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Aircraft
Noise and Kids Health, The LAX Study
USA report.
Another Scientific Study Overlooked in the County of Orange Environmental
Impact Report for establishment of a commercial airport at El Toro.
This summary was prepared from the original report by a scientist member of
the El Toro Airport Info Site Team.
For additional information, visit the web
site on the Internet at http://www.eltoroairport.org and e-mail inquiries to the
site.
Physiological, Motivational, and Cognitive Effects of Aircraft Noise on
Children: Moving From the Laboratory to the Field. American Psychologist, Vol.
35, March 1980, pp. 231-243 Sheldon Cohen, Gary W. Evans*, David S. Krantz, and
Daniel Stokols*
*University of California, Irvine, CA.
Noise pollution has been primarily linked to a loss of hearing.
Recent
studies, however, have suggested a link between noise and physiological
processes associated with stress.
These processes, including elevated blood
pressure and levels of stress hormones, are considered a health hazard.
Further,
it was suggested that children, the sick, and the elderly are the most
susceptible to noise impact, because they lack the ability to develop a coping mechanism.
An inability to cope with stress can lead to increased
feelings of helplessness that, by themselves, can lead to illness.
The authors
decided to test this hypothesis by examining the effects of aircraft noise on
school children in Los Angeles.
Children were selected from the four noisiest elementary schools in the air
corridor of Los Angeles International Airport.
Peak noise levels reached 95
decibels (dBA), on the A scale, with one flight every 2.5 minutes.
As a control
group, children were also selected from three schools in quiet neighborhoods
with matching socioeconomic status.
A total of 262 children, from third and
fourth grades, participated in task performance, on two consecutive days for 45 minutes.
Children with existing hearing problems were
excluded from the study.
Noise levels were measured for one hour in the two neighborhoods.
Mean peaks
for noisy schools were 74 dBA, as compared to 56 dBA in the quiet ones.
This
difference is significant because an increase of 10 dBA is considered to be
twice the level of noise.
Perception. Both parents and children from the high noise schools perceived
higher levels of noise at home, compared to their counterparts from the quiet
schools.
Further, the level of noise reported by the parents of the noise-school
group increased with the length of living at the same residence.
Physiology. Blood pressures were monitored once per day and averaged. The
authors noted a significant change in blood pressure between the two groups,
with children from the noisy schools exhibited higher blood pressure than the
children from the quiet schools.
Motivation. It has been suggested that exposure to high intensity noise can
induce feeling of helplessness, which often occur when an individual cannot
control or change a stressful event. This feeling, in turn, can decrease
motivation to initiate new tasks and to lack of persistence giving-up.
Children
were administered a success-failure test where both a response to failure and
giving-up are considered as indication of helplessness.
Each child was required to solve a puzzle. Half were given an insoluble
(failure) puzzle, while the rest received a soluble (success) one.
After the
allotted time passed, all the children were required to solve a second, soluble
puzzle, of moderate difficulty.
The percentage of failure to solve either
puzzle, as well as giving-up, was higher among the children from the noisy
schools, compared to their counterparts from the quiet ones
Further, the
differences appeared to increase with the duration of school enrollment, for
children with longer exposure to aircraft noise.
Cognitive. It has been suggested that children reared in noisy environments
become inattentive to sound, by tuning it out.
When this inattention includes
speech-relevant sound, it may lead to reading problems.
It was hypothesized,
therefore, that children using such a selective inattention strategy might be
less affected by noise distraction.
To test this hypothesis, children were given
a six-grade level essay, where, within a time limit, they were required to cross
out all the e's on the pages.
One test was performed while a recorded story, at
a moderate voice, was playing.
The second test, using a different essay, was
conducted under background noise conditions to provide a baseline.
A significant
difference in the number of e's found was observed between the noise-school and
the quiet-school groups, and it was associated with the length of enrollment in
school.
During the first two years of enrollment, the children from the noisy schools
did better than their quiet-school counterparts.
After four years of exposure to
noise, however, their performances deteriorated.
The authors concluded that this finding suggests that as the length of noise exposure increases, children
are more disturbed by auditory distractions.
Further, the authors suggested
that, at first, the children attempted to cope with noise by tuning it out.
Later, however, they gave up when they realized that this strategy did not work,
behavior consistent with helplessness data.
Last, the authors looked at 20 children from the quietest homes who were part
of the noise-school group.
This sub-group was more susceptible to the effects of
noise, as was determined by their lower performance in several of the tests and
their elevated blood pressure.
Thus, living in a quiet neighborhood did not
lessen the impact of exposure to noise while at school.
This study, concluded the authors, added weight to a possible impact of
aircraft noise on psychological adjustment and on non-auditory aspects of health
on children.
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