Assessing Aircraft Noise Conditions Affecting Student Learning, Volume 1: Final Report (2014)

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CHAPTER 6. FUTURE RESEARCH RECOMMENDATIONS 6.1. Longitudinal Studies While previous studies have demonstrated effects of chronic aircraft noise exposure on children’s reading comprehension and memory, it must be acknowledged that the majority of the evidence comes from cross-sectional studies. The development of cognitive abilities such as reading are important not only in terms of educational achievement but also for subsequent life chances and adult health (Kuh and Ben-Shlomo, 2004). To understand the causal pathways between noise exposure and cognition, and design preventive interventions there is a need to study these associations longitudinally. Few longitudinal studies have examined the effects of persistent exposure throughout the child’s education: studies of the long-term consequences of noise exposure during school for later cognitive development and educational outcomes have not yet been conducted and remain of prime policy importance. While there is an ongoing follow-up of the UK RANCH cohort (Clark, Stansfeld and Head, 2009), research needs to address this question with some urgency. There is no longer a need for cross-sectional evidence and research should focus on longitudinal, prospective study designs. Longitudinal studies would also need to address the complexities of exposure assessment where children are placed in different classrooms for differing periods throughout their school life. 6.2. School Case Studies The effects of aircraft noise conditions on state standardized test scores for elementary school students identified in the current study should be supplemented by case study research aimed at answering the following questions: • What immediate, observable changes occur when a class is exposed to aircraft noise? How, if at all, do these changes vary based on the 1) nature of the teaching style, 2) lesson content, 3) disability status of the students, and 4) ESL status of the students? • How do students who are regularly exposed to aircraft noise at school differ from similar students who are not exposed to aircraft noise at school with respect to inhibitory factors including distraction, learned helplessness, memory difficulties, hearing and auditory processing difficulties, stress, health difficulties, noise annoyance, and absenteeism? • How do teachers who are regularly exposed to aircraft noise at school differ from teachers who are not exposed to aircraft noise at school with respect to inhibitory factors including stress, health difficulties, noise annoyance, absenteeism, and vocal strain? • To what extent, if any, is the effect of aircraft noise on students and teachers at school influenced by their exposure to noise at home? • According to students and teachers, how, if at all, does aircraft noise influence teaching and learning? Such case study research will inform future large-scale and longitudinal research to determine factors that mediate and moderate the effect of aircraft noise on student learning, a research priority that has been identified in previous literature (Boman and Enmarker, 2004; Hygge, 2003; Maxwell and Maxwell, 2000). It would also be useful to conduct future research at schools exposed to varying levels of aircraft noise in order to ascertain the varying influences of different noise levels, rather than using a dichotomous sample composed of noise-exposed and non-noise-exposed schools. 6-1

6.3. Classroom Acoustics Given the mounting evidence that aircraft noise is related to impairment of school performance, the question of what can be done to reduce noise induced learning impairments becomes salient. The literature suggests an increasingly important role of classroom acoustics on performance (Shield and Dockrell, 2008): In their study of noise exposure and national test scores for elementary school children, Shield and Dockrell (2008) successfully included internal acoustics in a sub-sample of 16 out of 142 schools: this illustrates the difficulties and potential lack of power of including classroom acoustics in such studies. Before-and–after studies could also be carried out at the individual level. Assessing exposure, cognitive performance and socioeconomic status at the individual level could more easily incorporate internal classroom acoustical information but such studies are likely to be on a smaller scale. Opportunities to conduct naturally occurring before-and-after experiments, where schools are already being insulated should be taken advantage of. Internal classroom noise has been demonstrated to be associated with performance and educational outcomes in recent years: further studies examining classroom acoustical factors such as reverberation and speech-to-noise ratios in relation to performance are required. 6.4. Combined Exposure To date, studies have yet to examine in detail how noise exposure interacts with other environmental stressors, such as air pollution (Clark and Stansfeld, 2007). Transportation systems (road traffic in particular) generate both noise and air pollution (e.g. particulate matter, nitrogen oxide, hydrocarbons etc) and there is some suggestion that air pollution may also influence children’s cognitive performance (Franco Suglia, Gryparis, Wright, et al, 2008). Studies have yet to address the effects of joint exposure to noise and air pollution. It is possible that the combined exposure to these transport related stressors could interact and increase their single effects. Air pollution could be a relevant factor for children’s learning in schools located near airports, as airport operations are usually associated with high levels of road traffic. Similarly, exposure to more than one noise source, such as aircraft noise and road traffic noise could have a greater effect children’s learning than either source alone, although the RANCH study found no effect of this type of combined exposure. 6.5. Thresholds for Effects Finally, while this study and the recent RANCH study has considerably advanced knowledge about exposure-effect relationships between noise and children’s cognition and health, further demonstration of exposure-effect relationships in different contexts and for different samples and vulnerable groups remains a research priority. Developing further knowledge about exposure- effect relationships will inform decisions concerning the design of physical, educational, and psychological interventions for children exposed to high levels of noise. Such relationships can be assessed using either individually collected cognitive performance data or via school-level test data. 6-2