Hello, when you buy firewood, make sure that you are buying good seasoned firewood. Ensure that it was cut and split at least a year ago and then stored so that air and sun can dry it out. A good sign would be to look out for the cracks in the end grain of the logs, as it's potentially dangerous. Burning wet wood produces more smoke than dry wood, which releases more pollutants and small particles into the air. Burning wet wood can also cause creosote buildup in your chimney.