The amount of energy consumed by a country depends on the living standards of its citizens and the degree of its industrialization. The average energy required for a man to maintain his daily activities require about 20 k cal per day. At present, the global energy consumption per capita per day is about 2000 times the 20 K calorie he needs for maintaining life. The figure shows the global energy consumption from 1900 to 1990.
At present, about 40% of demand for energy in the world is obtained from oils. Similarly, about 20% of the total energy consumption provided by coal, about 20% by natural gas, wool 10%, nuclear resources 7% and hydroelectric power 3%. Remaining required energy is fulfilled by the resources like solar energy, tidal energy, wind energy etc.
In Nepal, existing energy sources are classified into two major groups:
Nepal is not an industrially developed country. So that biomass energy as the burning of wood, agricultural waste products, and animal waste are the important resources of energy. About 94% of the total energy consumption of the country is met from biomass, out of which 80% is met by burning wool and 8.5% from animal waste.
Pollution is the addition of something in the ecosystem, which has a detrimental effect on the environment. Odum (1971) defined pollutants as an undesirable change in the physical-chemical and biological activities. Air containing dust, smoke and CO2 makes air polluted. Likewise, the high concentration of chemical fertilizer such as nitrogen, phosphorous and potassium in the soil pollutes the land.
An undesirable change in the physical, chemical or biological characteristics of air is called pollution. The substances which pollute the air called pollutants.
Sources of air Pollution
Control of Air Pollution
Effects of Air pollution
Degradation in the quality of water is called water pollution. Water covers over the 3/4th part of the earth’s surface. It is a very important resource for people and the environment. Water pollution affects drinking water, rivers, lakes and oceans all over the world. In many developing countries, it is usually a leading cause of death, by people drinking from polluted water sources. Drainage and wastage from industries, laboratory, hospitals, and homes are the main factors that cause water pollution.
Causes of water pollution
There are various causes of water pollution. Main causes of water pollution are described below:
Control of Water Pollution
Effects of water pollution
Manu Kumar Khatry, Manoj Kumar Thapa, et al.Principle of Physics. Kathmandu: Ayam publication PVT LTD, 2010.
S.K. Gautam, J.M. Pradhan. A text Book of Physics. Kathmandu: Surya Publication, 2003.
Pollution is the addition of something in the ecosystem, which has a detrimental effect on the environment.
An undesirable change in the physical, chemical or biological characteristics of air is called pollution.
At present, about 40% of demand for energy in the world is obtained from oil only.
In many developing countries, it is usually a leading cause of death, by people drinking from polluted water sources..