module 1

• Importance of environmental science:

  • It is a multi-disciplinary science involving branches like chemistry, physics, medical science, life science, agriculture, public health, and sanitary engineering
• Environmental science studies physical phenomena in the environment, including the sources, reactions, transport, effects, and fate of physical and biological species in the air, water, and soil
• Environment is the sum total of all external forces, influences, and conditions affecting the life, nature, behavior, growth, development, and maturation of living organisms
• The atmosphere:

  • Comprises 78% nitrogen, 21% oxygen, and smaller amounts of argon, carbon dioxide, helium, and neon
  • Contaminants in the air include smoke, toxic gases, dust, ash from volcanoes, and salt
• Layers of the atmosphere:

  1. Troposphere:

  • Reaches 12 km from the Earth’s surface
  • Comprises roughly 80% of the weight of the atmosphere

  2. Stratosphere:

  • Reaches 50 km from the Earth’s surface
  • Contains the Ozone Layer

  3. Mesosphere:

  • Extends between 50 km and 70 km from the Earth’s surface
  • Coldest layer of the atmosphere

  4. Thermosphere:

  • Contains only 0.001% of the gases in the atmosphere
  • Hottest layer of the atmosphere

  5. Exosphere:

  • Outermost layer of the atmosphere
  • Extends as far as 6000 miles into space
• The hydrosphere:

  • Comprises all types of water resources like oceans, seas, lakes, rivers, streams, reservoirs, polar ice caps, glaciers, and groundwater
• World's water resources:

  • About 71% of the Earth's surface is water-covered, with oceans holding the majority of Earth's water
  • Freshwater resources are crucial for human consumption and other uses
• Of the freshwater on Earth, more is stored in the ground than in rivers and lakes, with most freshwater stored in glaciers and icecaps
• Ice caps, glaciers, and snow hold about 68.70% of freshwater, mainly in the Polar Regions and Greenland
• The lithosphere is the outer part of the solid earth, consisting of the crust (both oceanic and continental) and the outermost layer of the mantle, about 60 miles in thickness
• The biosphere indicates the realm of living organisms and their interactions with the environment, encompassing the atmosphere, hydrosphere, and lithosphere
• Environmental science integrates physical, biological, and information sciences to study the environment and solve environmental problems
• Environmental engineering applies science and engineering principles to improve the environment, providing healthful resources and remediating polluted sites
• Environmental engineering involves planning, designing, constructing, and operating equipment, systems, and structures to protect people from adverse environmental effects and improve environmental quality
• Ecosystems focus on the relationships and interactions of plants and animals with the water, air, and soil in their environment
• Environmental systems involve life interacting with abiotic components in the atmosphere, including the capture, movement, storage, and use of energy
• Importance of environmental science:

  • It is a multi-disciplinary science involving branches like chemistry, physics, medical science, life science, agriculture, public health, and sanitary engineering
• Environmental science studies physical phenomena in the environment, including the sources, reactions, transport, effects, and fate of physical and biological species in the air, water, and soil
• Environment is the sum total of all external forces, influences, and conditions affecting the life, nature, behavior, growth, development, and maturation of living organisms
• The atmosphere:

  • Comprises 78% nitrogen, 21% oxygen, and smaller amounts of argon, carbon dioxide, helium, and neon
  • Contaminants in the air include smoke, toxic gases, dust, ash from volcanoes, and salt
• Layers of the atmosphere:

  • Troposphere: reaches 12 km from Earth's surface, thinnest layer, comprises roughly 80% of the atmosphere's weight
  • Stratosphere: reaches 50 km from Earth's surface, location of the Ozone Layer
  • Mesosphere: extends between 50 km and 70 km from Earth's surface, coldest layer
  • Thermosphere: contains only 0.001% of the gases, hottest layer containing the Ionosphere
  • Exosphere: outermost layer extending as far as 6000 miles into space
• The hydrosphere:

  • Comprises all water resources like oceans, seas, lakes, rivers, polar ice caps, glaciers, and groundwater
  • 97% of Earth's water supply is in oceans, 2% in polar ice caps and glaciers, and 1% as fresh surface water
• Of the freshwater on Earth, much more is stored in the ground than is available in rivers and lakes
• More than half of freshwater is stored in the Earth, most within one-half mile of the surface
• Most freshwater is stored in the 7% of water found in glaciers and icecaps, mainly in the Polar Regions and in Greenland
• Water sources and their volumes:

  • Ice caps, Glaciers, & Snow: 5,773,000 cubic kilometers
  • Groundwater: 5,614,000 cubic kilometers
  • Fresh Lakes: 21,830 cubic kilometers
• The Lithosphere:

  • Etymology: Greek words: (1) “lithos” – rock, solid rock ; (2) “sphere” – ball, globe
  • The outer part of the solid earth consisting of the crust (both oceanic and continental) and the outermost layer of the mantle, about 60 miles (100 kilometers) in thickness
• The Biosphere:

  • Etymology: Greek words: (1) “bios” – life or living ; (2) “sphere” – ball, globe
  • Indicates the realm of living organisms and their interactions with the environment, via atmosphere, hydrosphere, and lithosphere
• Environmental Science:

  • Defined as the branch of biology focused on the study of the relationships of the natural world and the relationships between organisms and their environment
  • An interdisciplinary academic field that integrates physical, biological, and information sciences to study the environment and solve environmental problems
• Environmental Engineering:

  • The application of science and engineering principles to improve the environment (air, water, and/or land resources) and provide healthful water, air, and land for human habitation and other organisms
• Environmental Systems:

  • Ecosystem focuses on the relationships and interactions of plants and animals with the water, air, and soil that make up their environment
  • Sustainability is about maintaining ecosystems in the light of major depletion of natural resources