A person on a dirt bike is in the air.
The person is riding a bike outside.
A dirt bike is a specific type of bike typically only ridden outdoors, therefore it is most likely being ridden outdoors.
exists p1 x1 x2 x3 x4.(n_air(x4) & in(x1,x4) & on(x1,x2) & n_bike(x2) & of(x2,x3) & n_dirt(x3) & n_person(x1))
exists e1 x1 x2 x3.(n_person(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_outside(x2) & of(x2,x3) & n_bike(x3))