With the progress of industrial development and urbanization, complaints about environment pollution such as air pollution, noise and offensive odors increased sharply in the 1970s in Japan. To take measures against offensive odors, the “Offensive Odor Control Law” was enacted in 1972 and regulates offensive odors emitted from business activities. It could be progressive as few countries have laws applying only to offensive odors. Since then, various efforts toward improvement under this law resulted in a decreasing number of complaints. However, the number increased little by little after 1990. One of the causes of this increase is that people have become sensitized to odors generated in daily life. Complaints about livestock farming and manufacturing plants have been decreasing, while those about service industries and private households have been increasing.