(4-3) Aircraft noise around an
(1) Reaction at the exposure of the high noise level
of an air craft
We did a noise survey at a primary school
near the Osaka International Airport in 1974. We observed children in the play
ground from the roof of a school building, they kept playing without any
surprise at the exposure of a high aircraft noise of over 100 dB (A).
We set a frame camera on the roof for
monitoring them with noise measurement simultaneously. They were playing dodge
ball games. We took them in the area A or B in the playground from the school
building roof. Their locations are shown in Fig.1 and 2.
We arranged white lines to get the
coordinate of the ground while they were not there.
Fig. 1 Play ground and school buildings
showing the camera location and the areas monitored
2 Elevation of the school building to have a frame camera on the roof
We superposed them and found the moved
distances of particular students from two successive frames. From the moved
distance onefs velocity and acceleration were calculated. They were compared
with the air craft noise simultaneously measured. It is shown in Fig.3.
Fig.3 Moved distance, velocity and acceleration
of particular students in the playground at the exposure of high aircraft noise
The moved distance and velocity did not
change much with the noise, but the acceleration seems to be decreased
When any huge energy is given,
one hears large impact sound. It seems that this correlation is imprinted in
Unfortunately, we could not have
time to give them a similar large air craft noise from a different direction on
(2) Social survey on aircraft noise near the Osaka
This is a
part of the report about the aircraft noise survey around Itami City and adjacent
cities near the Osaka International Airport.
for winter time were distributed to 1219 people from Nov. 28, 1972 to Jan. 16,
1973. Invalid answers were 10. For summer they were given from Aug.4th,
1973 to Aug. 31st, 1973 at Itami City and its near areas. They were
2,333 and invalid answers were 6.
aircraft noise survey was done in 11 cities simultaneously from Nov. 1973 to
Jan. 1974. The noise level contours for peak levels in dB(A) with 5 dB(A)
interval were obtained as shown in Fig.1.
Fig-1 Contour lines of peak level
dB(A) with 5dB(A) interval
The contours for WECPNL with the
conventional method are shown in Fig.2. They have 5 WECPNL intervals too.
Fig-2 Contour lines of WECPNL
with 5dB interval
With the answers in summer and winter in
Itami city, scores were obtained for 13 factors using the theory of quantification
II. The outsider had four classes, gnot annoyed and a little annoyedh, gannoyedh,
gvery annoyedh and gextremely annoyedh.
The partial correlation
coefficients, which show how strongly each factor is related to the outsider,
are shown in Fig.3 which was obtained from the above quantification. The
outline of the theory of quantification II by Hayashi is given in Chapter V of
my home page www.ecohouse.co.nz.
The difference of seasons, summer
or winter, has the second contribution after the factor of peak level. In
summer, living condition is different from winter. They tend to open windows
and loose sound insulation. Another possibility is that flight courses are
different and areas of higher noise level were increased.
Fig.-3 Contribution of each factor (partial
correlation coefficient) to annoyance having the factor summer or winter.
Three factors, peak level in
dB(A), duration time and the number of flight, were used as factors to affect
annoyance, the peak level was dominantly large compared with other two.
The number of flight has a small
contribution, because it does not have much difference at the surveyed area.
To eliminate any biased answers
to the question of aircraft noise, it was given after prior questions for a
living environment. This way of questioning at a social survey is called the
OECD method. Questionnaires were given directly on aircraft noise in parallel.
The former is called gindirecth and the latter is called gdirecth. They were
chosen as categories for a factor.
Which has more contribution to the
annoyance of an aircraft noise a peak level (in Fig.1) or a WECPNL (in Fig.2)
was examined having them in a factor?
17 factors were selected for the
quantification and the partial correlation coefficients were obtained in Fig4.
factors which affect to the annoyance of aircraft noises, the noise level of
averaged peak level dB(A) affects dominantly, namely it has the most partial
contribution of the factor gdirecth of gindirecth was not large. It was
resulted because all the area was exposed to high aircraft noise. However,
their scores not given here showed
Contribution of each factor (partial correlation coefficient) to annoyance with
a factor direct or indirect questionnaire
survey answered more annoyed.
On the partial correlation
coefficient, peak level has more contribution than WECPNL.
In such a noise environment, duration time
and the number of flight do not affect much and the peak level is enough to
express the noise environment.
The experience of noise environment
at the former resident has the second largest 0.158 to the aircraft noise
rating. It means the factor should be counted at any other noise survey.
The flight course is large with
0.128. It must be caused by the diffraction of surrounding houses.
As peak level dB(A) affects dominantly
to the annoyance of aircraft noise, the next discussions are done with it.
Distribution of responses to an aircraft noise
Each block was classified with 5 dB(A) step
for the average of peak level dB(A). Annoyance and disturbances of speech
inside and outside were converted to the distance scale for their categories.
Each answer was estimated on the scale and it was averaged in each block in
Each of the three items is shown
in the next three figures. There the correlation coefficient is given. Not only
for annoyance but disturbances of speech, the response shows different attitude
at the level over 95 dB(A). The 95% confidence interval is given in Fig.6. It
has a wide range
Fig. 5 Distribution
of annoyed areas around the Osaka International Airport
and covers adjoining categories. It shows
that the response to an aircraft noise has wide
Fig. 6 Relationship of peak
levels vs noisiness
Fig. 7 Relationship peak levels
vs speech disturbance inside
Fig. 8 Relationship of peak levels vs speech disturbance outside
Answers in summer and winter showed significant
difference and they feel more annoyed in summer. They tend to open windows and
loose sound insulation. Another reason is different flight courses and areas of
higher noise level were increased in summer.
It was shown that a flight course
related to adjoining houses affects as well. It was caused by the diffraction
and might be affected psychologically if it is visible or not.
It was shown that noise level
with peak level dB(A) or conventionally measured WECPNL was dominant to decide
the annoyance in this region. However, their partial correlation coefficients
were unexpectedly not that large with 0.459 and 0.414. It was caused by the
distributions of noise level measurements and individual responses.
The difference of partial
correlation coefficients between peak level dB(A) and conventional WECPNL was
When we get responses on a noise environment
in living environments we have to consider their history of noise environments,
other noise sources, diffraction and sound insulation, seasons etc.
Because of the large distribution
of responses more objective scale such as the Guttmann scale or a pair
comparison might be needed to consider to be used. The measurement of noise
levels should not be done on a few days but would need, for instance, a year or
four seasons. When noise level distribution in a wide area is measured, enough
number of measuring points is needed.