Its primary role is to absorb and filter out the majority of harmful ultraviolet rays emitted by the sun, which pose a threat to all living beings. However, the ozone layer suffered from very severe depletion. To counteract this, the Montreal Convention was established in 1987, mandating a reduction in chlorofluorocarbon emissions by humans. Because of the environmental problem of ozone layer destruction for a long time, based on some existing research background at this stage, people find that the ozone layer is gradually recovering through observation of some data. In this essay, it explains the causal factors behind the depletion of the Antarctic ozone layer, as well as the various elements that contribute to its recovery and their respective levels of significance, through some research. Additionally, this essay explores how these models can be applied to address other environmental concerns. To achieve a more comprehensive understanding of this subject, this paper has conducted an intensive search through various academic references. In conclusion, through the use of balloon and satellite ozone data, a chemistry-climate model, and volcanic aerosol measurements, the healing of the Antarctic ozone layer is contributed by three factors: chemical reduction, kinetics, and temperature. Among these factors, chemical factors have the greatest contribution.
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Crang, Richard F. E., Audrey E. Vassilyev, and Yevgeney A. Miroslavov. "Soybean chloroplast responses to enhanced ultraviolet irradiation." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 348–49. http://dx.doi.org/10.1017/s0424820100147582.
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Environmental concerns over the degradation of the earth’s stratospheric ozone layer have been expressed for the past decade in recognition that with ozone depletion, enhanced ultraviolet irradiation will be received at the earth's surface. Such increase in ultraviolet irradiation can be hypothetically determined by making appropriate computer calculations based on proposed cloud cover, season, latitude, elevation, and percent of stratospheric ozone depletion. We have proposed a 40% reduction in the ozone layer corresponding to a daily increase of 19.1 kJ in the limits of ultraviolet-B (UV-B) spectral irradiation (280-320 nm). This is within the range of realistic possibilities based on current estimated ozone depletion rates for the next 40-50 years. We wish to determine the extent to which chloroplasts are ultrastructurally altered compared with those from plants raised under ambient conditions lacking an UV-B irradiation component.Uninoculated seeds of soybean (Glycine max), cv. “Forrest” were sown in standardized greenhouse soil in 4" clay pots, watered daily, and fertilized once per week.
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Al-Sharoot, Mustafa Ali. "Freon’s Destroy the Stratosphere." IOP Conference Series: Earth and Environmental Science 1223, no. 1 (August 1, 2023): 012001. http://dx.doi.org/10.1088/1755-1315/1223/1/012001.
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Abstract First of all, we have to know that the ozone layer exists in different levels of the Earth’s atmosphere. After follow-up, it was found that the equivalent of 80% of the ozone is found at altitudes between 16 and 35 kilometres above the earth’s surface. At this level it provides a good sunscreen shield, and we believe that is a good ozone. It is also present at ground level in low concentrations (tropospheric ozone). It is believed that the ozone at this stage is the polluting part and that the smog over the cities is the main part of it and it can be called (bad ozone). Through this thing, we must realize that the international community has not remained silent about air violations and took a number of measures to restore the ozone layer, most notably the Montreal Protocol in 1987. Here it was necessary for all countries of the world to develop solutions that work to gradually get rid of this time bomb by uniting on one decision, It is to stop the production or import of all materials that have a role in the depletion of the ozone because they have a direct impact on the depletion of the stratosphere. This paper seeks to serve two functions. First: it gives fundamental information about the Stratospheric ozone depletion process, with the goal of utilizing current worldwide knowledge on Measures to minimize the use of ozone-depleting compounds existing alternatives and current advances. As a result a supportive framework for Iraq to control its internal problem has been established. Second: an overview of the state of ozone-depleting compounds in Iraq including the industries that use them the difficulties in restricting their use, and the awareness and measures made to reduce their use in Iraq. We believe that this paper will give policymakers with the information they need to solve this issue, such as by giving alternatives and enumerating the roles of environmental protection agencies, user businesses, and the government itself in reducing the use of these compounds. We are convinced that our efforts will assist the general population who is concerned about the ozone layer’s degradation.
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Ibrahim, Ruaa M., Zainab M. Abbood, Osama T. Al-Taai, and Mohamad M. Ahmed. "The Influence of Ozone Depletion Potential Weighted Anthropogenic Emissions of Nitrous Oxide." Asian Journal of Water, Environment and Pollution 21, no. 2 (March 28, 2024): 65–73. http://dx.doi.org/10.3233/ajw240023.
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The effects of anthropogenic emissions of nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4), and halocarbons on stratospheric ozone (O3) over the twentieth and twenty-first centuries are divided using a chemical model of the stratosphere. As halocarbon levels revert to pre-industrial levels, N2O and CO2 will likely play the primary roles in the evolution of ozone in the future. It is unable to distinguish clearly between these gases’ effects on ozone due to nonlinear interactions between them. The work was conducted using the monthly and annual data of the gases in the stratospheric layer to determine the overlap between N2O and O3 for the Iraq station and for the period (2003-2016). The strength of the association between gases was determined using the Spearman rho test (rs). It was found that there is a very high positive relationship between the N2O and O3 in Nasriyah station, which is 0.807 which indicates a strong association. This is because meteorological conditions, climatic fluctuations, and atmospheric location all affect correlation. The ozone layer is destroyed by nitrous oxide at high concentrations through the stratosphere layer and the tropospheric layer, the concentration of ozone increases with an increase in the concentration of nitrogen dioxide.
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Chung, Jin Won, and Hee Chul An. "In-Depth Study for Environmental Impact Assessment of EPS(Electric Power Steering) using Life Cycle Assessment (LCA)." Korean Journal of Life Cycle Assessment 24, no. 1 (December 2023): 5–9. http://dx.doi.org/10.62765/kjlca.2023.24.1.5.
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This study was quantified using LCA about EPS limited system boundary from raw material extraction until it leaves the factory and assessed six environmental impact categories; Abiotic depletion; Acidification; Eutrophication; Global warming; Ozone layer depletion; and Photochemical oxidants creation. The contributions of raw material extraction to the six environmental impact categories were determined to be as follows:Abiotic depletion 85.2%, Acidification 93.8%, Eutrophication 89.7%, Global warming 86.3%, Ozone layer depletion 99.5%, and Photochemical oxidants creation 93.1%. Sensitivity analysis was performed for data and assumptions to confirm the results reliability of this study. The results of this study confirmed that raw material extraction stage and aluminum material part is the most important environmental impact factors in EPS.
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Siegmund, Peter, Henk Eskes, and Peter van Velthoven. "Antarctic Ozone Transport and Depletion in Austral Spring 2002." Journal of the Atmospheric Sciences 62, no. 3 (March 1, 2005): 838–47. http://dx.doi.org/10.1175/jas-3320.1.
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Abstract The ozone budget in the Antarctic region during the stratospheric warming in 2002 is studied, using ozone analyses from the Royal Netherlands Meteorological Institute (KNMI) ozone-transport and assimilation model called TM3DAM. The results show a strong poleward ozone mass flux during this event south of 45°S between about 20 and 40 hPa, which is about 5 times as large as the ozone flux in 2001 and 2000, and is dominated by eddy transport. Above 10 hPa, there exists a partially compensating equatorward ozone flux, which is dominated by the mean meridional circulation. During this event, not only the ozone column but also the ozone depletion rate in the Antarctic region, computed as a residual from the total ozone tendency and the ozone mass flux into this region, is large. The September–October integrated ozone depletion in 2002 is similar to that in 2000 and larger than that in 2001. Simulations for September 2002 with and without ozone assimilation and parameterized ozone chemistry indicate that the parameterized ozone chemistry alone is able to produce the evolution of the ozone layer in the Antarctic region in agreement with observations. A comparison of the ozone loss directly computed from the model’s chemistry parameterization with the residual ozone loss in a simulation with parameterized chemistry but without ozone assimilation shows that the numerical error in the residual ozone loss is small.
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Bhat, Nisar, Vijay Rawat, A. Malik, and Renu Singh. "Climate change and its impact on vegetation." Indian Journal of Forestry 32, no. 4 (December 1, 2009): 575–80. http://dx.doi.org/10.54207/bsmps1000-2009-361ht2.
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Climate change will affect on vegetation directly because of increased atmospheric CO2 concentration and greenhouse gases and indirectly through stratospheric ozone layer depletion. Increased CO2 level could increase photosynthesis and water use efficiency. However, high temperature and greenhouse gases will modify rainfall, evaporation runoff and soil moisture storage and will adversely affect growth and productivity. The increased amount of ultraviolet (UV) radiation due to depletion of stratospheric ozone layer will exert its deleterious effect on growth and productivity by destruction of chlorophyll and reducing photosynthetic rate.
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Simpson, W. R., R. von Glasow, K. Riedel, P. Anderson, P. Ariya, J. Bottenheim, J. Burrows, et al. "Halogens and their role in polar boundary-layer ozone depletion." Atmospheric Chemistry and Physics Discussions 7, no. 2 (March 29, 2007): 4285–403. http://dx.doi.org/10.5194/acpd-7-4285-2007.
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Abstract. During springtime in the polar regions, unique photochemistry converts inert halide salts ions (e.g. Br−) into reactive halogen species (e.g. Br atoms and BrO) that deplete ozone in the boundary layer to near zero levels. Since their discovery in the late 1980s, research on ozone depletion events (ODEs) has made great advances; however many key processes remain poorly understood. In this article we review the history, chemistry, dependence on environmental conditions, and impacts of ODEs. This research has shown the central role of bromine photochemistry, but how salts are transported from the ocean and are oxidized to become reactive halogen species in the air is still not fully understood. Halogens other than bromine (chlorine and iodine) are also activated through incompletely understood mechanisms that are probably coupled to bromine chemistry. The main consequence of halogen activation is chemical destruction of ozone, which removes the primary precursor of atmospheric oxidation, and generation of reactive halogen atoms/oxides that become the primary oxidizing species. The different reactivity of halogens as compared to OH and ozone has broad impacts on atmospheric chemistry, including near complete removal and deposition of mercury, alteration of oxidation fates for organic gases, and export of bromine into the free troposphere. Recent changes in the climate of the Arctic and state of the Arctic sea ice cover are likely to have strong effects on halogen activation and ODEs; however, more research is needed to make meaningful predictions of these changes.
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Simpson, W. R., R. von Glasow, K. Riedel, P. Anderson, P. Ariya, J. Bottenheim, J. Burrows, et al. "Halogens and their role in polar boundary-layer ozone depletion." Atmospheric Chemistry and Physics 7, no. 16 (August 22, 2007): 4375–418. http://dx.doi.org/10.5194/acp-7-4375-2007.
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Abstract. During springtime in the polar regions, unique photochemistry converts inert halide salt ions (e.g. Br−) into reactive halogen species (e.g. Br atoms and BrO) that deplete ozone in the boundary layer to near zero levels. Since their discovery in the late 1980s, research on ozone depletion events (ODEs) has made great advances; however many key processes remain poorly understood. In this article we review the history, chemistry, dependence on environmental conditions, and impacts of ODEs. This research has shown the central role of bromine photochemistry, but how salts are transported from the ocean and are oxidized to become reactive halogen species in the air is still not fully understood. Halogens other than bromine (chlorine and iodine) are also activated through incompletely understood mechanisms that are probably coupled to bromine chemistry. The main consequence of halogen activation is chemical destruction of ozone, which removes the primary precursor of atmospheric oxidation, and generation of reactive halogen atoms/oxides that become the primary oxidizing species. The different reactivity of halogens as compared to OH and ozone has broad impacts on atmospheric chemistry, including near complete removal and deposition of mercury, alteration of oxidation fates for organic gases, and export of bromine into the free troposphere. Recent changes in the climate of the Arctic and state of the Arctic sea ice cover are likely to have strong effects on halogen activation and ODEs; however, more research is needed to make meaningful predictions of these changes.
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Pekel, Feyzi Osman, and Esra Özay. "Turkish High School Students' Perceptions of Ozone Layer Depletion." Applied Environmental Education & Communication 4, no. 2 (April 2005): 115–23. http://dx.doi.org/10.1080/15330150590934598.
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Dameris, Martin. "Depletion of the Ozone Layer in the 21st Century." Angewandte Chemie International Edition 49, no. 3 (December 8, 2009): 489–91. http://dx.doi.org/10.1002/anie.200906334.
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Kazantzidou, Dimitra, and Konstantinos T. Kotsis. "Representation of the ozone layer in children’s trade books about ozone layer depletion: An analysis of written texts in Greece." Interdisciplinary Journal of Environmental and Science Education 19, no. 1 (January 18, 2023): e2302. http://dx.doi.org/10.29333/ijese/12847.
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Although children’s trade books are considered effective tools for introducing children to science content, studies have concluded that children form alternative ideas about science topics when the information presented in children’s books is inaccurate. The aim of the present study is to examine how stratospheric ozone is represented in children’s books about ozone layer depletion and whether these representations could foster alternative ideas about the topic. A total of nine books, published for preschool and primary school-aged children in Greece, were selected for analysis. Each of the nine books was analyzed using qualitative content analysis. The cognitive elements and information provided by the texts concerning the nature and role of ozone were organized into categories and compared with the scientific consensus view. The results revealed that all books identified in this study provided information about the nature of ozone while two books presented its role in the atmosphere. However, the topic was inadequately covered as misrepresentations about the position, distribution, and origin of ozone, its role in the atmosphere and the mechanism preventing UV radiation from reaching the Earth were recorded. Even though children’s books support science teaching and learning, the limitations appearing in the books require teachers to correct the texts or use additional scientifically accurate material to teach about the ozone layer and its depletion adequately and accurately. Collaboration between publishing companies, authors, and science consultants is recommended for improving the representation of science topics in children’s literature.
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Asira, Enim Enim. "Characterization of Chemical Processes Involved in Ozone Depletion." International Letters of Chemistry, Physics and Astronomy 21 (November 2013): 53–57. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.21.53.
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The earth’s carrying capacity to support human life has been overstretched by increasing need to meet food requirements, consumption of resources; amount of waste generation and choice of technologies. These activities release into the atmosphere, chemical constituents of varied concentrations. When these chemicals enter into the atmosphere, they are subjected to various transformations that yield products or intermediates that tend to alter atmospheric chemical balance. In recent years, the global problem of ozone depletion has underscored the danger of overstepping earth’s ability to absorb waste products. This study therefore, focuses on the various chemical reactions involved in ozone depletion and the effects of ozone layer depletion on plant, animals, materials and climate.
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Asira, Enim Enim. "Characterization of Chemical Processes Involved in Ozone Depletion." International Letters of Chemistry, Physics and Astronomy 21 (November 4, 2013): 53–57. http://dx.doi.org/10.56431/p-l8zq0u.
Full textAbstract:
The earth’s carrying capacity to support human life has been overstretched by increasing need to meet food requirements, consumption of resources; amount of waste generation and choice of technologies. These activities release into the atmosphere, chemical constituents of varied concentrations. When these chemicals enter into the atmosphere, they are subjected to various transformations that yield products or intermediates that tend to alter atmospheric chemical balance. In recent years, the global problem of ozone depletion has underscored the danger of overstepping earth’s ability to absorb waste products. This study therefore, focuses on the various chemical reactions involved in ozone depletion and the effects of ozone layer depletion on plant, animals, materials and climate.
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Parrondo, M. C., M. Gil, M. Yela, B. J. Johnson, and H. A. Ochoa. "Antarctic ozone variability inside the polar vortex estimated from balloon measurements." Atmospheric Chemistry and Physics 14, no. 1 (January 9, 2014): 217–29. http://dx.doi.org/10.5194/acp-14-217-2014.
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Abstract. Thirteen years of ozone soundings at the Antarctic Belgrano II station (78° S, 34.6° W) have been analysed to establish a climatology of stratospheric ozone and temperature over the area. The station is inside the polar vortex during the period of development of chemical ozone depletion. Weekly periodic profiles provide a suitable database for seasonal characterization of the evolution of stratospheric ozone, especially valuable during wintertime, when satellites and ground-based instruments based on solar radiation are not available. The work is focused on ozone loss rate variability (August–October) and its recovery (November–December) at different layers identified according to the severity of ozone loss. The time window selected for the calculations covers the phase of a quasi-linear ozone reduction, around day 220 (mid-August) to day 273 (end of September). Decrease of the total ozone column over Belgrano during spring is highly dependent on the meteorological conditions. Largest depletions (up to 59%) are reached in coldest years, while warm winters exhibit significantly lower ozone loss (20%). It has been found that about 11% of the total O3 loss, in the layer where maximum depletion occurs, takes place before sunlight has arrived, as a result of transport to Belgrano of air from a somewhat lower latitude, near the edge of the polar vortex, providing evidence of mixing inside the vortex. Spatial homogeneity of the vortex has been examined by comparing Belgrano results with those previously obtained for South Pole station (SPS) for the same altitude range and for 9 yr of overlapping data. Results show more than 25% higher ozone loss rate at SPS than at Belgrano. The behaviour can be explained taking into account (i) the transport to both stations of air from a somewhat lower latitude, near the edge of the polar vortex, where sunlight reappears sooner, resulting in earlier depletion of ozone, and (ii) the accumulated hours of sunlight, which become much greater at the South Pole after the spring equinox. According to the variability of the ozone hole recovery, a clear connection between the timing of the breakup of the vortex and the monthly ozone content was found. Minimum ozone concentration of 57 DU in the 12–24 km layer remained in November, when the vortex is more persistent, while in years when the final stratospheric warming took place "very early", mean integrated ozone rose by up to 160–180 DU.
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Thompson, C. R., P. B. Shepson, J. Liao, L. G. Huey, E. C. Apel, C. A. Cantrell, F. Flocke, et al. "Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska." Atmospheric Chemistry and Physics Discussions 14, no. 21 (November 19, 2014): 28685–755. http://dx.doi.org/10.5194/acpd-14-28685-2014.
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Abstract. The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indications of active iodine chemistry through observed enhancements in filterable iodide, probable detection of tropospheric IO, and recently, detection of atmospheric I2. Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. To investigate this, we developed a zero-dimensional photochemical model, constrained with measurements from the 2009 OASIS field campaign in Barrow, Alaska. We simulated a 7 day period during late March that included a full ozone depletion event lasting 3 days and subsequent ozone recovery to study the interactions of halogen radicals under these different conditions. In addition, the effects of iodine added to our base model were investigated. While bromine atoms were primarily responsible for ODEs, chlorine and iodine were found to enhance the depletion rates and iodine was found to be more efficient per atom at depleting ozone than Br. The interaction between chlorine and bromine is complex, as the presence of chlorine can increase the recycling and production of Br atoms, while also increasing reactive bromine sinks under certain conditions. Chlorine chemistry was also found to have significant impacts on both HO2 and RO2. The results of this work highlight the need for future studies on the production mechanisms of Br2 and Cl2, as well as on the potential impact of iodine in the High Arctic.
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Thompson, C. R., P. B. Shepson, J. Liao, L. G. Huey, E. C. Apel, C. A. Cantrell, F. Flocke, et al. "Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska." Atmospheric Chemistry and Physics 15, no. 16 (August 28, 2015): 9651–79. http://dx.doi.org/10.5194/acp-15-9651-2015.
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Abstract. The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indications of active iodine chemistry through observed enhancements in filterable iodide, probable detection of tropospheric IO, and recently, observation of snowpack photochemical production of I2. Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. To investigate this, we developed a zero-dimensional photochemical model, constrained with measurements from the 2009 OASIS field campaign in Barrow, Alaska. We simulated a 7-day period during late March that included a full ozone depletion event lasting 3 days and subsequent ozone recovery to study the interactions of halogen radicals under these different conditions. In addition, the effects of iodine added to our Base Model were investigated. While bromine atoms were primarily responsible for ODEs, chlorine and iodine were found to enhance the depletion rates and iodine was found to be more efficient per atom at depleting ozone than Br. The interaction between chlorine and bromine is complex, as the presence of chlorine can increase the recycling and production of Br atoms, while also increasing reactive bromine sinks under certain conditions. Chlorine chemistry was also found to have significant impacts on both HO2 and RO2, with organic compounds serving as the primary reaction partner for Cl atoms. The results of this work highlight the need for future studies on the production mechanisms of Br2 and Cl2, as well as on the potential impact of iodine in the High Arctic.
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Andersen, Stephen. "Global Impact of the CFC Phaseout." Journal of the IEST 34, no. 3 (May 1, 1991): 17–22. http://dx.doi.org/10.17764/jiet.2.34.3.r354m3502qt24423.
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The amendments to the Montreal Protocol and the 1990 Clean Air Act call for the accelerated reduction of fully halogenated CFCs and halons. Recent scientific data indicate that these chemicals are more damaging to the earth's ozone layer than previously thought. This ozone depletion has serious consequences for the environment and human health. These chemical compounds are scheduled for phaseout under the Montreal Protocol and Clean Air Act. Because CFC-13 and methyl chloroform are used extensively in the electronics industry worldwide, the industry and the U.S. EPA have formed a partnership to develop technically feasible, cost-effective, and environmentally sound alternatives for ozone-depleting substances.
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Chen, Xuemeng, Lauriane L. J. Quéléver, Pak L. Fung, Jutta Kesti, Matti P. Rissanen, Jaana Bäck, Petri Keronen, et al. "Observations of ozone depletion events in a Finnish boreal forest." Atmospheric Chemistry and Physics 18, no. 1 (January 3, 2018): 49–63. http://dx.doi.org/10.5194/acp-18-49-2018.
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Abstract. We investigated the concentrations and vertical profiles of ozone over a 20-year period (1996–2016) at the SMEAR II station in southern Finland. Our results showed that the typical daily median ozone concentrations were in the range of 20–50 ppb with clear diurnal and annual patterns. In general, the profile of ozone concentrations illustrated an increase as a function of heights. The main aim of our study was to address the frequency and strength of ozone depletion events at this boreal forest site. We observed more than a thousand of 10 min periods at 4.2 m, with ozone concentrations below 10 ppb, and a few tens of cases with ozone concentrations below 2 ppb. Among these observations, a number of ozone depletion events that lasted for more than 3 h were identified, and they occurred mainly in autumn and winter months. The low ozone concentrations were likely related to the formation of a low mixing layer under the conditions of low temperatures, low wind speeds, high relative humidities and limited intensity of solar radiation.
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Jones, A. E., P. S. Anderson, M. Begoin, N. Brough, M. A. Hutterli, G. J. Marshall, A. Richter, H. K. Roscoe, and E. W. Wolff. "BrO, blizzards, and drivers of polar tropospheric ozone depletion events." Atmospheric Chemistry and Physics Discussions 9, no. 2 (April 3, 2009): 8903–41. http://dx.doi.org/10.5194/acpd-9-8903-2009.
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Abstract. The source of bromine that drives polar boundary layer ozone depletion events (ODEs) is still open to some debate. While ODEs are generally noted to form under conditions of a shallow stable boundary layer, observations of depleted air under high wind conditions are taken as being transport-related. Here we report observations from Antarctica in which an unusually large cloud of BrO formed over the Weddell Sea. The enhanced BrO was observed over Halley station in coastal Antarctica, providing an opportunity to probe the conditions within an active "bromine explosion" event. On this occasion, enhanced BrO and depleted boundary layer ozone coincided with high wind speeds and saline blowing snow. We derive a simple model to consider the environmental conditions that favour ODEs and find two maxima, one at low wind/stable boundary layer and one at high wind speeds with blowing snow. Modelling calculations aiming to reproduce the wider regional or global impacts of ODEs, either via radiative effects or as a halogen source, will also need to account for high wind speed mechanisms.
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Jones, A. E., P. S. Anderson, M. Begoin, N. Brough, M. A. Hutterli, G. J. Marshall, A. Richter, H. K. Roscoe, and E. W. Wolff. "BrO, blizzards, and drivers of polar tropospheric ozone depletion events." Atmospheric Chemistry and Physics 9, no. 14 (July 17, 2009): 4639–52. http://dx.doi.org/10.5194/acp-9-4639-2009.
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Abstract. The source of bromine that drives polar boundary layer ozone depletion events (ODEs) is still open to some debate. While ODEs are generally noted to form under conditions of a shallow stable boundary layer, observations of depleted air under high wind conditions are taken as being transport-related. Here we report observations from Antarctica in which an unusually large cloud of BrO formed over the Weddell Sea. The enhanced BrO was observed over Halley station in coastal Antarctica, providing an opportunity to probe the conditions within an active "bromine explosion" event. On this occasion, enhanced BrO and depleted boundary layer ozone coincided with high wind speeds and saline blowing snow. We derive a simple model to consider the environmental conditions that favour ODEs and find two maxima, one at low wind/stable boundary layer and one at high wind speeds with blowing snow. Modelling calculations aiming to reproduce the wider regional or global impacts of ODEs, either via radiative effects or as a halogen source, will also need to account for high wind speed mechanisms.
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Seabrook, J. A., J. A. Whiteway, L. H. Gray, R. Staebler, and A. Herber. "Airborne lidar measurements of surface ozone depletion over Arctic sea ice." Atmospheric Chemistry and Physics 13, no. 12 (June 22, 2013): 6023–29. http://dx.doi.org/10.5194/acp-13-6023-2013.
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Abstract. A differential absorption lidar (DIAL) for measurement of atmospheric ozone concentration was operated aboard the Polar 5 research aircraft in order to study the depletion of ozone over Arctic sea ice. The lidar measurements during a flight over the sea ice north of Barrow, Alaska, on 3 April 2011 found a surface boundary layer depletion of ozone over a range of 300 km. The photochemical destruction of surface level ozone was strongest at the most northern point of the flight, and steadily decreased towards land. All the observed ozone-depleted air throughout the flight occurred within 300 m of the sea ice surface. A back-trajectory analysis of the air measured throughout the flight indicated that the ozone-depleted air originated from over the ice. Air at the surface that was not depleted in ozone had originated from over land. An investigation into the altitude history of the ozone-depleted air suggests a strong inverse correlation between measured ozone concentration and the amount of time the air directly interacted with the sea ice.
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Afsar Alam, Mohammad. "Depleting State of Stratospheric Ozone: A Challenging Conservation for Global Community with special Reference to Eritrea." Journal for Geography 11, no. 1 (June 30, 2016): 7–26. http://dx.doi.org/10.18690/rg.11.1.3949.
Full textAbstract:
Though the basic needs of the humans are prioritized first, health and quality of environment are also equally important. Environmental issues are based on many and different things. One of these is the depleting state of Stratospheric Ozone in the atmosphere. The ozone layer is vital to life on earth because it acts as a filter for UV radiation, which can have severe impacts on human health and the earth’s environment. As estimated, every one per cent decrease in the ozone layer results in the increase of ultraviolet light intensity at the earth's surface by two per cent. Known effects of ultraviolet exposure include greater incidence of skin cancer and eye cataracts among humans and diminished crop yields for foods such as peas, beans, and squash and soya beans. Phytoplankton, the tiny one celled Ocean plants that are staple food for squid, fish, seals, and whales also are vulnerable to Ultra violet radiations. Depletion of ozone layer is one of the main issues of the world today. Concerning to these issue two important meetings had been hold i.e. known by the Montreal Protocol and Vienna Convention. Most of the world countries are part of this Montreal Protocol and Vienna Convention. Eritrea is also part of Montreal Protocol and Vienna Convention. In the present paper basically an attempt has been made to show the world’s concern in general and the Eritrea’s in particular about the conservation measures taken on mitigation of Ozone layer. This research paper also emphasizes on the global problem of Ozone Depleting Substances (ODSs) releasing from different industries and specific sources. Besides, the study further includes the existence of naturally created Ozone hole on the Polar Regions.
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Dreyfus, Gabrielle B., Stephen A. Montzka, Stephen O. Andersen, and Richard Ferris. "Technical note: A method for calculating offsets to ozone depletion and climate impacts of ozone-depleting substances." Atmospheric Chemistry and Physics 24, no. 3 (February 15, 2024): 2023–32. http://dx.doi.org/10.5194/acp-24-2023-2024.
Full textAbstract:
Abstract. By phasing out production and consumption of most ozone-depleting substances (ODSs), the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) has avoided consequences of increased ultraviolet (UV) radiation and will restore stratospheric ozone to pre-1980 conditions by mid-century, assuming compliance with the phaseout. However, several studies have documented an unexpected increase in emissions and suggested unreported production of trichlorofluoromethane (CFC-11) and potentially other ODSs after 2012 despite production phaseouts under the Montreal Protocol. Furthermore, because most ODSs are powerful greenhouse gases (GHGs), there are significant climate protection benefits in collecting and destroying the substantial quantities of historically allowed production of chemicals under the Montreal Protocol that are contained in existing equipment and products and referred to as ODS “banks”. This technical note presents a framework for considering offsets to ozone depletion, climate forcing, and other environmental impacts arising from occurrences of unexpected emissions and unreported production of Montreal Protocol controlled substances, as recently experienced and likely to be experienced again. We also show how this methodology could be applied to the destruction of banks of controlled ODSs and GHGs or to halon or other production allowed under a Montreal Protocol Essential Use Exemption or Critical Use Exemption. Further, we roughly estimate the magnitude of offset each type of action could provide for ozone depletion, climate, and other environmental impacts that Montreal Protocol Parties agree warrant remedial action.