Environment-3 Flashcards
what is ozone
it is a 3-oxygen molecule which is essentially poisonous to us.
what is the ozone layer where is it found?
Ozone layer is a layer of the earth’s atmosphere in which most of the atmosphere’s ozone is concentrated. Ozone is present in stratosphere part of the atmosphere i.e. 20- 30 km above the earth.
how is ozone formed ?
Ozone at the higher levels of the atmosphere is a product of UV
radiation acting on oxygen (O2) molecule. The higher energy UV
radiations split apart some moleculer oxygen (O2) into free oxygen (O)
atoms. These atoms then combine with the molecular oxygen to form
ozone as shown—
O O+O 2 ⎯ → ⎯⎯UV
OO O 2 3
Ozone)
what is ozone layer depletion and ozone hole?
Ozone layer depletion is the reduction in the concentration of ozone in the ozone layer. Thus, the ozone layer in the atmosphere becomes thinner and gets depleted allowing more ultraviolet rays to pass
through it. This phenomenon is referred as the Ozone hole.
what is the main reason for holes in the ozone layer
The foremost is the use of synethic chemicals called chlorofluorocarbons (CFCs) used in refrigerants and extinguishers. The other factor responsible for ozone destruction is the
pollutant nitrogen monoxide (NO).
When the harmful chemicals like chlorofluorocarbons (CFCs) are released into the air, it accumulates in the upper
atmosphere and reacts with ozone resulting in reduction in thickness of the ozone layer.
function of ozone layer
However, at the higher levels of the
atmosphere, ozone performs an essential function. It shields the surface
of the earth from ultraviolet (UV) radiation from the Sun
why is ozone very important to us?
Ozone layer is very important because it absorbs most of the ultraviolet rays of the sun and prevents it from reaching the surface. The ultraviolet rays can have many adverse impacts on humans, animals and plants. For ex: ultraviolet rays can cause skin cancer. They also damage the eyesight by cuaisng a disease called cataract. They also damage the immune sytem lowering our resistance to many diseases.
what is montreal protocol
The Montreal Protocol (an international treaty in Canada, 1987) was signed to control the emission of ozone
depleting substances. Subsequently many more efforts have been made and protocols have been laid down to
define roadmaps, separately for developed and developing countries, for reducing the emission of CFCs and other
ozone depleting chemicals.
what has unep done
In 1987, the United Nations Environment Programme
(UNEP) succeeded in forging an agreement to freeze CFC production at
1986 levels.
how can we reduce
-repair and maintain aircons and refridgerator
- do not use sprays, aerosols
-use eco friendly cleaning products
-rduce use of car
what are environmental problems caused due to human
(i) Pollution due to mismanagement of waste disposal.
(ii) Depletion of the Ozone Layer.
what is waste material
Unwanted or unusable materials which are discarded after primary use, or is worthless, defective
and of no use.
differentiate between bio-degradable and nonbio-degradable waste material
Biodegradable Wastes: Substances which can be decomposed by the action of micro-organisms are called as
biodegradable wastes. e.g., fruit and vegetable peels, cotton, jute, cow-dung, paper, etc.
(b) Non-biodegradable Wastes: Substances which cannot be decomposed by the action of micro-organisms are called
as non-biodegradable wastes. e.g., plastic, polythene, metals, synthetic fibres, radioactive wastes, pesticides, etc
what are different methods of waste disposal
(a) Biogas Plant: Biodegradable waste can be used in biogas plant to produce biogas and manure.
(b) Sewage Treatment Plant: The drain water can be cleaned in sewage treatment plant before adding it to rivers.
(c) Land Fillings: The wastes are buried in low lying areas and are compacted by rolling with bulldozers.
(d) Composting: Organic wastes are filled in a compost pit and covered with a layer of soil, after about three months,
garbage changes to manure.
(e) Recycling: Non-biodegradable waste are recycled to make new items.
(f) Reuse: It is a conventional technique to use an item again e.g., newspaper for making envelops.
why are biodegradable and non biodegradable put in diff bins
Biodegradable and non-biodegradable wastes should be discarded in two different dustbins. It is because:
(i) It saves time/ energy in segregation.
(ii) Biodegradable items can be sent directly for composting.
(iii) Non-biodegradable items can be sent for an appropriate reuse/recycle.
