That's not a vent pipe, but there are quite a few around the city, Their main job is venting the storm drains and sewers, not to let the smell out but to allow air to escape when sudden high demand fills the pipes and the risk of air locks could hinder the water running away smoothly. Sewer gas is lighter than air and escapes upward, not where anyone can smell it. Some places in the country used to have gas lamps burning 24/7 to dispose of it, as it is flammable.