Vegetation color exposure differences at the community and individual levels: An explanatory framework based on the neighborhood effect averaging problem

Urban green spaces have multiple benefits, yet their distribution is often uneven. Studies on green inequality frequently adopt static exposure assessments, disregarding exposure during individual mobility, resulting in potential biases known as the neighborhood effect bias. Neighborhood effect averaging problem (NEAP) shows that exposure based on personal mobility tends to be average for all participants, compared to exposure based on residence. This study examines the NEAP in the context of green inequality by considering the ornamental value of green space, specifically vegetation color diversity. Considering that vegetation color can attract attention and has health benefits, we hypothesized that it is a key feature related to NEAP, as residents may compensate for poor residential environment by accessing better environmental quality during daily mobility. To investigate this, we compared vegetation color exposure at community and individual levels, assessing whether NEAP exists. Our findings suggest that while communities with high economic levels had significantly higher exposure to vegetation color diversity, the exposure at the individual level tended to be average. Moreover, NEAP appears to be more of an issue when considering vegetation color diversity compared to a measure of total green space such as green view index. We acknowledge that due to the responsiveness of survey, the survey sample includes a higher proportion of the well-educated and employed individuals with potentially higher mobility, which may influence the results. Overall, this study provides supporting evidence for NEAP in the context of vegetation color exposure, but not green view index, emphasizing the critical role of enhancing the ornamental value of green space and strengthening the quality of green space in improving green inequality.