20.1 - Earth’s Atmosphere

The process of photosynthesis produces oxygen as a key by-product.
- The photodecomposition of water vapor by UV light is another key source of oxygen.
The more reactive gases, such as ammonia and methane, have mostly vanished through time, and our atmosphere now primarily consists of oxygen and nitrogen gases.
Atmospheric nitrogen gas is transformed into nitrates and other compounds appropriate for uptake by algae and plants through biological and industrial nitrogen fixation, the conversion of molecular nitrogen into nitrogen compounds.
The troposphere, the layer of the atmosphere that contains roughly 80% of the total mass of air and virtually all of the atmosphere's water vapor, is the most active zone in terms of visible phenomena.
- The stratosphere, which is made up of nitrogen, oxygen, and ozone, is located above the troposphere.

20.2 - Phenomena in the Outer Layers of the Atmosphere

Solar flares are violent eruptions on the sun's surface that result in the ejection of a large number of electrons and protons into space.
- They interrupt radio transmission and produce stunning celestial light shows known as auroras.
The input of sunlight and electrons is oriented by the magnetic field of the Earth, so that the most auroral displays occur approximately 2000 kilometers in diameter in the north and south poles, in a doughnut formed zone.
- This phenomenon in the northern hemisphere has been given the name Aurora borealis. It is called aurora australis in the southern hemisphere.
At times, Solar particle numbers are so large that aurora from other parts of the earth are also visible.

20.3 - Depletion of Ozone in the Stratosphere

Natural mechanisms create and destroy ozone, resulting in a dynamic equilibrium that keeps ozone levels in the stratosphere constant.
The nitrogen oxides, or NOx, are a class of chemicals that can deplete stratospheric ozone.
If STP on earth were to compress all stratospheric ozone into a single layer, that layer would be only approximately 3 mm thick!
- Although the ozone level is very low in the stratosphere, solar radiation in 200 - 300 nm can be removed.
- It acts as our protection against UV radiation in stratosphere, causing skin cancer, genetic mutations and destruction of plants and other forms of vegetation.

20.4 - Volcanoes

Magma, or molten rock, comes to the surface and causes several forms of volcanic eruptions.
N2, CO2, HCl, HF, H2S, and water vapor are among the gases released into the atmosphere.
- Volcanoes are thought to be responsible for around two-thirds of the sulfur in the atmosphere.
The enormous strength of the volcanic eruption leads to the stratosphere with a sizeable amount of gas.
SO2 is oxidized into SO3, which in a series of complex mechanisms is eventually converted to sulfuric acid aerosols.
- These aerosols can also influence the climate in addition to ozone destruction in the stratosphere.

20.5 - The Greenhouse Effect

A polyatomic molecule can vibrate in several directions.
The so-called greenhouse effect describes the trapping of heat near Earth’s surface by gases in the atmosphere, particularly carbon dioxide
Following the death of plants and animals, their tissues are oxidized to CO2 and return to the atmosphere.
- Moreover, the atmospheric CO2 and carbonates in oceans and lakes are dynamically balanced.
The solar radiant energy received from Earth is distributed between 100 and 5000 nm over the wavelengths but many are focused between 400 and 700 nm, the visible area of the spectrum.
In contrast, wavelengths larger than 4000 nm (IR region), due to a far lower mean area temperature as compared to the sun, are typical for Earth's thermal radiation emitted by the Earth's surface.
- Water and carbon dioxide, but not nitrogen or oxygen, can absorb outgoing IR radiation

20.6 - Acid Rain

Some environmental chemists refer to the corrosion of stone caused by acid rain as "stone leprosy."
- Acid rain is harmful to plants and aquatic life.
- Smelting, or roasting, the ores—that is, heating the metal sulfide in the air to generate the metal oxide and SO2—is a common method of extracting the metals.
There are two approaches to reducing the impact of SO2 pollution.
- The most straightforward approach is to remove sulfur from fossil fuels before burning, although this is difficult to achieve technologically.
- Removing SO2 as it is generated is a less expensive but less efficient option.

20.7 - Photochemical Smog

Photochemical smog, which is created by the reactions of automotive exhaust in the presence of sunshine, is more well-known.
- The term "smog" was coined to characterize the haze of smoke and fog that blanketed London in the 1950s.
These gases are referred to as primary pollutants because they trigger a chain of photochemical processes that result in secondary pollutants.
The solar radiant energy received from Earth is distributed between 100 and 5000 nm over the wavelengths.
- Many are focused between 400 and 700 nm, the visible area of the spectrum.
Wavelengths larger than 4000 nm, due to a far lower mean area temperature as compared to the sun, are typical for Earth's thermal radiation emitted by the Earth's surface.
- Water and carbons dioxide, but not nitrogen or oxygen, can absorb outgoing IR radiation

20.8 - Indoor Pollution

Radon-222 is a radioactive isotope that emits.
- It creates radioactive polonium-214 and polonium-218 when it decays, which can accumulate to dangerous quantities in confined spaces.
- These solid radioactive particles can stick to dust and smoke in the air, which are ingested and deposited in the respiratory system.
Radon-decay products will stick to both tobacco tar deposits in the lungs and solid particles in cigarette smoke, which can be inhaled by both smokers and nonsmokers.
The first detailed studies of radon's effects on human health were carried out in the 1950s when it became apparent that the incidence of lung cancer in uranium miners was abnormally high.
- Certain scientists have called these studies into question as they were smokers too.
It seems very probably that the development of lung cancer will be affected synergistically by radon and smoking.
In the event of radon-decay products the solid cigarette smoke, which can be inhaled by smokers and non-smokers, will adhere not only to the tobacco tar deposits in the lungs.
- More systematic studies are needed to assess the impact of radon on the environment.

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Chemistry

Chapter 20 - Chemistry in the Atmosphere

20.1 - Earth’s Atmosphere

The process of photosynthesis produces oxygen as a key by-product.
- The photodecomposition of water vapor by UV light is another key source of oxygen.
The more reactive gases, such as ammonia and methane, have mostly vanished through time, and our atmosphere now primarily consists of oxygen and nitrogen gases.
Atmospheric nitrogen gas is transformed into nitrates and other compounds appropriate for uptake by algae and plants through biological and industrial nitrogen fixation, the conversion of molecular nitrogen into nitrogen compounds.
The troposphere, the layer of the atmosphere that contains roughly 80% of the total mass of air and virtually all of the atmosphere's water vapor, is the most active zone in terms of visible phenomena.
- The stratosphere, which is made up of nitrogen, oxygen, and ozone, is located above the troposphere.

20.2 - Phenomena in the Outer Layers of the Atmosphere

Solar flares are violent eruptions on the sun's surface that result in the ejection of a large number of electrons and protons into space.
- They interrupt radio transmission and produce stunning celestial light shows known as auroras.
The input of sunlight and electrons is oriented by the magnetic field of the Earth, so that the most auroral displays occur approximately 2000 kilometers in diameter in the north and south poles, in a doughnut formed zone.
- This phenomenon in the northern hemisphere has been given the name Aurora borealis. It is called aurora australis in the southern hemisphere.
At times, Solar particle numbers are so large that aurora from other parts of the earth are also visible.

20.3 - Depletion of Ozone in the Stratosphere

Natural mechanisms create and destroy ozone, resulting in a dynamic equilibrium that keeps ozone levels in the stratosphere constant.
The nitrogen oxides, or NOx, are a class of chemicals that can deplete stratospheric ozone.
If STP on earth were to compress all stratospheric ozone into a single layer, that layer would be only approximately 3 mm thick!
- Although the ozone level is very low in the stratosphere, solar radiation in 200 - 300 nm can be removed.
- It acts as our protection against UV radiation in stratosphere, causing skin cancer, genetic mutations and destruction of plants and other forms of vegetation.

20.4 - Volcanoes

Magma, or molten rock, comes to the surface and causes several forms of volcanic eruptions.
N2, CO2, HCl, HF, H2S, and water vapor are among the gases released into the atmosphere.
- Volcanoes are thought to be responsible for around two-thirds of the sulfur in the atmosphere.
The enormous strength of the volcanic eruption leads to the stratosphere with a sizeable amount of gas.
SO2 is oxidized into SO3, which in a series of complex mechanisms is eventually converted to sulfuric acid aerosols.
- These aerosols can also influence the climate in addition to ozone destruction in the stratosphere.

20.5 - The Greenhouse Effect

A polyatomic molecule can vibrate in several directions.
The so-called greenhouse effect describes the trapping of heat near Earth’s surface by gases in the atmosphere, particularly carbon dioxide
Following the death of plants and animals, their tissues are oxidized to CO2 and return to the atmosphere.
- Moreover, the atmospheric CO2 and carbonates in oceans and lakes are dynamically balanced.
The solar radiant energy received from Earth is distributed between 100 and 5000 nm over the wavelengths but many are focused between 400 and 700 nm, the visible area of the spectrum.
In contrast, wavelengths larger than 4000 nm (IR region), due to a far lower mean area temperature as compared to the sun, are typical for Earth's thermal radiation emitted by the Earth's surface.
- Water and carbon dioxide, but not nitrogen or oxygen, can absorb outgoing IR radiation

20.6 - Acid Rain

Some environmental chemists refer to the corrosion of stone caused by acid rain as "stone leprosy."
- Acid rain is harmful to plants and aquatic life.
- Smelting, or roasting, the ores—that is, heating the metal sulfide in the air to generate the metal oxide and SO2—is a common method of extracting the metals.
There are two approaches to reducing the impact of SO2 pollution.
- The most straightforward approach is to remove sulfur from fossil fuels before burning, although this is difficult to achieve technologically.
- Removing SO2 as it is generated is a less expensive but less efficient option.

20.7 - Photochemical Smog

Photochemical smog, which is created by the reactions of automotive exhaust in the presence of sunshine, is more well-known.
- The term "smog" was coined to characterize the haze of smoke and fog that blanketed London in the 1950s.
These gases are referred to as primary pollutants because they trigger a chain of photochemical processes that result in secondary pollutants.
The solar radiant energy received from Earth is distributed between 100 and 5000 nm over the wavelengths.
- Many are focused between 400 and 700 nm, the visible area of the spectrum.
Wavelengths larger than 4000 nm, due to a far lower mean area temperature as compared to the sun, are typical for Earth's thermal radiation emitted by the Earth's surface.
- Water and carbons dioxide, but not nitrogen or oxygen, can absorb outgoing IR radiation

20.8 - Indoor Pollution

Radon-222 is a radioactive isotope that emits.
- It creates radioactive polonium-214 and polonium-218 when it decays, which can accumulate to dangerous quantities in confined spaces.
- These solid radioactive particles can stick to dust and smoke in the air, which are ingested and deposited in the respiratory system.
Radon-decay products will stick to both tobacco tar deposits in the lungs and solid particles in cigarette smoke, which can be inhaled by both smokers and nonsmokers.
The first detailed studies of radon's effects on human health were carried out in the 1950s when it became apparent that the incidence of lung cancer in uranium miners was abnormally high.
- Certain scientists have called these studies into question as they were smokers too.
It seems very probably that the development of lung cancer will be affected synergistically by radon and smoking.
In the event of radon-decay products the solid cigarette smoke, which can be inhaled by smokers and non-smokers, will adhere not only to the tobacco tar deposits in the lungs.
- More systematic studies are needed to assess the impact of radon on the environment.