BUENOS AIRES, Sept. 20 (Xinhua) -- Buenos Aires was ranked the fourth noisiest city in the world, with heavy traffic as one of the major factor to blame, a report by the municipal government said Sunday.

    "Traffic is one of the factors that most affect Buenos Aires," said the report issued by the Environment Protection Agency under the municipal government, which named Tokyo, Nagasaki and New Yorkas the top three noisiest cities.

    The three-year study, commissioned as part of the city's 2008-2012 Strategic Plan, first built a noise map of the city center and identified the boroughs of Barracas, Monserrat and Constitucion, and the Santa Fe and Pueyrredon Avenue as the noisiest areas.

    These areas regularly suffer between 65 and 80 decibels of noise. The World Health organization regards 70 as uncomfortable and 90 as harmful. Some 507,000 people live in the area surveyed.

    According to the department of electro acoustics of the University of Buenos Aires, areas which now regularly experience 70 decibels of noise had suffered only 50 or 60 decibels in the 1970s. As sound is measured logarithmically, a 3-decibel increase is a doubling of noise levels.

    Horacio Walter, director general of the Environment Protection Agency's technical evaluation department, said the city would soon be deploying a system to measure noise pollution in real time, enabling officials to swiftly locate and sanction noise polluters.

    A new city ordinance said that noise is not allowed to pass the level of 70 decibels in industrial areas and must be controlled under 80 decibels on busy city roads. Individuals risk fines of up to 50,000 pesos (13,000 U.S. dollars) for breaking these limits, and companies risk fines up to 100,000 pesos (26,000 dollars) and closures.

    So far, the city has handed down 928 fines this year under the new legislation.