Oxygen. The very chemical compound that we, as living beings breathe to live. Humans can survive about two weeks without food, almost 3 days without water but it can take as little as 3 minutes without air to die. The existence of air is essential but the quality of air is important as well. Poor air quality may contain high levels of compounds such as carbon, nitrogen, toxic fumes, etc. All of these does not come from out of nowhere but rather have various sources and are primarily fueled by human processes such as discharged fumes from industrial factories. Currently, there are areas of the world where the air quality has gotten so bad where people must wear masks to filter out the toxins while maintaining their regular daily lives.