Black specks coming from wood stove chimney
We heat our 5 year old bungalow with an air tight wood stove, with electric baseboard as backup. The stove has been in almost constant use since November as it is very cold where we live. We burn hardwood exclusively except for softwood kindling to start the fire should it go out. The pipe from the stove is 6" double wall to the ceiling for a total run of 6 ft. The chimney is a SS insulated at 7" diameter through the attic and extends about 10 ft above the roof line to clear the ridge. It has a special cap that prevents downdraught. The chimney is cleaned once per year in the fall before the heating season. We were away for 2 days and when we arrived home we immediately started a fire. The next day when we went outside, we noticed the snow in the front yard was littered with many small black specks that were not there when we came home. This had to have come from the wood stove when we first started it. Is this a sign of a problem? Should I be concerned? Thanks for all responses.