Those spots really look like dust on your sensor. What do you think about this for a possible explanation: You were shooting in an area of high heat and humidity. You say that you had condensation in your lense when you brought it indoors or outdoors. I bet that the temperature change also caused condensation to occur on your sensor surface. If you had gotten dust particles on your sensor before the condensation occurred, you can bet that simply blowing air on the sensor afterwards would not remove them. They are stuck on after the condensation dried off.


As a suggestion, I think you want to use one of those sensor swabs with the cleaning fluid to clean off your sensor. Alternatively, if you do think that you had a lot of condensation exposure to your camera, may be contact Canon to see what they would charge to have them clean your sensor for you and to inspect the internals for any other impacts of excessive humidity/condensation.