What are the limits in his abilities? How tall can he get and how small can he get? Also is it true that he can generate pym particles from himself and change the sizes of other things other than himslef and what he is in contact with?

I think he can grow up to a 100 ft and lift about 50 tons in this size. He can shrink to a little smaller than the size of a common ant, and retain his normal strength whilst at this size. As he now generates Pym particles, he can shrink down any object he so chooses, so he can carry quite the surplus of weapons and equipment he deems necessary for the task at han. He can even carry shrunk down vehicles and entire labs on his pockets. He can also apply this ability to living beings, as he once reduced Tigra to being 15 centimeters tall. Theoretically he should also be able to increase the size of anyone, though people aren't used to size-growth will sometimes experiment physical discomfort or unconsciousness.