Noise effects in schools
Some of the external costs of aircraft noise, have been identified in the development of lawsuits brought by city school authorities against city airport authorities for damages to the educational process in schools who were impacted by aircraft noise.
An example of the effects of aircraft noise (having peak levels of 87 dB outdoors and Ldn levels of 70 dB) on various school, activities were documented by the teachers in some schools in San Diego, California. Comparable data was obtained from teachers in London (Crook and Langdon, 1974) and Hong Kong (Ko, 1979).
It is obvious that some of the activity interferences from aircraft noise are to be expected as a result of masking effects of noise on speech communications.
Other studies, unpublished, conducted by the High Line School District (near Seattle, Washington) revealed somewhat longer-duration effects from aircraft noise in schoolrooms.
Studies in High Line School
In a High line School District (1976) study (Maser et al., 1978) an analysis of the school achievement test scores over school grades 3-7 and 5-10 revealed that high-academic-aptitude students in schools exposed to aircraft noise did as well as those in quiet schools.
Achievement was measured by standardized tests administered to the students each school year. However, middle and, especially, low-academic-aptitude students in the noisy schools showed progressive deterioration in school achievement tests with continued school attendance as compared with the achievement of cohorts of equal aptitude in quiet schools.
The differences between the test scores of students in the lower third of academic aptitude, in the "noisy" (noise-exposed) schools versus the quiet schools, were statistically significant for the seventh and tenth grades. The socioeconomic characteristics, according to city and school officials, of the students from the noisy and quiet schools were similar.
The most significant difference between the schools was the fact that the noisy schools were exposed 50 times or so on a near-daily basis to aircraft noise reaching peak levels of about 90 dB (Ld —70 dB). It should be noted that in the San Diego and Seattle studies just discussed, the buildings were typical masonry school structures, but they were not air-conditioned or specially sound proofed.
The related lawsuits were settled by the aviation interests paying for the costs of sound proofing certain school structures and/or building new structures in quieter areas.
Cohen et al. (1981) also found a generally adverse effect of intense aircraft noise (peak levels as high as 95 dB outdoors) on reading and math achievement in grades 3 and 4. Additional evidence of a cumulative adverse effect of freeway noise can be found in a study by Lukas et al. (1981). Some apparent degradation in reading achievement occurred with increased classroom noise in third-graders. This effect was accelerated by the sixth grade. Bronzaft and McCarthy (1975) and Bronzaft (1980) reported that the noise from elevated trains going by grade schools also had more pronounced adverse effects on the reading achievement scores of sixth-graders than on third-graders.
Cohen et al., (1981) found that the amount of aircraft noise around the residences of the children, as well as that at their schools, contributed to a lowering of school achievement scores. This is consistent with an earlier study by Cohen et al. (1973) of the effects of freeway noise around high-rise apartment buildings on the reading ability of children measured in the school.