Noise pollution is unwanted or harmful sound that intrudes upon human or other faunal activity. Noise pollution is almost entirely human generated, whether by machine sources or amplified sound of human creation. Approximately ninety percent of all such intrusive sound arises from such transport devices as motor vehicles, aircraft and rail activities. Noise pollution gives rise to an assortment of adverse human health effects as well as disruption of faunal activity. Regulation of noise pollution began in a systematic way in the United States with enactment of the Noise Control Act of 1972. Within the next 22 years a number of other national governments had emulated the U.S. initiative, including Netherlands (1979), France (1985), Spain (1993), and Denmark (1994). Noise pollution can also occur underwater, where man made sound may disrupt communication and echo-location for marine mammals and other fauna.
In the Arctic, people frequently see unique and beautiful optical phenomena. The atmospheric conditions that can lead to the development of these...
UrbanizationLast Updated on 2014-06-29 18:43:46Urbanization refers to a process whereby the building intensity of a high density human population increases or the number of people living in an urban area increase. Globally, this process has been on the rise for centuries; however, it has accelerated since the Industrial Revolution and was boosted again especially during the second half of the 20th century. The urbanization process was fueled mainly by migration from rural areas. The process usually comes to its end when urban population reaches a level of 80 to 90 percent of the total population of a country. Most developed countries reached this stage during the 20th century. Currently, at the beginning of the 21st century, urbanization is on the rise in most developing and less developed countries (Figure 1).
Despite the fact that the urbanization process in any country may come to a leveling off, the growth of urban population... More »
Fish sensesLast Updated on 2014-06-20 15:24:54Fish senses include a variety of mechanisms including light, chemicals, vibrations, and electricity. Successful faunal survival in any environment depends upon an organism's ability to acquire information from its environment through its senses. Fish have many of the same senses as humans; they can see, smell, touch, feel, and taste. Furthermore, they have developed some senses that humans lack, such as electroreception.
Photoreception, the ability to detect light, is necessary for vision. Fish have a very keen sense of vision, which helps them to find food, shelter, mates, and avoid predators. Fish vision is on par with human vision; many fish can see in color, and some can see in extremely dim light.
Fish eyes are different from human eyes. Their lenses are perfectly spherical, which enables them to see underwater because it has a higher refractive index to help them focus.... More »
Nonpoint sourceLast Updated on 2013-05-23 00:00:00
A nonpoint source refers to a source of pollution from an origin other than a well defined point. The term is most often applied to air pollution, water pollution and noise pollution. Nonpoint pollution sources may be classified as either line sources, area sources, or less frequently as volume sources. The classic line source is a linear highway, which produces both air pollution and noise pollution. A classic area source is a parcel of land, which produces water pollution in the form of surface runoff containing excessive amounts of nitrates, phosphates, pesticides and herbicides.
The attention to nonpoint sources was heightened, when researchers realized that most human exposure to air and noise pollution derived from nonpoint sources. In the case of noise pollution, over ninety percent of environmental noise exposure worldwide arises from line sources .Less commonly,... More »
UK Department for Environment, Food and Rural AffairsLast Updated on 2012-04-30 00:00:00
The Department for Environment, Food and Rural Affairs (Defra) is the government department responsible for environmental protection, food production and standards, agriculture, fisheries and rural communities in the United Kingdom (UK). Formal agreements also establish the frameworks for co-operation between Defra and the Scottish Government, the Cabinet of the National Assembly for Wales and with representatives from the Northern Ireland Assembly, which have delegated responsibilities for these matters in their respective nations.
Defra also represents the UK at the European Union on agricultural, fisheries and environment matters and in other international negotiations on sustainable development and climate change, although a new Department of Energy and Climate Change was created in 2008 to take over this responsibility.
The headquarters of Defra are... More »
Atmospheric lapse rateLast Updated on 2011-10-16 00:00:00
The atmospheric lapse rate ( ) refers to the change of an atmospheric variable with a change of altitude, the variable being temperature unless specified otherwise (such as pressure, density or humidity). While usually applied to Earth's atmosphere, the concept of lapse rate can be extended to atmospheres (if any) that exist on other planets.
Lapse rates are usually expressed as the amount of temperature change associated with a specified amount of altitude change, such as 9.8 °Kelvin (K) per kilometer, 0.0098 °K per meter or the equivalent 5.4 °F per 1000 feet. If the atmospheric air cools with increasing altitude, the lapse rate may be expressed as a negative number. If the air heats with increasing altitude, the lapse rate may be expressed as a positive number.
Understanding of lapse rates is important in microscale air pollution dispersion... More »
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