Composition of Earth's Atmosphere

Air is essential to life, yet we often take it for granted because it's so ubiquitous. But what exactly does air consist of? The Earth has two main atmospheres: troposphere and stratosphere. The troposphere is the lower part of our atmosphere where most weather occurs; it contains water vapor, carbon dioxide, nitrogen, oxygen, and argon, among other gases and particles. This region ranges from sea level up to approximately eight kilometers high over land areas. Above this lies the stratosphere which consists mostly of ozone with some remaining trace amounts of other elements like hydrogen fluoride.

Air also includes tiny solid particles called aerosols that range between one hundredth to ten thousand times smaller than the diameter of your hair. These can have an influence on climate change by reflecting light back into space and increasing cloud condensation nuclei. In addition, there are many different types of particles found naturally within Earth's atmosphere such as dust, pollen, volcanic ash, insect fragments, etc., all contributing to its overall makeup.

In terms of composition, human exhaled breath mainly comprises around 79% nitrogen, along with some oxygen and CO₂, while dog's breath is typically similar though slightly more acidic due to their diet being higher in protein. Nitrogen makes up nearly three quarters of the volume while oxygen comes second at just under twenty percent, followed closely behind by argon which accounts for almost nine tenths of one percent of total gas mixture. Water vapor represents less than half a tenth of one percent but still plays an important role in maintaining humidity levels necessary for proper respiration and moisture balance in plants.

Overall, air is complex but vital substance composed largely of nitrogen, oxygen, argon, and various other gases and particles that make up our planet's atmosphere. Without these components, life as we know it would cease to exist.