Effects of Aircraft Noise: Research Update on Select Topics (2008)

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15 Some of the most promising research has been in the area of avi- ation noise effects on school children. Recent studies indicate a potential link between increased aviation noise and both reading comprehension and learning motivation, particularly for those students already scholastically challenged. The effect of aviation noise on children’s learning ability and retention of information in schools is of critical concern worldwide, with several new and potentially conclusive studies having been completed in the last few years. Most of the new research and related results have taken place either in Munich (using the old and new Munich airports before and after the closing of one and opening of the other) or the United States through FICAN. Most types of school effect studies utilize a binary definition; that is, describing two subject environments of noise exposure, a high-noise setting and a low-noise setting, which make it difficult to define a dose- response curve. However, it is usually clear that noise levels above a certain Leq affect a child’s learning experiences. In 1995 and again in 1998, Evans et al., studying school children living in the vicinity of the Munich airport and a in quiet suburban area, demonstrated that children within high-noise areas showed evidence of poor persistence on challenging tasks, and reported considerable annoyance with community noise levels, adjusted for individual differences in rating criteria for annoyance judgments (Evans et al. 1995, 1998). Other studies by Hygge et al. (2002) examined aviation noise effects on children in the area around the old and new Munich airports. They reported that three data waves were collected, pre- and post-switching of the airports. Long- term memory and reading were impaired in the noise group at the new airport, although there was improvement in the formerly noise-exposed group at the old airport. Short-term memory also improved in the latter group after the airport was closed. Speech perception was impaired in the newly noise-exposed group. Other interesting and unexpected differences in the effects of aviation noise on classroom learning experiences come from Hygge’s study where children aged 12 to 14 years were tested for recall and recognition of a text exactly one week later (Hygge 2003). Overall, there was a strong noise effect on recall, and a smaller but significant effect on recognition. Using a sound source located in the classroom, the single- source studies—aircraft and road traffic—impaired recall at both noise levels, yet train noise and verbal noise did not affect recognition or recall. Given that road noise and verbal noise were relatively constant sources and the aircraft and train noise were event-type sources, these observed differ- ences were not expected. In 2000, FICAN published a position paper regarding effects of aircraft noise on classroom learning. It summa- rized research on its effects, and indicated that aircraft noise can interfere with learning in the areas of reading, moti- vation, language, speech acquisition, and memory. The strongest findings are in the area of reading, where more than 20 studies have shown that children in noise-impact zones are negatively affected by aircraft. Research has confirmed conclusions from studies completed in the 1970s that show a decline in reading when outdoor noise levels equal or exceed Leq of 65 dBA. Recently released and not yet fully reviewed is FICAN’s initial study involving 35 public schools in Texas and Illinois near three airports (“Findings of the FICAN Pilot Study . . .” 2007). Results of the study indicate that the Student failure rate may be due to impaired learning in the class- room, perhaps caused in part by noise stress. To the extent that noise stress contributes to student failure, then failing students are the ones most likely to benefit from noise reduction. In contrast, top-score students are less likely to benefit. Such a rationale is consistent with the results of this study. This study’s analysis is not yet fully reviewed. Regarding indoor classroom acoustical performance criteria, two main works stand out that additionally comple- ment each other. The Acoustical Society of America provides performance criteria, design requirements, and design guide- lines for new school classrooms and other learning spaces (“Acoustical Performance Criteria . . .” 2002). These criteria are keyed to the acoustical qualities needed to achieve a high degree of speech intelligibility in learning spaces, and the standard is a very good guideline for best practices in class- room acoustical design. The second publication is a very technical comparison of speech intelligibility metrics in the classroom based on various background noise (Bistafa and Bradley 2000). The study, consistent with the ANSI standard recommendation for steady-state noise, recommends ideal and acceptable background noise levels of classrooms, but does not address intermittent noise such as noise from outdoor transportation. CHAPTER SIX EFFECTS OF AVIATION NOISE ON SCHOOLS