31 Years NEET Previous Year Questions: Environmental Issues - 1 (Old NCERT) - Bank Exams MCQ

The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in terms of Dobson units (DU).

In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness It is a painful eye condition caused by overexposure to ultraviolet (UV) light. Cornea sunburn results due to the effects of UV light on the cornea.

The various greenhouse gases are CO₂, CH₄, CFCs and N₂O. Excessive use o f fossil fuels is adding more CO₂ to atmosphere. This increase in concentration of greenhouse gases has led to considerable heating of earth leading to global warming. During the past century, the temperature of earth has increased by 0.6°C.

UV rays act on chlorofluorocarbons (CFCs) releasing active chlorine (Cl, CIO) which further reacts with ozone in sequential manner thereby converting it into oxygen.

• Lichens are composed of algae and fungi living together in a symbiotic relationship.
• Sulfur dioxide, is a pollutant which when mixed with rainwater or air can damage lichens and does not allow them to grow due to which they act as natural indicators of air pollution.
• Therefore the absence of lichens indicates that the area is heavily polluted with sulfur dioxide. 

The scrubber is an electrostatic precipitator in which the dirty air is cleaned by capturing gas like SO₂ and other oxides in water/lime spray (CaCO₃).

Illustration of Electrostatic Percipitator:

High value of BOD (Biochemical Oxygen Demand) indicates that water is highly polluted. BOD is a measure of the amount of oxygen that is consumed by microorganisms as they break down organic matter in water. The higher the BOD, the more polluted the water is because there is a greater demand for oxygen by the microorganisms.

Water with a high BOD may contain high levels of organic matter, such as plant and animal matter, as well as substances like sewage and industrial waste. These substances provide food for the microorganisms, which consume oxygen as they break them down. As a result, the oxygen levels in the water may drop, leading to a decrease in the amount of oxygen available for other aquatic life.

Water with a low BOD may be less polluted, as it may contain less organic matter and therefore have a lower demand for oxygen by the microorganisms. However, low BOD does not necessarily mean that the water is pure. Other factors, such as the presence of chemicals, heavy metals, and pathogens, can also affect the quality of the water.

The UN Conference of Parties on climate change in 2011, was held in Durban, South Africa. It aimed at decrease of pollutant emission.

Liver cancer is caused due to aflatoxin released by Aspergillus fungus and Vinyl chloride. UV-rays are not related with liver cancer.

This conference occured from 20 Nov to 8 December, 2012 to extend the life of the Kyoto Protocol at Doha in Qatar.

60 - 70% SO₂ and 20 - 30% NO₂ contribute in the acid rain

Eutrophication is the excessive growth of algae, plants, and animals in water bodies due to nutrient enrichment, particularly with nitrogen and phosphate.
There is a drastic decrease in oxygen replenishment inside water. Non-availability of oxygen results in the death of aquatic animals.

Joint forest management or JFM is a programme launched by the Government of India in 1988 and guidelines issued in 1990.
It aims at establishing the partnership between local communities and state forest departments.

The ozone layer or ozone shield refers to a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation.

Domestic sewage rich in organic waste leads to an increase in Biological Oxygen Demand, which leads to a decrease in D.O. (dissolved oxygen) which leads to the death of fishes.