Subject: Oxygen quality and content in the air during winter

My son asked me a question the other day I had no answer for: If we could not 
survive without plant life breathing out oxygen for us then why don't we have a 
harder time breathing in the fall and winter when all the leaves/plants are 
generally dead? You would think that would create a larger content of carbon 
dioxide in the air causing poorer air quality. Yet somehow, as a runner, I 
always seem to breathe better when outdoors in the winter months.

Re: Oxygen quality and content in the air during winter