No one suggested that pixel size and particle size had to be related to see. Higher density sensors have been more sensitive to dust however and there are factors that separate the older sensors from the new types that are reportedly faster to accumulate dust. A higher pixel density sensor has a lot of differences, from the current density of the sen-cells, the location of the active elements in each pixel(the newer high density sensors are back illuminated and the older low QE sensors were front illuminated). Proven time and again? Where? I have seen no variable-controlled tests that prove anything of the sort. The people speculating on scratches or chips etc are also the ones who seem to not want to test carefully or to bother with maintaining their own gear, just exchange when one gets dirty. I am waiting for additional people who have been attentive to cleaning as needed, to see the rate of recurrence. Those who have kept records are contradicting the "defective camera" lobby by reporting that the dust goes away after a modest number of cleanings. If you wish not to clean or maintain your gear, there are many options in pursuing your photographic hobby but getting most of out the newer higher performance cameras is not one of them.
I am still at a loss as to why so many people are so adamant about not cleaning their sensors. They have no problem cleaning their windshields, or washing and waxing their cars so what is the difference other than the sensor is harder material and more scratch resistant, plus much cheaper to repair or replace than a scratched paint job on the car. I bet some of them also have contact lenses and clean and install them on surfaces much less hardy than OLPF's over sensors. Could it be that these newer cameras are just not for them? Stan St Petersburg Russia