Smoking

Smoking was very common in the black and white films from the 1930s and onwards. It was quite common to see the protagonist of the film to smoke regularly in the film. Smoking would add to the characters stylish and sophisticated personality. In an attempt to become more stylish and sophisticated, many people would smoke just like their on screen role models. The media use of smoking continued in the 1950s when large American Tobacco corporations began to sponsor Television shows and later commissioned adverts to promote their products. 

http://www.tobaccofree.org/films.htm