摘要: The report describes the recommended study design for an National Park Service(NPS) area visitor survey and a dose-response study to be conducted as part of the research for the NPS Aircraft Overflight Study. The NPS Aircraft Over... 展开 The report describes the recommended study design for an National Park Service(NPS) area visitor survey and a dose-response study to be conducted as part of the research for the NPS Aircraft Overflight Study. The NPS Aircraft Overflight Study is based upon the directives for research contained Public Law 100-91. That document states that the study should: (1) Determine the proper minimum altitude for aircraft flying over park units; (2) Identify any problems associated with aircraft overflights of park units; (3) Provide information regarding the types of overflights which may impact park units; (4) Distinguish between impacts caused by different types of aircraft activity; (5) Identify park system units and portions where the most serious impacts exist. 收起