Some aerosols—like dust and pollen—are picked up naturally when the wind blows. But the air can also carry particles that cause air pollution, such as the soot, smoke, and other pollutants from car exhaust and power plants. When there are too many particles in the air, it can be difficult for plants and animals to breathe. People need to breathe, and so do lots of other animals—and plants! Breathing is part of a process called respiration. During respiration, a living thing takes in oxygen from the air and gives out carbon dioxide.
This process gives animals and plants the energy to eat, grow, and live life! When humans and animals breathe, we give off an odorless gas called carbon dioxide, or CO 2. Plants use this gas, along with sunlight, to make food—a process called photosynthesis. The mesosphere starts at 31 miles 50 km and extends to 53 miles 85 km high. The top of the mesosphere, called the mesopause, is the coldest part of Earth's atmosphere, with temperatures averaging about minus degrees F minus 90 C. This layer is hard to study.
Jets and balloons don't go high enough, and satellites and space shuttles orbit too high. Scientists do know that meteors burn up in this layer. The thermosphere extends from about 56 miles 90 km to between and miles and 1, km.
Temperatures can get up to 2, degrees F 1, C at this altitude. The thermosphere is considered part of Earth's atmosphere, but air density is so low that most of this layer is what is normally thought of as outer space. In fact, this is where the space shuttles flew and where the International Space Station orbits Earth. This is also the layer where the auroras occur. Charged particles from space collide with atoms and molecules in the thermosphere, exciting them into higher states of energy.
The atoms shed this excess energy by emitting photons of light, which we see as the colorful aurora borealis and aurora australis. The exosphere , the highest layer, is extremely thin and is where the atmosphere merges into outer space.
It is composed of very widely dispersed particles of hydrogen and helium. Earth is able to support a wide variety of living beings because of its diverse regional climates, which range from extreme cold at the poles to tropical heat at the Equator. Regional climate is defined by the University Corporation for Atmospheric Research as the average weather in a place over more than 30 years.
Air thins as you go up in altitude because the majority of air is held close to the earth's surface by gravity. As I said, there is no air in space. Space is almost a perfect vacuum, but gas and dust particles do float around out there. The medium that fills the space in the universe around the stars and galaxies is called Interstellar Medium. Some gases in the air come from volcanic eruptions. Volcanic eruptions eject gases from the interior of the Earth.
The most common gas emitted by volcanoes is water vapor. Other gases, such as carbon monoxide and sulfur dioxide , are toxic to most organisms. A few organisms, however, thrive on these gases. At the bottom of the ocean are bacteria that do not need oxygen or sunlight to survive. In other words, they do not need air. These strange organisms create their own nutrients using hydrogen sulfide , not carbon dioxide. The air is different as you move higher and higher into the atmosphere.
The air gets "thinner" as elevation climbs because there are fewer air molecules up there. Mountain climbers often have to use canisters of oxygen as they climb above 3, meters 12, feet because there is not enough oxygen in the atmosphere for most people to breathe. High mountains such as Mount Everest 8, meters, or 29, feet , in Nepal and China, are littered with empty oxygen canisters that climbers discard when they are used up. Ozone is made up of three atoms of oxygen.
The massive collection of these molecules is called the ozone layer. Unfortunately, air pollution has a negative effect on the air we breathe. Air pollution happens when harmful byproducts, like exhaust from cars, enter the air.
These pollutants can clog the atmosphere with smog , a combination of smoke and fog. They can also create toxic clouds of dust. Other air pollutants, such as methane and excess amounts of carbon dioxide, can upset the balance of molecules in the air, contributing to global warming. Non-Atmospheric Air Compressed air is air kept at a consistent pressure, such as air pressure at sea level.
Airplanes are usually pressurized at ground level so passengers can breathe without canisters of air. Often, compressed air is kept at a pressure higher than normal air pressure. Scuba divers use compressed air to breathe under water. The canisters of air allow divers to inhale through a tube and exhale into the water.
Pneumatics is the science and work of pressurized air and other gases. The uses for pneumatics are far-ranging. Air brakes in automobiles, trucks, and trains use compressed air to slow wheel rotation and stop the vehicles. Pipe organs use compressed air at different pressures to create different musical notes.
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