Controlling Acid Rain

Acid rain and its effects were discussed in Chapter 7, Section 7.6. One of the two major contributors to acid rain are sulfur dioxide, which produces sulfurous acid, H2SO3, but, more importantly, sulfuric acid, H2SO4, and the acidic salt, NH4HSO4. The other major contributor is NOx, which is oxidized to HNO3 and may also contribute the acidic salt NH4NO3 to the atmosphere. There is some contribution to acid rain by HCl, primarily released in the burning of organochlorine materials, especially polyvinylchloride plastic. 

Acid rain is best controlled by limiting emissions to the atmosphere of sulfur dioxide and nitrogen oxides, discussed in Sections 8.6 and 8.7. Combustion of coal containing sulfur is a major source of atmospheric sulfur dioxide, the release of which can be limited by stack gas controls, fluidized bed combustion in a sulfur-sequestering medium, and removal of sulfur from coal before combustion 

Potential sources of atmospheric HCl can be limited by scrubbing stack gas from facilities where organochlorine compounds, especially polyvinylchloride plastic, are incinerated. To the extent possible, it is best to avoid incineration of such materials. 

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To control acid rain requires international cooperation and much effort has gone into crafting agreements between countries... 

A Strategy for Controlling Acid Rain Precursor Emissions... 

Congress had shifted in focus from whether or not acid rain was a problem to how to control acid rain and how to apportion the costs of doing so. And, sensitive to the direction of that debate, the once highly effective opposition alliance of electric utilities, coal companies, and coal miners began to splinter. ... 

Roberts, Hon. John, Minister of the Environment, Canada. (1980). The urgency of controlling acid rain. Speech to the Air Pollution Control Association, Mon-... 

The Urgency of Controlling Acid Rain, speech by the Hon. John Roberts, Minister of the Environment Canada, to the Air Pollution Control Association, Montreal, June 12, 1980, Statements and Speeches, No. 80/8, Department of External Affairs, Ottawa. 

Title IV Acid Deposition Control Acid rain occurs when sulfur dioxide and nitrogen oxide emissions are transformed in the atmosphere and return to the earth in rain, fog or snow. Approximately 20 million tons of SOj are emitted annually in the United States, mostly from the burning of fossil fuels by electric utilities. Acid... 

There are three major ways to reduce SO2 emissions from coal combustion 1) bum low-sulfur coal (less than 1% sulfur by weight) rather than high-sulfur coal (greater than 3% sulfur) 2) remove the sulfur from coal before it is burned ("coal cleaning ) and 3) use pollution-control devices to remove the sulfur during or after coal combustion. In a large-scale program to control acid rain, say one that required a 50% reduction in SO2 emissions, all three of these methods would come into play. 

Selection of pollution control methods is generally based on the need to control ambient air quaUty in order to achieve compliance with standards for critetia pollutants, or, in the case of nonregulated contaminants, to protect human health and vegetation. There are three elements to a pollution problem a source, a receptor affected by the pollutants, and the transport of pollutants from source to receptor. Modification or elimination of any one of these elements can change the nature of a pollution problem. For instance, tall stacks which disperse effluent modify the transport of pollutants and can thus reduce nearby SO2 deposition from sulfur-containing fossil fuel combustion. Although better dispersion aloft can solve a local problem, if done from numerous sources it can unfortunately cause a regional one, such as the acid rain now evident in the northeastern United States and Canada (see Atmospheric models). References 3—15 discuss atmospheric dilution as a control measure. The better approach, however, is to control emissions at the source. 

California land-use regulations and growth control Latin American environmental initiatives environmental issues, acid rain, recycling, greenhouse effect... 

The usage pattern in Europe and Japan is more dependent upon the automotive industry. However, with the recent concern about acid rain, the European and U.S. markets should show increased interest in fluorocarbon elastomers for pollution control appHcations. On the other hand, the Japanese market has a sizable outlet in electrical and general machinery manufacturing (eg, copiers). Petroleum appHcations are of Htfle interest outside the United States. 

Deals with issues that affect the quality of our air and protection from exposure to harmful radiation. OAR de >el-ops national programs, technical policies, and regulations for controlling air pollution and radiation exposure. Areas of concern to OAR include indoor and outdoor air quality, stationaiy and mobile sources of air pollution, radon, acid rain, stratospheric ozone depletion, radiation protection, and pollution prevention. 

Public concerns about air quality led to the passage of the Clean Air Act in 1970 to amendments to that act in 1977 and 1990. The 1990 amendments contained seven separate titles covering different regula-toiy programs and include requirements to install more advanced pollution control equipment and make other changes in industrial operations to reduce emissions of air pollutants. The 1990 amendments address sulfur dioxide emissions and acid rain deposition, nitrous oxide emissions, ground-level ozone, carbon monoxide emissions, particulate emissions, tail pipe emissions, evaporative emissions, reformulated gasoline, clean-fueled vehicles and fleets, hazardous air pollutants, solid waste incineration, and accidental chemical releases. 

Acid precipitation, or acid rain, can causes significant impacts on freshwater, coastal, and forested ecosystems (e.g.. Likens et ai, 1996). Both NOi", from NO emissions, and SO from SO2 emissions contribute significantly to acid rain. The relative ratio of SO /NOf in precipitation will be substantially determined by the regional emissions of SO2/NO3. In developed countries, uncontrolled combustion of coal and high-sulfur fuel oil led to significant emissions of SO2, relative to NO Due to strict control of smokestack SO2 emissions in some regions and increasing NO emissions from automobiles, the relative contribution of NOi is expected to increase (Sirois, 1993 Mayewski et ai, 1990). 

The demand for environment-friendly fuels requires the removal of organosulfur compounds present in crade-oil fractions. SO2 or SO3 contribute to the formation of acid rain and have an effect on pollution control devices [9]. Very stringent environmental regulations will limit the sulfur levels in diesel fuels in EU to less than 10 ppm by the end of 2010 [10]. The conventional sulfur-compound... 

What effect does acid rain have on the rate of corrosion of metals used in buildings, automobiles, and statues How can concentration of the acid in the rain, and thus the rate of corrosion, be controlled ... 

Hydrogen chloride and chlorine gases form when chlorinated organic compounds in hazardous wastes are burned. If uncontrolled, this chlorine can become a human health risk and is a large component in the formation of acid rain. U.S. EPA has developed different requirements to control the emissions of chlorine from the different classes of combustion units. 

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