Effects of overflights on the national park experience

Visitors to parks and protected areas expect tranquil surroundings, and the ability to hear the sounds of nature. With the spread of anthropogenic noise into natural areas, experiencing quiet and the natural soundscape has become more difficult. Aircraft overflights offer one such example. Previous research shows we can detect low levels of noise in urban and natural settings, that noise pollution detracts from the enjoyment of the visitor experience, and that we place a high value on naturally quiet, pristine settings. In the current study, a laboratory simulation was employed to differentiate between three types of aircraft noise common to national parks. Two-hundred sixty-eight participants rated 40 natural landscapes synchronized with natural sounds or aircraft overflight noise in a between-subjects design. Overflight noise was presented at a maximum of 50 dB(A) with a 25 percent audibility rate. Participants rated each scene on several psychological dimensions related to a national park experience: annoyance, scenic beauty, tranquility, solitude, naturalness, and overall preference. Results revealed statistical differences between the three aircraft noise conditions and natural sounds on annoyance, solitude, and tranquility. Helicopter noise was perceived as the most disruptive to the national park experience, followed closely by propeller plane noise, with jet airplanes being the least negative of the three noise conditions, when noise was present. Results show the importance of natural sounds, and the negative consequences associated with exposure to aircraft noise in a national park context.