The seal between lenses and the camera are not exactly air tight. Zoom lenses must allow air to move so that the elements can move.
Some dust on your image sensor is inevitable.
I noticed that the two posted image were shot at f/22. Small apertures make dust spots more visible in image. Try shooting at f/11 or f/16. It is likely that those apertures are small enough to provide the depth of field that you need especially with a wide angle shot.
Shooting at very small apertures not only makes sensor dust more visible but it can cause the images to be softer then they should be due to diffraction.