presentation on atmosphere and its composition and Air polution in ppt
- 1. ATMOSPHERE Composition and Pollution By Storm Breakers (Group 1) Department: BS Biotechnology
- 2. Atmosphere of Earth: • The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity. • The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night . • The study of Earth's atmosphere and its processes is called atmospheric science (aerology).
- 3. Composition
- 5. The Vertical Structure of the Atmosphere
- 6. Troposphere • Surface to roughly 10 km . • 3/4 of mass of atmosphere in this layer. • Most weather occurs in this layer. • Temperature generally decreases with height in this layer (by 6.5C per km, 3.6 F per 1000 ft). • The top of troposphere is called the tropopause. Jet stream tends to be strongest near the tropopause. • Above the tropopause is the stratosphere.
- 7. Stratosphere • 10-50 km above the surface • Temperature constant or INCREASING with height. • Stable (not a lot of vertical mixing ) and dry. • It contains the ozone layer.
- 8. Why constant temperature and warm with height in stratosphere? • Absorption of solar radiation by the stratospheric ozone layer.
- 9. Stratospheric Ozone Layer • Maximum ozone (O3) between 20 and 30 km. • Protects the surface from harmful ultraviolet (UV) radiation. • Ozone is produced photo -chemically. • Ozone is depleted by Chlorofluorocarbons.
- 11. Mesosphere • Occupy the region above the stratosphere and below the thermosphere. • Extends from the stratopause at an altitude of about 50 km to the mesopause at 80–85 km. • It is the coldest place on Earth and has an average temperature around −85 degree Centigrade. • The mesosphere is also the layer where most meteors burn up upon atmospheric entrance. • The noctilucent clouds are formed here .
- 13. Thermosphere • 80-400km • Region of warming with height because of absorption of radiations by Ozone. • This layer is completely cloudless and free of water vapor. However, non-hydrometeorological phenomena such as the aurora are occasionally seen .
- 15. Exosphere • The outermost layer of Earth's atmosphere. • It extends from the exobase, which is located at the top of the thermosphere at an altitude of about 700 km above sea level, to about 10,000 km where it merges into the solar wind. • The exosphere contains most of the satellites orbiting Earth.
- 17. AIR POLLUTION • Air pollution occurs when harmful or excessive quantities of substances including gases, particulates, and biological molecules are introduced into Earth's atmosphere.
- 18. Pollutants • Pollutant is a substance or energy introduced into the environment that has undesired effects. • Primary pollutants are injected into the atmosphere directly. • For Example CO, CO2, NO and NO2 etc. • A secondary pollutant is not directly emitted as such, but forms when other pollutants (primary pollutants) react in the atmosphere. • For example Ozone , PANs , H2SO4 etc
- 20. Outdoor Air Pollution • Major outdoor air pollution is concerned to Smog Acid Rain Ozone
- 21. SMOG • Combination “SM” from smoke and “OG” from fog. • Smoke + Sulfur dioxide combine with fog to create industrial smog. • When Primary pollutants interact under the influence of sunlight to produce a mixture of hundreds of different and hazardous chemicals known as secondary pollutants is called photochemical smog. • Conditions for photochemical smog; • Sunlight , Temperature greater than 18 degrees Celsius . • The Production of oxides of Nox. • The production of VOCs.
- 23. ACID RAIN