Sunset Reveals Dust on My Image Sensor

I've had these two trouble spots for about 6 months now, probably dating back to when I changed lenses in the middle of a windy field. I can't tell if they are on the lens or the image sensor. Is there a way to tell just by looking at the image? I bought a rubber blower thing but I can't seem to get rid of these little pieces of debris!

Update: Success!!!! Duh