Revision: Pollution >> Pollution: A Rising Environmental Problem Biology (English Medium) ICSE Class 10 CISCE

Waste is any unwanted or undesired material or substance resulting from industliial, commercial mining, and agricultural operations, and from community activities.

Pollution is the addition of any such constituent to air, water or land which deteriorates the natural quality of the environment.

Pollutant is any such constituent which causes pollution.

Pesticides such as DDT (dichloro-diphenyl-trichloroethane) are used in agriculture to destroy pests, alter the basic structure of the soil, kill microorganisms in it, and may even reach the human body through food grown in such soils.

Sanitary landfills are places where waste is dumped in a ground depression and covered with dirt every day.

The contamination of soil by natural or synthetic substances that adversely affect its physical, chemical, and biological properties and reduce its productivity is called soil pollution.

The transfer of heat energy from one place to another via emission of EM energy (in a straight line with the speed of light) without heating the intervening medium is called radiation.

OR

The transfer of heat energy from one place to another via emission of EM energy (in a straight line with the speed of light) without heating the intervening medium is called radiation.

Noise is defined as any unpleasant, loud, undesired sound that interferes with one’s hearing and concentration, and the pollution caused by noise is termed noise pollution.

Noise is defined as any unpleasant/loud undesired sound interfering with one's hearing and concentration and the pollution caused due to noise is termed as noise pollution.

Noise pollution, also known as sound pollution, is defined as the presence of excessive, unwanted, or harmful sounds in the environment that disrupt normal activities and adversely affect the health and well-being of humans and other living organisms.

Statement: All bodies emit radiant energy depending on their temperature. The heat emitted (H) by a body is given by:

Where:

• σ = Stefan-Boltzmann constant
• e = Emissivity (for perfect radiator, e = 1)
• A = Area of the body
• T = Temperature (in Kelvin)

Key Points:

• Black bodies absorb and emit more radiant energy than bodies of lighter colors.
• Thermal radiation is partially reflected and partially absorbed when it falls on other bodies.

• When water is heated from the top, its density decreases, and it stays at the top. Since hot water cannot sink, convection does not occur and the bottom remains cool.
• Radiation is the transfer of heat without a medium — through electromagnetic waves.
• Heat from the Sun reaches us through radiation across the vacuum of space.
• All objects above 0 K emit thermal radiation (electromagnetic waves).
• Radiation is a two-step process: thermal energy → EM waves → thermal energy.
• Black or dark surfaces absorb more heat radiation; absorption also depends on the intrinsic properties of the substance.
• An infrared camera uses the radiation emitted by objects to see at night — useful for military surveillance.
• Copper is an excellent conductor; plastic is a bad conductor (insulator).
• Heat readily conducts through metals (copper and steel) but not through non-metals (wood and plastic).

• Noise pollution is an undesirable high level of sound. Included as an air pollutant under Air (Prevention and Control of Pollution) Act, 1981, amended in 1987.
• Sources - machines, transportation, construction sites, industries, festivals and public functions.
• Exposure to 150 dB or more causes permanent hearing loss. Other effects - sleeplessness, increased heartbeat, altered breathing, psychological stress and negative impact on the child's learning.
• Control measures - sound absorbent materials, muffling noise, and horn-free zones near schools and hospitals.
• Supreme Court banned loudspeakers at public gatherings after 10 pm. The government has rules against firecrackers and loudspeakers.

1. Acid rain forms when rainwater absorbs industrial gases like CO₂, SO₂, and nitrogen oxides, making it more acidic.
2. It harms soil and vegetation, corrodes buildings, damages monuments by reacting with calcium, and reduces visibility.
3. It also acidifies water bodies, endangering fish and aquatic life.
4. Soil pollution reduces soil fertility and nutrients.
5. Waste control is essential to protect soil health.

1. Greenhouse gases like CO₂ and methane trap heat in the atmosphere, preventing its escape and causing the greenhouse effect.
2. Increased burning of fuels and deforestation raise CO₂ levels, intensifying global warming.
3. Global warming results in rising temperatures, melting polar ice, higher sea levels, and reduced agricultural and fishery yields.

• Ozone layer — present in the stratosphere (12–15 km above Earth). Absorbs harmful UV radiation. Thickness measured in Dobson Units (DU).
• CFCs rise to the stratosphere → UV rays release Cl atoms → Cl acts as a catalyst → continuously degrades O₃ → forms ozone hole, particularly over the Antarctic region.
• Other ozone-depleting substances — SO₂, nitrogen oxides and methyl chloroform.
• UV-B (280–322 nm) — damages DNA, causes mutations, skin cancer, ageing and snow blindness/cataract. It can permanently damage the cornea.
• The Montreal Protocol was signed at Montreal, Canada, in 1987 (effective 1989) to control the emission of ozone-depleting substances.

1. Launched on 2nd October 2014, the Swachh Bharat Abhiyan aimed to promote cleanliness and hygiene across India, encouraging people not to litter.
2. Key goals included cleaning urban and rural areas, eliminating open defecation by building toilets, and ensuring their usage.
3. The mission also focused on creating effective systems for managing solid and liquid waste efficiently.