In this study, indicators are proposed to characterize the intrinsic environmental properties and external value of urban parks. The intrinsic properties involve both acoustic factors and non-acoustic factors, such as visual aspects and size. To assess external value, the restoration level is defined, which measures the nearby presence of a quiet, 'green' area at residential areas outside parks. The restoration levels of green areas are based on intrinsic properties and the distances of each dwelling to urban park areas. The overall environmental value of a park, the group restoration level, is defined as a logarithmic summation of the restoration levels over its surrounding residential areas. Restoration levels were determined for sixteen public parks in the city of Rotterdam and compared with survey data from questionnaires. Results show that the investigated parks display a large variation in the group restoration level levels, mainly due to differences in size and average noise levels. To validate the proposed method, survey data from questionnaires are investigated as to correlation with restoration levels.
