Theoretically, changing lenses can expose the sensor to more dust in a "mirrorless" camera design, compared to DSLRs that have both a mirror and a closed shutter protecting the sensor. Mirrorless cameras have dust-removal systems which attempt to minimize the impact of this problem.
Other types of dust reduction systems:
Piezo crystal ultrasonic vibration of filter
This system vibrates the thin filter surface that covers the image sensor many tens of thousands of times per second (35,000 to 50,000 hertz) to remove particles from the filter.
Sensor shifting
This type of systems moves the actual sensor to help reduce dust. It vibrates the actual sensor at around 100 Hz. The amount of movement or sensor travel is larger that the higher frequency filter vibrating types.A crude analogy to compare it to the piezo crystal filter method is something like hitting or banging the sensor to displace the contaminant, whereas the piezo vibrates a filter to make the particles fall off.
