What is Air

Earth is the most important terrestrial planet as it is home to life.
The current atmosphere is rich in oxygen and nitrogen, but this was not always the case.
Initially, Earth's atmosphere was likely similar to that of Venus and Mars, consisting of over 90% carbon dioxide.
The formation of rocks and oceans played a crucial role in reducing atmospheric carbon dioxide levels.
The emergence of plants through photosynthesis contributed to increasing oxygen levels, supporting life.

Air Definition: A mixture of liquid, gas, and solid components.
Air varies greatly depending on location — examples include dry air in Arizona and humid conditions in Florida.
Major components of air:
- Nitrogen: 78%
- Oxygen: Approximately 21%
- Argon: 1%
- Water vapor: About 0.4%
- Carbon dioxide: 0.04% (400 ppm)
- Neon: 0.0018%
The understanding of carbon dioxide's contribution to climate change is emphasized, noting its increase from about 300 ppm in 1960 to 400 ppm currently.

Humidity is a measure of the amount of water vapor in the air, typically averaging between 70-80% in certain areas.
Latent Heat: The energy absorbed or released when water changes states (ice to water, water to vapor).
Water as a Greenhouse Gas: Water vapor also contributes to the greenhouse effect.

Aerosols are tiny solid or liquid particles suspended in the atmosphere.
- Common Aerosols: Sea salt, soil, smoke, pollen, microorganisms, ash, and dust.
These particles affect cloud formation and can influence weather patterns and visibility.

Ozone is composed of three oxygen atoms (O3) and forms a layer in the stratosphere that absorbs harmful UV radiation from the sun.
Current concentration: Approximately 0.03 parts per million.
The ozone layer is vulnerable to certain chemicals that can deplete it, increasing the risk of skin cancer and other health issues related to UV exposure.
There has been progress in recovering the ozone layer thanks to international agreements and regulations.