View on outdoor vegetation reduces noise annoyance for dwellers near busy roads

The effect of outdoor vegetation, as seen from the living room's window facing an inner-city ring road, on the self-reported noise annoyance, was studied. Face-to-face surveys were taken at 105 participants at their homes in the city of Ghent (Belgium). The living room window, facing the road, was in all cases highly exposed to road traffic noise and characterized by Lden levels between 65 and 80 dBA, as taken from the official European Environmental Noise Directive's city road traffic noise map. All houses were selected to have a pronounced front-back level difference to rule out this effect. The self-reported extent to which vegetation is visible through the living room window was shown to be a strong and statistically significant predictor of the self-reported noise annoyance. The complete absence of view on vegetation results in a 34% chance of being at least moderately annoyed by noise, while this chance reduced to 8% for respondents answering to have a very pronounced vegetation view, notwithstanding median Lden levels of 73 dBA at the street-facing facade of the dwelling. Real vision on outdoor vegetation was shown to be essential - living room (indoor) plants and the mere presence of vegetation in the neighborhood is insufficient. Road traffic noise facade insulation, measured in-situ at each dwelling, could not be linked to the self-reported noise annoyance.