Mechinopedia For Mechanical Engineers

The atmosphere has several built-in self cleaning processes such as dispersion, Gravitational settling, flocculation, absorption, rain washout and so on, to cleanse the atmosphere. In terms of  a long range control of air pollution, control of  contaminants at their source is more desirable and effective method  through preventive or control technologies. 1. Source Control :  Since we know the substances that causes air pollution, the first approach to its control will be through source reduction. Some actions that can be taken in this regard as follows:  a) Use only unleaded petrol b) Use petroleum products and other fuels that have low Sulphur and ash content.  c) Reduce the number of  private vehicles on the road by developing an efficient public -transport system and encouraging people to walk or use cycles.  d) Ensure that houses, schools, restaurants and places where children play are not located on busy streets.  e.) Plant trees along busy streets because they remove particulate

HYDROCARBONS : COMMON POLLUTANT  Hydrocarbons Especially lower hydrocarbons get accumulated due to the decay of vegetable matter.  Human Sources ( causes ) :  Agriculture, decay of  plants, burning of wet logs.  Health Effects :  Carcinigenic. Environmental effect :  It produces an oily filmy on the surface and do not as such causes a serious problem until they react to form  secondary pollutants. Ethylene causes plant damage even at low concentrations. 

  OZONE (O3) : COMMON POLLUTANT :  Highly reactive irritating gas with an unpleasant odor that forms in the troposphere. It is a major component of photochemical smog.   Human Sources ( Causes ) :  Chemical reaction with volatile organic compounds ( emitted mostly by cars and industries ) and nitrogen oxides.  Environmental Effect : Moderates the Climate. 

SUSPENDED PARTICULATE MATTER : COMMON POLLUTANT  It includes variety of particles and droplets (aerosols). They can be suspended in atmosphere for short   periods to long periods.  Human Sources (Causes) :  Burning Coal in power and industrial plants ( 40% ), burning diesel and other fuels in vehicles (17%), agriculture, unpaved roads, construction etc.,  Health effects : ' Nose and throat irritation, lung damage, bronchitis, asthma, reproductive problems and cancer.  Environmental Effects : Reduces visibility, acid deposition and H2SO4 droplets can damage trees, soils and aquatic life in lakes.

SULPHUR DI OXIDE (SO2) : COMMON POLLUTANT  It is a colorless and irritating gas. It is formed mostly from the combustion of Sulphur containing fossil fuel such as coal and oil. In the atmosphere it can be converted to sulphuric acid ( H2SO4) which is a major component of acid deposition .  Human Resources ( Causes) :  Coal Burning in Power plants (88%) and  industrial processes ( 10%)  Health Effects :  Breathing problems of healthy people  Environmental Effects :  Reduce Visibility, acid deposition of H2SO4 can damage trees, soil and aquatic life in lakes.

NITROGEN DI OXIDE : COMMON POLLUTANT  It is reddish brown irritating gas that gives photochemical smog. In the atmosphere it can be converted into nitric acid (HNO3).  NO2 + Moisture (H2O) ----------------> HNO3  Human Resources (causes) :  Fossil Fuel burning in motor vehicles (49%) and power industrial plants  (49%).  Health Effects :  Lung Irritation and Damage.  Environmental Effects : Acid deposition of  HNO3 can damage trees, soils and aquatic life in lakes, HNO3 can corrode metals and eat away stone on buildings, statues and monuments. NO2 can damage fabrics. 

Carbon monoxide (CO) : Common air pollutant Description :  It is colourless, odourless and is poisonous to air-breathing animals. It is formed during the incomplete combustion of carbon containing fuels.  2C +  O2 ---------> 2CO  Human Resources (causes) : Cigarette smoking, incomplete burning of fossil fuels. About 77%  comes from motor vehicle exhaust.  Health Effects : Reacts with hemoglobin in red blood cells and reduces the ability of the blood to bring oxygen to body cells and tissues, which causes head aches and anemia. At high levels it causes coma, irreversible brain cell damage and death.  Environmental Effects : It increases the globe temperature.   

Air pollution may be defined as, "the presence of one or more contaminants like dust, smoke, mist and odor in the atmosphere which are injurious to human brings, plants and animals" . Rapid industrialization, fast urbanization, rapid growth in population, drastic increase in vehicles on the roads and other activities of human beings have disturbed the balance of natural atmosphere.  Sources of Air Pollution :  Sources of Air Pollution are of two types 1. Natural Resources : Examples - Volcanic eruptions, forest fires, biological decay, pollen grains, marshes, radioactive materials etc.  These pollutants are caused by Natural Resources. 2. Man-made Activities :  Examples -   Thermal Power plants, vehicular emissions, fossil fuel burning, agricultural activities etc.,  Classification Of  Air Pollutants : Depending upon the form (origin) of pollutants present in the environment, they are classified as , i) Primary Air Pollutants.  ii) Secondary Air Pollutants.  1. Primary Air

Environmental pollution may be defined as, "the unfavorable alteration of our surroundings". It changes the quality of air, water and land which interferes with the health of humans and other life on earth.  Pollution are of different kinds depending on the nature of pollutant generated from different sources.  1. Biodegradable Pollutants :  Biodegradable Pollutants decompose rapidly by Natural Processes. 2. Non - Bio degradable Pollutants :  Non - degradable pollutants do not decompose or decompose slowly in the environment.  Slowly decomposed materials are more dangerous because it is more difficult to remove them. Classification Of Pollution :  1. Air - Pollution  2. Water Pollution  3. Soil Protection  4. Marine Pollution  5. Noise Pollution  6. Thermal Pollution  7. Nuclear Hazards    

More current data is available on Internet. Important on-line learning Center : 1. www.mhhe.com / environmental science  2. Multimedia Digital Content Manager ( DCM ) in the form of  CD - ROM. Applications of  Internet in Environmental Protection :  1. These on-line learning Centre provides the current and relevant Information on, principles, problems, queries, application of environmental science. 2. It has digital files of photos, power-point lecture presentations, animations, web - exercises and quiz. These are useful to both students and teachers of environmental studies. 

1. Satellite data helps in providing correct and reliable information about forest cover. 2. It also provide information of atmospheric phenomena like monsoon, ozone layer depletion, smog, etc.,  3. From the Satellite data many new reserves of oil, minerals, can be discovered. 

GIS is a Technique of super imposing various thematic maps using digital data on a large number of  inter- related aspects. Applications Of  GIS :   1. Different thematic maps containing digital information on various aspects like water resources, soil type, forest land, cropland, grassland are super imposed on a layered form in computer using software. 2. Interpretations of  Polluted zones, degraded lands can be made based on GIS. 3. GIS can be used to check unplanned growth and related environmental problems.   

Data base is the collection of  inter - related data on various subjects. In the computer the information of   data base is arranged in a systematic manner that is easily manageable and can be very quickly retrieved. Applications Of  Database : a) The Ministry of  Environment and Forest : i) They are compiling a database on various biotic communities. ii) Database is also available for diseases like HIV / AIDS,  Malaria,  Fluorosis, etc.,  b) National management Information System (NMIS) :  They compiled a database on R & D projects along with information about research scientists and personnel involved. c) Environmental Information System (ENVIS) : It functions in 25 centres all over the country. They generate a network of  database in areas like pollution control, clean technologies, remote sensing, biodiversity, environmental management, desertification etc.,    

Remote Sensing refers to any method, which can be used to gather information about an object without actually coming in contact with it. Any force field like acoustic, gravity, magnetic, electromagnetic, etc., could be used for remote sensing, covering various disciplines extending from laboratory testing to astronomy. At present the term "remote sensing" is used more commonly to denote identification of earth feature by detecting the characteristics electromagnetic radiation that is reflected/emitted by the earth.  Remote Sensing System for Resource management  Remote Sensing data ( Image) have been used to derive thematic information on various natural resources and environment. This type and level of information Extracted depends on the expertise of the analyst and what he is looking in the data.  Examples -  The remote image of the land can be used to derive information of vegetative cover, water bodies, land use, pattern, geological Features, soil etc.,  Applications Of