The Chapter explains the types of pollution and the measures to combat them. Additionally, there are some steps that we can take to improve our ecosystem.
Pollution is undesirable contamination of the physical, chemical, or biological traits of the air, the land, the water, or the soil. Polluting agents are those that result in an adverse shift.
Recommended: Study for your Exams with Safalta School online. We provide Preparation materials for Class 9-12 that can boost your preparations.
Students studying in CBSE Class 12 can access NCERT Class 12 Books Biology Chapter 16- Environmental Issues here.
Free Demo Classes
Register here for Free Demo Classes
If you take NCERT Books as references for the examinations, you would appreciate your decision as most of the questions that appear in board exams are from these books. You can keep the digital form of the book handy and learn from it without any time constraints.
You can access FREE E-BOOKS at Safalta to prepare yourself for your examinations and test your knowledge. These books are not just free of cost, but they are also packed with ample knowledge and information related to your studies.
FREE MOCK PAPERS are also available that can help you test your own yourself. These papers can help you prepare for your exams in a better way.
Here, you can learn the NCERT Class 12 Books Biology Chapter 16- Environmental Issues. Moreover, you can get the links for other Chapter 16s to download the links.
Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil. Agents that bring about such an undesirable change are called as pollutants. In order to control environmental pollution, the Government of India has passed the Environment (Protection) Act, 1986 to protect and improve the quality of our environment (air, water and soil).
16.1 AIR POLLUTION AND ITS CONTROL
Smokestacks of thermal power plants, smelters and other industries release particulate and gaseous air pollutants together with harmless gases, such as nitrogen, oxygen, etc. These pollutants must be separated/ filtered out before releasing the harmless gases into the atmosphere.
There are several ways of removing particulate matter; the most widely used of which is the electrostatic precipitator (Figure 16.1), which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant. It has electrode wires that are maintained at several thousand volts, which produce a corona that releases electrons. These electrons attach to dust particles giving them a net negative charge. The collecting plates are grounded and attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall. A scrubber (Figure 16.1) can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime. Recently we have realised the dangers of particulate matter that are very very small and are not removed by these precipitators. According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometers or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation, inflammations and damage to the lungs and premature deaths.
Automobiles are a major cause for atmospheric pollution atleast in the metro cities. As the number of vehicles increase on the streets, this problem is now shifting to the other cities too. Proper maintenance of automobiles along with use of lead-free petrol or diesel can reduce the pollutants they emit. Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases. As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water, and carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively. Motor vehicles equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst.
In India, the Air (Prevention and Control of Pollution) Act came into force in 1981, but was amended in 1987 to include noise as an air pollutant. Noise is undesired high level of sound. We have got used to associating loud sounds with pleasure and entertainment not realising that noise causes psychological and physiological disorders in humans. The bigger the city, the bigger the function, the greater the noise!! A brief exposure to extremely high sound level, 150 dB or more generated by take off of a jet plane or rocket, may damage ear drums thus permanently impairing hearing ability. Even chronic exposure to a relatively lower noise level of cities may permanently damage hearing abilities of humans. Noise also causes sleeplessness, increased heart beat, altered breathing pattern, thus considerably stressing humans.
Considering the many dangerous effects of noise pollution can you identify the unnecessary sources of noise pollution around you which can be reduced immediately without any financial loss to anybody? Reduction of noise in our industries can be affected by use of soundabsorbent materials or by muffling noise. Stringent following of laws laid down in relation to noise like delimitation of horn-free zones around hospitals and schools, permissible sound-levels of crackers and of loudspeakers, timings after which loudspeakers cannot be played, etc., need to be enforced to protect ourselves from noise pollution.
16.1.1 Controlling Vehicular Air Pollution: A Case Study of Delhi
The Government of India through a new auto fuel policy has laid out a roadmap to cut down vehicular pollution in Indian cities. More stringent norms for fuels means steadily reducing the sulphur and aromatic content in petrol and diesel fuels. Euro III norms, for example, stipulate that sulphur be controlled at 350 parts-per-million (ppm) in diesel and 150 ppm in petrol. Aromatic hydrocarbons are to be contained at 42 per cent of the concerned fuel. The goal, according to the roadmap, is to reduce sulphur to 50 ppm in petrol and diesel and bring down the level to 35 per cent. Corresponding to the fuel, vehicle engines will also need to be upgraded.
Mass Emission Standards (Bharat Stage II which is equivalent to Euro-II norms) are no more applicable in any of the cities of India. Details of the latest Mass Emission Standards in India are provided below (Table 16.1)
NCERT Class 12 Books Biology Chapter 16- Environmental Issues- PDF Download
Chapter 16: Environmental Issues
अध्याय 16: पर्यावरण के मुद्दे
Source: safalta.comSafalta provides the latest NCERT course books for all the major subjects of Class 12. A team of proficient teachers drafts these matters in a precise and thorough manner. You can download the PDFs for all the subjects in a Chapter 16-wise format.
These Books are very effective in preparing for annual exams. Here is the PDF for NCERT Class 12 Books Biology Chapter 16- Environmental Issues.
Where can you download NCERT Class 12 Books Biology Chapter 16 PDF?
What topics are covered in NCERT Class 12 biology Chapter `15?
- Air Pollution and Its Control
- Water Pollution and Its Control
- Solid Wastes
- Agro-chemicals and their Effects
- Radioactive Wastes
- Greenhouse Effect and Global Warming
- Ozone Depletion in the Stratosphere
- Degradation by Improper Resource Utilisation and Maintenance
Why should students study from NCERT Books Class 12 Biology for board exams?
Why are CBSE Books for Class 12 Biology so important?
To get outstanding marks, we provide mock test papers that can help gear-up your preparations for exams. Additionally, you can also download e-books to get yourself prepared even in a better way.