Barking, blaring, and blasting assault the ears in world's noisiest nation

Japan is the noisiest country in the world. Its cities offer a constant aural barrage. There is the continuous rumble of heavy trucks on congested highways. Loudspeakers blare out commercials in local shopping areas or laud vote-seeking politicians. There are sound trucks for paper collectors or sweet-potato sellers.

And late at night, there is the symphony of road construction gangs or off-key barroom songsters.

''Noise pollution in Japan is the most serious in the world, and the noise is incessantly increasing,'' said a report by the government's Council for Science and Technology.

''If left as it is,'' it warned, ''there is a fear the hearing ability of Japanese will be jeopardized.''

In Tokyo's Nerima ward, this has already happened. Last November, the metropolitan government gathered 134 housewives, all but 40 of whom lived within a few yards of major highways. The women were placed in an echo-free room and subjected to varying sound levels. Those who lived close to the highway were significantly less sensitive to noise, while some long-term residents were actually hard of hearing.

Almost half the residents of major cities are subjected to high levels of noise on a continuous basis, a survey by the prime minister's office showed earlier this year.

The Environmental Agency says noise grievances accounted for one-third of the public environmental complaints it received last year.

When Japan was rapidly developing in the 1960s, ''it was thought the more noise the greater the economic success,'' says Yoshiko Sano, the feisty president of a small Noise Pollution Sufferers Association, which has been gaining new adherents as public attitudes change.

Japanese have certainly tended to be indifferent to the noise problem. Even now, surveys reveal that the majority of those acknowledging a noise problem feel there is nothing that can be done about it for a variety of reasons.

One factor is urban overcrowding. Hajime Goto, secretary-general of the Japan Noise Control Association, says, ''Today, more than three-quarters of the Japanese population occupy only 30 percent of the land. The dense concentration of population in cities is one of the main causes of excessive noise.''

Not everyone is willing to accept noise as an unavoidable adjunct of city living.

Two families in Tokyo's Suginami ward, for example, have filed a lawsuit against a neighboring family keeping nine dobermans. They are seeking heavy damages for disturbing the peace.

And there are several court cases under way - one of which is now before the Supreme Court - seeking to clamp down on or ban karaoke. These tape-deck and amplifier systems, which allow patrons of bars to sing their favorite melodies to musical accompaniment, are now enjoying a nationwide boom.

Okayama prefecture in western Japan last March became the first local government to establish an ordinance controlling noise by loudspeakers and other equipment. It has 13 articles aimed at ''maintaining calmness in communities,'' by establishing a noise maximum of 85 phons and virtually banning use of megaphones or other noisemaking instruments between 8 p.m. and 7 a.m.

The central government is also considering a report by a panel of pollution experts on establishing ''noise-free cities,'' although the emphasis is on cutting down traffic noise.

The panel is urging a major restructuring of urban areas to reduce vehicular traffic drastically, particularly by diverting trucks away from congested areas. Soundproof walls should be installed on all highways passing through residential areas, and where possible there should be ''noise cushions'' - like warehouses, office blocks, and even trees - intervening between the roads and private homes, it says.

The Tokyo metropolitan government is now working on a plan, which it hopes to launch next year, that would ''soundproof'' a 24-kilometer (15-mile) section of the capital's busiest road, Highway 7, which carries over 100,000 vehicles a day. Midnight noise readings in residential areas alongside the road regularly top 75 phons, compared with the national government's ceiling of 50 phons.