ESCI 100(Chemistry of the Atmosphere)

Atmosphere

• layer of gas or layer of gases that envelop a planet and is held in place by the gravity of the planetary body

• composed of about 78% nitrogen, 21% oxygen, and 1% of other gases.

Atmospheric Chemistry

study if the chemical process that occur in the Earth’s atmosphere and other planetary atmosphere

Layers of the Earth’s Atmosphere

1. Exosphere 

2. Thermosphere

3. Mesosphere

4. Stratosphere

5. Troposphere

Composition of Air

a mixture of gases which makes up the Earth’s atmosphere

Common Properties of Air

• Colorless and Odorless

• Occupy Space

• Air Exerts Pressure

• Expansion

Colorless and Odorless

has no color and odor, an invisible matter that can only be felt

Occupy Space

mixture of gases, occupies space

Air Exerts Pressure

has weight and pressure exerted by the weight of air known as AIR PRESSURE

Expansion

on heating it expands and occupies more space. The more it expand the thinner it becomes. Hence the pressure of the warm wind is lower than that of cold wind

Chemical Reaction in Atmosphere

process in which various chemical substances in Earth’s atmosphere interact and transform into different compounds

Different Chemical Reaction in Atmosphere

1. Combustion Reaction

2. Ozone Formation

3. Photochemical Smog Formation

4. Acid Rain Formation

5. Aerosol Formation

6. Greenhouse Gas Reaction

7. Nitrogen Oxides (Nox) Formation

8. Volatile Organic Compounds (VOCs) Reaction

9. Hydroxyl Radicals (OH) Reactions

10. Nitrogen Fixation

Combustion Reaction

substance burns in oxygen with the release of carbon dioxide, water and energy in the form of heat, light and even sound.

Ozone Formation

formed in the atmosphere through the series of reactions involving oxygen molecules and sunlight

Photochemical Smog Formation

mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds react to sunlight

Acid Rain Formation

• formed when pollutants, primarily sulfur dioxide, react with atmospheric moisture

• type of rain that contains high level of acidic components, primarily sulfur acid and nitric acid

Aerosol Formation

• “Aerosols” are tiny particles suspended in the atmosphere 

• Aerosols can be formed through various chemical reactions, including the oxidation of sulfur dioxide and nitrogen oxide to form sulfate and nitrate particles

Greenhouse Gas Reaction

“Greenhouse gas” are gases in the Earth’s atmosphere that trap heat

Nitrogen Oxides (Nox) Formation

• Nitrogen oxides (Nox), including nitric oxide (NO) and nitrogen dioxide (NO2), are produced through combustion process.

• These gases are involved in reactions that contribute to the formation of photochemical smog.

• Can also participate in the formation of acid rain.

• Both NO and NO2 are formed during high-temperature combustion in the atmosphere, when oxygen combines with nitrogen.

Volatile Organic Compounds (VOCs) Reaction

• “Volatile organic compounds” are organic compounds that have a high vapor pressure at room temperature.

• High vapor pressure correlates with a low boiling point, which relates to the number of the sample’s molecules in the surrounding air, a trait knows as “valatility”

Hydroxyl Radicals (OH) Reactions

• highly reactivate molecules present in the atmosphere

• removing pollutants from the atmosphere

• non-toxic to humans, animals, and plants

• kills bacteria, virus and mold

4 Types of Hydroxyl Radicals

1. Atmospheric

2. In-vivo

3. Chemical

4. Interstellar

Nitrogen Fixation

• vital process in which atmospheric nitrogen is converted into biologically useful forms, such as ammonia and nitrates

• essential for the availability of nitrogen in ecosystems and the growth of plants

Challenges in Atmospheric and its impact to Agriculture

1. Climate Change

2. Air Pollution

3. Ozone Depletion

4. Acid Rain

5. Stratospheric Jet Stream

6. Space Weather

7. Aerosol Loading

8. Deforestation

Climate Change

refers to long-term shifts in temperatures and weather patterns, mainly caused by human activities especially  burning of fossil fuels

Air Pollution

refers to contamination of the indoor outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere

Ozone Depletion

thinning of the ozone layer present in the upper atmosphere

Acid Rain

includes any form of precipitation with acidic components, such as sulfuric or nitric acid that fall to the ground from the atmosphere in wet or dry forms

Stratospheric Jet Stream

fast, narrow current of air flowing from the west to east that encircles the globe

Space Weather

refers to the variable conditions on the sun and in space

Aerosol Loading

suspensions of solids and/or liquid particles in the air that we breathe

Deforestation

removal of trees can disrupt the carbon cycle, affecting the atmosphere’s ability to absorb and store carbon dioxide.