Ah christ. I realized earlier today that I screwed up the formula. It shouldn't follow the inverse square law. Since repulsors need another mass to bounce off of to work, it works more like radar - the particles or field or whatever the repulsors emit needs to bounce back and forth between the objects to work - hence how things more around disproportionate to the power applied. So it should be to the 4th power, not 2nd. That debris isn't even going to hit the upper atmosphere, it will stop over a planetary diameter out.
That said, the low interaction between repulsors and low density objects (eg grass, air, etc) means that the fine debris may not be deflected, depending on the exact properties of it and the repulsor field.
If I were writing, I'd figure that the FME will need outside help to prevent getting hit by debris later on, and to mitigate the damage the fine debris may do (probably inducing a new ice age or something), but initial extinction is precluded.
The Endor Holocaust
Moderator: Vympel