I would think one of the biggest things for dogs in the city is noise. When I first got Kobi I made it a point to walk him on the major roads with buses and large trucks. Horns blowing, air breaks, sirens and general load traffic noise can spook a dog. Depending on where Nemo will be going other things to consider are riding in elevators, buses and subways, as well as on escalators or through revolving doors.