"The lungs are constantly throwing off impurities, and they need to be constantly supplied with fresh air. Impure air does not afford the necessary supply of oxygen, and the blood passes to the brain and other organs without being vitalized. Hence the necessity of thorough ventilation. To live in close, ill-ventilated rooms, where the air is dead and vitiated, weakens the entire system. It becomes peculiarly sensitive to the influence of cold, and a slight exposure induces disease. It is close confinement indoors that makes many women pale and feeble. They breathe the same air over and over until it becomes laden with poisonous matter thrown off through the lungs and pores, and impurities are thus conveyed back to the blood. MH 274.1"
"What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own?"
The EGW passage directly applies the principle of the body being a temple by emphasizing the need to care for it through proper ventilation and avoiding impurities. It's a practical application of the biblical concept.