Diseases in the respiratory system could start with an infection and entry of pollutants in the system, when we say infection this is the entry or the presence of microorganisms and the production of toxins that will then lead to disease production; the pollutants that enters the respiratory system may stick on the walls of the bronchial tree that also lead to breathing difficulty or the chemical pollutant may cause mutation and develop cancer. While in the circulatory system deposits of bad cholesterol from the food we eat may narrow the passage of the blood which leads to heart attack and stroke