Protecting Visibility in National Parks and Wilderness Areas (1993) / Chapter Skim
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6 Emission Controls and Visibility
6 Emission Controls and Visibility
Pages 209-238
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From page 209... ...
Any effective strategy to accomplish the congressionally established goal of remedying and preventing anthropogenic visibility impairment in Class ~ areas (Clean Air Act, §169A) requires limiting the emissions of pollutants that reduce visibility.
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From page 210... ...
also must be considered. In this chapter the committee provides an example, using a speciated rollback model, to apportion anthropogenic light extinction among source types in the eastern, southwestern, and northwestern United States.
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From page 211... ...
The excluded area contains important Class ~ areas such as Yellowstone National Park. APPORTIONMENT OF REGIONAL HAZE USING A SPECIATED ROLLBACK MODEL The committee used a speciated rollback model to apportion anthropogenic light extinction among source types in three large regions of the United States- the East (states east of the Mississippi River)
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From page 212... ...
The extended rollback models developed here pertain to anthropogenic light extinction, not just aerosol concentrations. The apportionment is achieved in two steps: First, visibility impairment is allocated among aerosol types by means of light extinction budget calculations (see Chapter 4)
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From page 213... ...
Tic ~ or '1: D %, .suspended dust (5'0: ~ . natural)
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From page 214... ...
Tables 6-3 through 6-5 apportion light extinction using the speciated rollback model. In keeping with the overall level of the analysis, the following simplistic precursor relationships are assumed: · Sulfate concentration is proportional to emissions of sulfur oxides (s ox)
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From page 215... ...
Appendix D describes control methods for major sources of visibility impairment in the regions modeled: electric utilities, industrial coal combustion, the petroleum and chemical industries and industrial of! combustion, nonferrous smelters, diesel-fueled and gasoline-fueled motor vehicles, fugitive dust, feedIots and livestock waste management, residential Woof burning, forest management burning, and organic solvent evaporation.
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From page 229... ...
would yield a 39% reduction in eastern anthropogenic light extinction (Table 6-~. The 1990 Clean Air Act amendments will require a reduction of approximately 50% in electric utility SO2 emissions nationwide by the year 2000 (most of the reduction is to take place in the East)
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230 PROTECTING VISIBILITY IN NATIONAL PARKS ~b~ ~ ~ ` Dimly mailable P ge :~ f ~ ..
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From page 234... ...
In the Southwest and Northwest, anthropogenic light extinction would be reduced by about 40%. Accounting for the larger relative contributions from natural sources in those less polluted regions, the reductions in total average light extinction are estimated to be only 15% in the Southwest and 26% in the Northwest.
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From page 235... ...
· Improving visibility substantially in the Southwest and Northwest will require the control of many source categories especially electric utilities, diesel-fueled and gasoline-fueled motor vehicles, petroleum and chemical industrial sources, forest management burning, and fugitive dust. · The visibility improvements in all regions would fall far short of the national goal of no anthropogenic impairment from regional haze.
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From page 236... ...
For example, controls aimed at reducing acid rain or lowering ambient concentrations of ozone and PM~o could improve visibility in Class ~ areas; conversely, controls aimed at improving visibility could alleviate other air-quality problems. Policy makers should weigh these linkages in the design and assessment of possible control strategies.
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From page 237... ...
In the Southwest and Northwest, no single source category is dominant; the major sources include gasoline- and diesel-fueled motor vehicles, electric utilities, industrial petroleum and chemical sources, and (in the Northwest) forest management burning.
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