Complaints about the roar of aircraft taking off at Yokota Air Base in western Tokyo have soared over the past year or so, with one municipality reporting in excess of 10,000 instances for the first time in 10 years.
"We suspect the noise pollution reflects a general increase in the number of flights at the base," said an official with the city government of Fussa. "However, no explanation has been offered for the increase."
The U.S. Air Force base occupies an extended area in Fussa and five municipalities with runways extending north to south.
In fiscal 2013, Fussa's Kumagawa district, located on the southern tip of the base's main runway, recorded 11,137 occasions in which the roar of aircraft topped 70 decibels for more than three seconds.
Seventy decibels is the government standard to determine noise pollution, and is equivalent to the sounds of a typical busy city street.
It was the first time for the figure in the district to exceed 10,000 since fiscal 2003, jumping from 8,076 instances recorded in fiscal 2012.
Recorded cases of noise pollution in the district is on the rise this fiscal year as well.
Between April and July, 3,961 cases were recorded, 678 more than in the same period in fiscal 2013. On average, the figures have increased by 170 cases per month.
Mizuho, a town on the north side of the base, faces the same problem.
The town's Hakonegasaki district recorded 9,591 cases in which aircraft noise exceeded 70 decibels for more than three seconds in fiscal 2013, a jump from 8,520 cases the previous fiscal year.
Akishima, a city located just south of the base, is also experiencing a rise in noise pollution.
"We believe there was more aircraft noise in fiscal 2013 compared with the previous fiscal year," an official with the city government said. "We are receiving more questions and complaints from residents with regard to this issue."
When asked for comment, officials at Yokota Air Base said they have not changed any of their programs and that all their flights are conducted on the basis of regulations and agreements signed between the governments of the United States and Japan.
However, they promised to take note of local concerns and make an effort to conduct operations and training programs only when necessary.