The airport authority estimates that about 30,000 residents live in the neighborhoods closest to the airport and its flight paths, where the average of day and night aircraft noise is more than 65 decibels. A decibel is a unit of noise; city traffic is about 75 decibels. The Post survey area is larger, including areas where the average aircraft noise level is above 55 decibels.

When asked, "When was the last time you recall being bothered by the noise from planes from National Airport?" 59 percent of the smaller group of noise zone residents said they had been annoyed that day or within the past day. Another 28 percent said they had been bothered within the past week.

The residents who are bothered are not quiet about it, as airport managers and local officials well know. The poll found that almost half, 49 percent, of the annoyed noise zone residents said they had complained about National airplane noise to a friend or neighbor within the past year.