Environmental concerns ozone layer

Evidence that many of these compounds can have adverse effects on the immune, endocrine and nervous systems and that some are carcinogenic has grown during the last decade. The role of chlorofluorocarbons (CFCs) and of methyl bromide in the ozone layer depletion is well established (ref. 3).It is therefore not surprising that many halogenated derivatives are cast as environmental and health villains by various concerned groups who call for total phase out of chlorine and chlorinated hydrocarbons. 

Many of the changes in chlorine consumption in the past ten years have arisen out of the environmental concern about the use of chlorine in some processes such as pulp and paper as well as the concern of the loss of the ozone layer with the use of CFCs. 

Environmental concerns are very important. Some gronps promote the pnrchase and nse of green products. Other groups act as watchdogs, calling public attention to mannfactnrers and corporations they perceive to be lagging in environmental responsibility. It is not easy on anyone nsing hazardous solvents, especially if they are released into the environment and can be linked to holes in the ozone layer or to ecosystem disturbances. 

The synthesis of fluoropolymers in C02 is of particular interest since these polymers have historically been prepared in chlorofluorocarbons (CFCs) and other fluorinated solvents, as well as in water. Due to the association of CFCs with ozone-layer depletion, these solvents have been banned and replacement solvents must be found. Alternative fluorinated solvents are expensive and also have environmental concerns. 

In this volume of Issues we address the sources, environmental cycles, uptake, consequences and control of many of the more important chlorinated organic micropollutants. Under this heading we have included a range of semi-volatile persistent compounds, notably polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) as well as a number of chlorinated pesticides. We have not sought to include volatile species such as CFCs which cause environmental problems of an entirely different nature. The compounds included in this volume cause no threat to the stratospheric ozone layer, but have given widespread cause for concern in relation to their environmental persistence and high toxicity, and their potential for adverse effects on humans and wildlife. 

It is anticipated that further environmental research will lead to a satisfactory resolution of the seemingly conflicting statements in the literature concerning the effect of phosgene on the ozone layer. 

As a final point we need to focus attention on a critically important risk issue that has been entirely neglected in this book, and that is only beginning to draw the attention it deserves. Our concern in this book has been focused on the effects on human health of exposures to environmental chemicals. We have not discussed how these chemicals may damage non-human life forms and even the inanimate environment (e.g., the ozone layer). This is an immense topic about which information is limited, but which could, in the long term, be more important in several respects than the topic of this book. An associate of mine has remarked that, somehow, the E has been taken out of EPA, suggesting that the agency has devoted much more attention to human health protection than to environmental protection. The lack... 

In the early to mid 1970s, hairspray sales declined even further because of environmental pressures to restrict the use of fluorocarbons in aerosol products. The largest drop in hairspray sales occurred in 1975, after Roland and Molina theorized how fluorocarbons deplete the ozone layer in the stratosphere. For additional details on the rise and the decline in hairspray sales, see the article by Root [53]. As indicated in the introductory section to this chapter, a great deal of current research is concerned with lowering VOCs in hair care products, and in particular in hairsprays, and the California (CARD) regulations outlined in the introduction are the driving force behind these efforts. 

Substances which give a concern for the structure or the function of the stratospheric ozone layer have to be labeled with R 59 and are also classified as environmentally toxic. 

Paul Crutzen, Mario Molina, and Sherwood Rowland shared the 1995 Nobel Prize in Chemistry for their work in atmospheric chemistry, particularly concerning the formation and decomposition of ozone. Born in Amsterdam, Mexico City and Delaware, Ohio, respectively, in 1974 these three scientists alerted the world to an impending environmental disaster, possible destruction of the protective ozone layer by manmade chemicals. And yet nothing in their early backgrounds would have predicted this. 

When we come to the second rung of petrochemical products, other environmental factors are more likely to have a greater impact on their continued use, such as concerns over emissions into the atmosphere of solvents (in general) and chlorine- and fluorine-containing fluids (affecting the ozone layer). The need to reduce pollutant emissions and land or water contamination by chemical processes is a separate matter, but could again affect the future selection of both products and process routes. 

Reduction in the volatile organic content (VOC) of coatings, contributed by the solvents present, is now required because solvents, principally hydrocarbons, contribute through a reaction chain to an increase in ground level pollution (photochemical ozone). The hole in the ozone layer in the stratosphere concerns chlorofluorocarbons (CFC) and is a very different issue. Also of concern to formulators is the removal of lead, chromium and cadmium, which are long term environmental pollutants in paint residues. 

Use of mercury and diaphragm cells is not the only environmental concern facing the industry demand for CI2 has fallen in the pulp and paper industry and in the production of chlorofluorocarbons, the latter being phased out as a result of the Montreal Protocol for the Protection of the Ozone Layer. Nevertheless, overall demand for CI2 remains high, much being used in the production of chloroethene... 

Concerning the environmental impact, toxicity, air pollution, water pollution and soil pollution are to evaluate, but also effects on the environment like Greenhouse effect, destruction of the ozon layer, disturbances by odour or noise and residues from processes are to take into account. These effects are very complex and evaluation or weighting is rather difficult. Some aspects of the environmental impact are discussed below. 

Chemicals such as CFCs and nitrogen oxides that damage the ozone layer are known as ozone-depleting chemicals (ODCs). Concern about the use of chlorofluorocarbons in particular led to the signing of the Montreal Protocol and the subsequent search for alternatives, as discussed earlier. The concerted international effort to resolve this situation remains, despite setbacks and complexities, the most successful environmental intervention achieved to date. 

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