In Traditional Oriental Medicine the Lungs govern Qi and respiration. They’re responsible for inhaling Qi from the atmosphere, combining it with the Qi received from food and spreading the resultant useable Qi throughout the entire body. The Lungs are called the tender organ because they are the most external organs and they connect the body to the outside world. The Lungs are easily attacked by external pathogenic factors, in this case smoky, ashy, hot air. When the air we’re taking in is poor quality, we tire easily. Of course, when we’re breathing fine air and eating garbage we get tired easily, but that’s another discussion.
The books that the world calls immoral are the books that show the world its own shame.