Evaluation of PM2.5 Retention Capacity and Structural Optimization of Urban Park Green Spaces in Beijing

Dry deposition effect of urban green spaces on ambient particulate matter pollution in China

Particulate matter (PM) is a major source of urban air pollution that poses a serious threat to the environment and human health. This study quantified the dry deposition effect of PM2.5 and PM10 on vegetation using a mathematical model to overcome the limitations of traditional site-scale research. Additionally, multi-source satellite remote sensing products were combined to form a raster dataset to estimate the effect of dry deposition on PM2.5 and PM10 in China's urban green spaces from 2000 to 2020. The spatial and temporal changes in the long-term series were analyzed, and the influence of environmental factors on dry deposition was analyzed in combination with wavelet changes. The experimental results showed that: 1) from 2000 to 2020, the dry deposition effect of PM2.5 and PM10 on vegetation showed an initial increasing and then decreasing trend caused by the sudden drop in atmospheric pollutant particle concentration driven by local policies; 2) broad-leaved forests provided the main dry deposition effects in urban spaces, accounting for 89.22 %, indicating a need to increase the density of these forest types in urban development planning to improve air quality; and 3) PM2.5, PM10, and environmental impact factors have time-frequency scale coherences, and the coherence between PM2.5 reduction and these factors is more complex than that of PM10, with precipitation being the best variable to explain the change in PM2.5 and PM10. These findings are important for the prevention and control of urban air pollution, regional planning of green spaces, and sustainable development of cities.

Air Pollution (PM2.5) Negatively Affects Urban Livability in South Korea and China

This study investigated the effect of the concentration of ambient fine particulate matter (PM2.5), a transboundary air pollutant, on the livability of neighboring areas of China and South Korea with the aim of informing common policy development. Grey relational analysis (GRA) and panel regression analysis were performed to examine the effect of PM2.5 concentration on various livability indicators. The results revealed that urban living infrastructure was an indicator of effect in both South Korea and China. Based on the high correlation between urban living infrastructure and PM2.5 concentration, it can be seen that PM2.5 clearly affects livability, shown by panel regression analysis. Other key livability indicators were traffic safety, culture and leisure, and climate indicators. Spatial analysis of the livability index revealed that from 2015 to 2019, livability improved in both South Korea and China, but there was a clear difference in the spatial distribution in China. High-vulnerability areas showed potential risks that can reduce livability in the long run. In South Korea and China, areas surrounding large cities were found to be highly vulnerable. The findings of this research can guide the establishment of policies grading PM2.5 pollution at the regional or city macro-level.

From urban greenspace to health behaviors: An ecosystem services-mediated perspective

Urban greenspace can provide important health benefits for urban residents, but knowledge about the potential mechanisms remains unclear, and it is challenging in promoting health behaviors through design and management practices. This study proposed a hypothetical model that assumed ecosystem services as mediating factors between urban greenspace and health behaviors. An urban park in Beijing was selected as a case area to test the hypothesis and identify the ecosystem services-mediated pathways. Results based on spatial explicit mapping and multivariate statistical analysis confirmed the hypothesis and showed that urban greenspaces contribute to health behaviors in varying degrees through the delivery of health behaviors-related ecosystem services. The promotion effect was mainly mediated by cultural services, which is much more obvious than regulating services. We identified the importance of different properties of inner urban greenspace in promoting health behaviors through ecosystem services-mediated pathways. Green elements, especially tree canopy shaded ground, were found to contribute the most to health behaviors in the pathways, and slightly higher than facilities and grey elements. To promote health benefits, the design and arrangement of facilities and grey elements in urban greenspace is suggested to be cooperated with green elements for enhancing multiple ecosystem services. The findings will enhance the understanding of potential theoretical pathways from urban greenspace to health benefits, and support health promotion-oriented design and management practices.