According to the California Air Resources Board the types of air pollutants emitted when using a gasoline-powered leaf blower for half an hour are equivalent to those emitted from 440 miles of automobile travel at 30mph average speed.
Add that to what is actually being blown and you have a nightmare. You have diseased particles and fecal matter from bugs, dried diesel and gasoline, oil, you name it. This should not be allowed in any building.