Introduction to Environmental Chemistry. Definition, Environment definition and segments, Layers of atmosphere

1. Environmental Chemistry

2. Definition
• Environmental chemistry is a branch of chemistry
• The study of the sources, reactions, transport and effects, and fates of
chemical species (atoms, molecules, ions, etc.) in water, soil, air, and
the living environmental, and the effects of human activity upon
these.
• Study of chemical processes occurring in the environment which are
impacted by humankind’s activities.
• For e.g. the ozone layer absorbing most of the Sun’s Ultraviolet (UV) radiation
and splitting into O2 from O3 is a chemical process. CFCs destroying the ozone
layer (effect of human activity)

3. Environment
• The word environment means “surrounding”.
• Environment means the surroundings that surrounds living beings
from all sides and affect their lives.
• Environment can be defined as one’s own surroundings including all
of the living (biotic) and non-living (abiotic) factors that act on
organism, population, or ecological community and influence its
survival and development

4. • Abiotic factors:-non-living components that influence population size
and the environment
• Physical conditions and non-living resources that affect living
organism in terms of growth and reproduction
• E.g. temperature, light intensity, carbon dioxide levels, pH of water
and soil
• Seasonal temperature variations affect when plants flower, when
animals breed, when seeds germinate and when animals hibernate.
• Many types of plants grow better when they are fully exposed to
sunlight
• For instance, the pH of the soil can have an effect on the types of
plants which can grow in it.

5. • Biotic factors: a living component that affects the population of
another organism, or the environment
• E.g. a prey is a biotic factors since it’s a living thing that could affect
the population of another organism (more prey = increase in
population and vice versa)
• Pathogens* are likely to cause a decrease in population
• Human building cities and factories and disposing of waste into the
water is affecting the environment.
• Pathogen: a bacterium, virus, or other microorganism that can cause disease.

6. Segments of Environment
1. Lithosphere: the earth crust* consisting of the soil and rocks. The
soil is made up of organic, inorganic matter and water. They are
responsible for the fertility of the soil and hence its productivity.
2. Hydrosphere: this comprises of all the surface and ground water
such as seas, oceans, lakes, streams, glaciers, polar ice caps, and the
water locked in minerals below earth crust. The uncommon
properties of water are mainly responsible for supporting terrestrial
and aquatic life one earth.
1. Crust: outermost layer of earth

7. 1) Biosphere: parts of Earth where life exists.
2) Atmosphere: layer of gases surrounding the planet. Oxygen is used
by most organisms for respiration; and carbon dioxide is used by
plants for photosynthesis.

8. Structure of the Atmosphere
• The atmosphere is broadly divided into four major zones
• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere.

9. Troposphere
• It is the region nearest to the ground
• Contains 70 % of atmospheric mass
• Temperature decreases with height.
• 15 C at sea level to -56.5 C at 11,000 m
• Contains 99% of the water vapor in the atmosphere
• Tropopause is the layer between troposphere and stratosphere

10. Stratosphere
• The region above troposphere
• Warmer layers higher and cooler layers closer to the Earth
• The increase in temperature is due to ozone absorbing UV rays from
the sun
• Ozone is present in the stratosphere

11. Mesosphere
• Region above stratosphere
• Temperature decreases with height
• Menopause is the layer between Mesosphere and Thermosphere, at
which is the coldest temperature (about -100 C)

12. Thermosphere
• It is the region above the Mesosphere
• Temperature increases with increasing height
• Atmospheric gases (oxygen and nitrogen) in this region absorb solar
radiation and undergo ionization.
• The region from 50-100 km is called ionosphere due to presence of
positive ions and electrons

13. Credits
• https://sciencing.com/do-abiotic-factors-affect-organisms-
8612318.html
• Quora.com
• https://www.nationalgeographic.org/encyclopedia/biosphere/
• Wikipedia.org