Surgical masks are also used by the general public in heavily populated countries in East Asia to reduce the chance of spreading airborne diseases. In Japan, it is common to wear a face mask whilst ill to avoid infecting others in public settings.[1] Surgical masks were widely used in China, Hong Kong, Vietnam, and Toronto, Canada during outbreaks of the SARS virus, during the 2007 bird flu pandemic in Japan, and in the United States and Mexico City during the 2009 H1N1 flu outbreak, also known as the swine flu. It is also worn by people in dusty environments such as sanitation workers.