In our house there were 2 fireplaces. One upstairs, one down. The upstairs fireplace was well kept and was used to warm the main level of our house. In the winter, this was a great source of warmth in our house. However, to keep the fire stoked with wood, someone would have to tiptoe out the back sliding glass door periodically to get more wood. Upon doing so, a blast of cold air would rush into the main room and chill us all for a few seconds until the door was again slid shut.
The downstairs fireplace was a whole different animal. For some reason, the cold air would be pushed down the chimney. I'm sure there is a scientific reason for the down draft that made lighting a fire down there a difficult task. I remember several times trying to light newspaper down there only to receive a face full of smoke in return. The first blast of smoke was from forgetting to open the flue. The second blast of smoke was from the down draft of cold air. The instruction and scientific explanation was given that enough heat had to be applied at the beginning to get the air to start flowing back up the chimney. Once this delicate balance of hot and cold was overcome, the smoke would cease to fill the room. After several minutes of gray plums of smoke layering the downstairs family room, the miracle of the chimney would occur and the room would begin to filter up the brick column.
I am sure that as I get older, I will find that I have a layer of soot embedded deep in my lungs that will eventually kill me. Yes, I am sure I have a very minor case of Black Lung right now. I always new I would die of cancer.