I can associate different smells with different events times of the year etc. For us in the northern hemisphere it is fall and the weather is getting colder. Tonight the house was 55'f and I had a little chill, time to check out the furnace. I have lived in this house for 21 years and each time the furnace is fired after sitting idle for the summer there is the smell of burning the dust and getting rid of the humidity in the ductwork. It is not overly pleasant. One year I did think about doing it when it was warmer and the windows were open. :-] In its own way it is comforting though. Another year has passed, things are going well, and although colder weather is on its way we will be warm inside our nest.

Tim