Im no expert but i dont think your dirty by smelling it. I could be wrong, but if you worried about it do what RIU said. Maybe get a home test kit and see if your clean.

If i was on probation i would try to stay as far away from weed as possible. Its not worth it, you dont want to go back on probation or back to jail. No rolling joints or nothing, stay away form it untill you done and then smoke a joint like the one in Killabuzz'z avatar.

Good luck.