![]() National research council environment and resources commission on geosciences. washington, d.c.: national academy press. haze in the grand canyon: an evaluation of the winter haze intensive tracer experiment. ![]() National research council board on environmental studies and toxicology. buyways: automobility, billboards and the american cultural landscape. Attempts to curb graffiti by banning the sale of spray paint to minors have had little effect. Names and messages, are a form of urban visual blight. One solution has been to disguise cell towers as trees or cacti. The latest fight against visual pollution centers on cell towers, needed to provide cellular telephone service. Sensitivity to visual pollution has led utility companies to bury power and telephone lines in some communities. This groundbreaking law prompted a number of states, including Alaska, Hawaii, Maine and Vermont, to ban billboards totally there were loopholes, however. "Ugliness is so grim," the first lady proclaimed, and she fought for and won passage of the Highway Beautification Act of 1965. But to the traveler whose view of the rolling hills or the rustic village is obstructed, it is visual pollution.īillboards proliferated in the 1940s and 1950s, spurred by the growth of automobile traffic and construction of interstate highway system, but in 1965 Lady Bird Johnson, wife of President Lyndon Johnson, attacked their growing presence on our nation's roadways. To the businessman, a well-placed billboard may be a thing of beauty. Visual blight -billboards, power lines, cell towers, even ugly buildings -is literally in the eye of the beholder. Some of the fires spread to peat deposits beneath the forest, and these may continue to burn for years. Most fires were set deliberately, and often illegally, to clear land for planting and development and to cover up illegal logging. Fires in Sumatra and Borneo affected not only Indonesia, but also Malaysia, Singapore, and Thailand. In Southeast Asia, haze caused by massive forest fires cost billions of dollars in health care and lost tourist revenue in the last decade. States to establish goals and strategies and to work together in regional groups to improve visibility in 156 national parks and wilderness areas. Environmental Protection Agency (EPA) has issued regional haze regulations that call on Controls designed to reduce the pollution from vehicular and smokestack emissions will also reduce visual pollution. The pollutants that cause haze are also a health concern because they often result in respiratory problems among humans and other species. Wood smoke is a contributor in the west, and forest fire smoke and windblown dust are natural sources of haze. The pollution that causes haze can travel thousands of miles, and improving regional visibility requires interstate cooperation. The haze problem is greatest on the east coast of the United States because of the higher levels of pollution and humidity in that region. Utility boilers and vehicular emissions are both major sources of haze-causing pollution. The result was a landmark settlement in which Navajo's owners agreed to a 90-percent cutback in sulfur dioxide emissions by 1999. When monitors determined the presence of deuterium in canyon air, researchers were able to demonstrate that the plant was responsible for much of the canyon haze. Deuterium is not normally present in the air. In 1985 researchers at Colorado State University injected methane-containing deuterium into the power plant's smoke emissions. An enormous coal-fired electric plant, the Navajo Power Generating Station, about 80 miles north of the Grand Canyon, was thought to be the source of the pollution causing canyon haze. At its worst, haze at Grand Canyon National Park was so severe that people could not see across the 10-mile wide canyon. On a hazy day, that can be reduced to 30 miles. At Acadia National Park in Maine, visual range on a clear day can be 199 miles. Haze is most dramatically seen as a brownish-grey cloud hovering over cities, but it also obscures many beautiful vistas in U.S. The larger the particles, the more light they scatter. Haze increases with summer humidity because sulfate and other particles absorb moisture and increase in size. Nitrogen dioxide and other pollution gases also contribute to haze. It is caused when light is absorbed or scattered by pollution particles such as sulfates, nitrates, organic carbon compounds, soot, and soil dust. Visibility is a measure of how far and how well people can see into the distance. The term is used broadly to cover visibility, limits on the ability to view distant objects, as well as the more subjective issue of visual clutter, structures that intrude upon otherwise "pretty" scenes, as well as graffiti and other visual defacement. ![]() Visual pollution is an aesthetic issue, referring to the impacts of pollution that impair one's ability to enjoy a vista or view.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |