Aircraft noise around Kadena and Futenma: how to read the official data

What Lden means

The report's main figure is Lden, in decibels: a day's aircraft noise, with extra weight on evening and night. Higher means louder.

Japan's environmental standard is 57 dB for areas used mainly for housing (Type I) and 62 dB for other areas where normal living needs protecting (Type II).

The same base, very different numbers

Around Kadena, 11 of the 18 stations that could be evaluated exceeded their standard. Around Futenma, 3 of 12 did. Compare stations near the address you are considering, and check the standard for that station in the report.

Look beyond the average

An average hides what you would actually notice. The report gives these too.

• How often: The busiest stations averaged 67.0 events a day at Yara A and 58.8 at Aragusuku.
• How loud at peak: The highest single readings were 118.8 dB at Sunabe and 123.3 dB at Kamiojana.
• At night: Between 10 pm and 6 am, Yara A averaged 244.0 events a month and Masaki 75.9. A 1996 Japan-US agreement restricts flights in those hours, but events are still recorded.

What the data cannot tell you

Stations measure fixed points, not your street. Figures change from year to year and with flight activity. They do not tell you how you will feel about the noise.

So use them to decide where to look closer, then go in person. Visit at the hours that matter to you, including early morning and at night, and on more than one day.