The following points highlight the three main components of biosphere. The components are: 1. Hydrosphere2. Atmosphere3. Lithosphere.

The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth'sgravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen,^] 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air content and atmospheric pressure vary at different layers, and air suitable for use in photosynthesis by terrestrial plants and breathing ofterrestrial animals is found only in Earth's troposphere and in artificial atmospheres.

The atmosphere has a mass of about 5.15×10¹⁸ kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km (62 mi), or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layerscan be distinguished in the atmosphere, based on characteristics such as temperature and composition.

The study of Earth's atmosphere and its processes is called atmospheric science (aerology). Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann

The three major constituents of air, and therefore of Earth's atmosphere, are nitrogen, oxygen, and argon. Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by volume in the coldest portions of the atmosphere to as much as 5% by volume in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor). The remaining gases are often referred to as trace gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other chemical compounds. Many substances of natural origin may be present in locally and seasonally variable small amounts as aerosols in an unfiltered air sample, including dust of mineral and organic composition, pollen andspores, sea spray, and volcanic ash. Various industrial pollutants also may be present as gases or aerosols, such as chlorine (elemental or in compounds),fluorine compounds and elemental mercury vapor. Sulfur compounds such as hydrogen sulfide and sulfur dioxide (SO₂) may be derived from natural sources or from industrial air pollution.

Major constituents of dry air, by volume^[6]
Gas	Volume^(A)
Name	Formula	in ppmv^(B)	in %
Nitrogen	N2	780,840	78.084
Oxygen	O2	209,460	20.946
Argon	Ar	9,340	0.9340
Carbon dioxide	CO2		0.04
Neon	Ne	18.18	0.001818
Helium	He	5.24	0.000524
Methane	CH4	1.79	0.000179
Not included in above dry atmosphere:
Water vapor^(C)	H2O	10–50,000^(D)	0.001%–5%^(D)
notes: ^(A) volume fraction is equal to mole fraction for ideal gas only, also see volume (thermodynamics) ^(B) ppmv: parts per million by volume ^(C) Water vapor is about 0.25% by mass over full atmosphere ^(D) Water vapor strongly varies locally

Structure of the atmosphere

Principal layers

In general, air pressure and density decrease with altitude in the atmosphere. However, temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions (see the temperature section, below). Because the general pattern of the temperature/altitude profile is constant and measurable by means of instrumented balloon soundings, the temperature behavior provides a useful metric to distinguish atmospheric layers. In this way, Earth's atmosphere can be divided (called atmospheric stratification) into five main layers. Excluding the exosphere, Earth has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere.^[8] From highest to lowest, the five main layers are:

· Exosphere: 700 to 10,000 km (440 to 6,200 miles)

· Thermosphere: 80 to 700 km (50 to 440 miles)^[9]

· Mesosphere: 50 to 80 km (31 to 50 miles)

· Stratosphere: 12 to 50 km (7 to 31 miles)

· Troposphere: 0 to 12 km (0 to 7 miles)

Earth's atmosphere Lower 4 layers of the atmosphere in 3 dimensions as seen diagonally from above the exobase. Layers drawn to scale, objects within the layers are not to scale. Aurorae shown here at the bottom of the thermosphere can actually form at any altitude in this atmospheric layer

Exosphere

The exosphere is the outermost layer of Earth's atmosphere (i.e. the upper limit of the 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 (6,200 mi; 33,000,000 ft) where it merges into the solar wind.

This layer is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide closer to the exobase. The atoms and molecules are so far apart that they can travel hundreds of kilometers without colliding with one another. Thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space. These free-moving particles follow ballistic trajectories and may migrate in and out of the magnetosphere or the solar wind.

The exosphere is located too far above Earth for any meteorological phenomena to be possible. However, the aurora borealis and aurora australis sometimes occur in the lower part of the exosphere, where they overlap into the thermosphere. The exosphere contains most of the satellites orbiting Earth.

2. Variations in constituents such as ozone and aerosols affect air quality, weather and climate. Atmospheric composition is central to Earth system dynamics because the atmosphere integrates spatially varying surface emissions globally on time scales from weeks to years. NASA works to provide monitoring and evaluation tools to assess the effects of climate change on ozone recovery and future atmospheric composition, improved climate forecasts based on the understanding of the forcings of global environmental change, and air quality modeling that take into account the relationship between regional air quality and global climate change. Achievements in these areas via advances in observations, data assimilation, and modeling enable improved predictive capabilities for describing how future changes in atmospheric composition affect air quality, weather, and climate. NASA draws on global observations from space, augmented by suborbital and ground-based measurements to address these issues.

3.Ecological disaster zone of Kazakhstan.

Some parts of our country in consequence with the use of nuclear weapon and other deleterious climatic influences were recognized as zones of radiation or ecological disaster. Citizens who lived in these regions get different supports in social and medical spheres Некоторые части нашей республики вследствие применения ядерного оружия и другconsidered by legislation.