A growing body of empirical evidence is revealing the value of nature experience for mental health. With rapid urbanization and declines in human contact with nature globally, crucial decisions must be made about how to preserve and enhance opportunities for nature experience. Here, we first provide points of consensus across the natural, social, and health sciences on the impacts of nature experience on cognitive functioning, emotional well-being, and other dimensions of mental health. We then show how ecosystem service assessments can be expanded to include mental health, and provide a heuristic, conceptual model for doing so.

Nature and mental health: An ecosystem service perspective.

Social cohesion involves the interpersonal dynamics and sense of connection among people. Increased social cohesion can be associated with various physical and psychological health benefits. The presence of urban green spaces can encourage positive social interactions that cultivate social cohesion in ways that enhance health and well-being. Urban green spaces have also been linked to positive health behaviors and outcomes including increased physical activity and social engagement. Understanding the relationship between social cohesion and urban green space is important for informing holistic approaches to health. In this article, we discuss how positive interactions in urban green space can catalyze social cohesion, social capital and critical health-promoting behaviors that may enhance psychological health and well-being. We also summarize the strengths and limitations of previous studies and suggest directions for future research.

https://www.mdpi.com/1660-4601/16/3/452/pdf

The Relationship between Social Cohesion and Urban Green Space: An Avenue for Health Promotion.

Green spaces and mortality: a systematic review and meta-analysis of cohort studies

BACKGROUND: While risk of outdoor transmission of respiratory viral infections is hypothesized to be low, there is limited data of SARS-CoV-2 transmission in outdoor compared to indoor settings. METHODS: We conducted a systematic review of peer-reviewed papers indexed in PubMed, EMBASE and Web of Science and pre-prints in Europe PMC through August 12 th, 2020 that described cases of human transmission of SARS-CoV-2. Reports of other respiratory virus transmission were included for reference. RESULTS: Five identified studies found that a low proportion of reported global SARS-CoV-2 infections have occurred outdoors (<10%) and the odds of indoor transmission was very high compared to outdoors (18.7 times; 95% CI 6.0, 57.9). Five studies described influenza transmission outdoors and two described adenovirus transmission outdoors. There was high heterogeneity in study quality and individual definitions of outdoor settings which limited our ability to draw conclusions about outdoor transmission risks. In general, factors such as duration and frequency of personal contact, lack of personal protective equipment and occasional indoor gathering during a largely outdoor experience were associated with outdoor reports of infection. CONCLUSION: Existing evidence supports the wide-held belief that the the risk of SARS-CoV-2 transmission is lower outdoors but there are significant gaps in our understanding of specific pathways.

Outdoor Transmission of SARS-CoV-2 and Other Respiratory Viruses, a Systematic Review.

Introduction Natural environments and green spaces provide ecosystem services that enhance human health and well-being. They improve mental health, mitigate allergies and reduce all-cause, respiratory, cardiovascular and cancer mortality. The presence, accessibility, proximity and greenness of green spaces determine the magnitude of their positive health effects, but the role of biodiversity (including species and ecosystem diversity) within green spaces remains underexplored. This review describes mechanisms and evidence of effects of biodiversity in nature and green spaces on human health. Sources of data We identified studies listed in PubMed and Web of Science using combinations of keywords including 'biodiversity', 'diversity', 'species richness', 'human health', 'mental health' and 'well-being' with no restrictions on the year of publication. Papers were considered for detailed evaluation if they were written in English and reported data on levels of biodiversity and health outcomes. Areas of agreement There is evidence for positive associations between species diversity and well-being (psychological and physical) and between ecosystem diversity and immune system regulation. Areas of concern There is a very limited number of studies that relate measured biodiversity to human health. There is more evidence for self-reported psychological well-being than for well-defined clinical outcomes. High species diversity has been associated with both reduced and increased vector-borne disease risk. Growing points Biodiversity supports ecosystem services mitigating heat, noise and air pollution, which all mediate the positive health effects of green spaces, but direct and long-term health outcomes of species diversity have been insufficiently studied so far. Areas timely for research Additional research and newly developed methods are needed to quantify short- and long-term health effects of exposure to perceived and objectively measured species diversity, including health effects of nature-based solutions and exposure to microbiota.

Biodiversity and human health: mechanisms and evidence of the positive health effects of diversity in nature and green spaces.

Background: Over half of the world’s population now lives in urban areas, and this proportion is expected to increase. While there have been numerous reviews of empirical studies on the link between nature and human health, very few have focused on the urban context, and most have examined almost exclusively cross-sectional research. This review is a first step toward assessing the possibility of causal relationships between nature and health in urban settings. Methods: Through systematic review of published literature, we explored the association between urban green space and human health. Results: We found consistent negative association between urban green space exposure and mortality, heart rate, and violence, and positive association with attention, mood, and physical activity. Results were mixed, or no association was found, in studies of urban green space exposure and general health, weight status, depression, and stress (via cortisol concentration). The number of studies was too low to generalize about birth outcomes, blood pressure, heart rate variability, cancer, diabetes, or respiratory symptoms. Conclusions: More studies using rigorous study design are needed to make generalizations, and meta-analyses, of these and other health outcomes possible. These findings may assist urban managers, organizations, and communities in their efforts to increase new or preserve existing green space.

https://www.mdpi.com/1660-4601/15/3/445/pdf

Jaime M. Fluehr

Papers

Urban Green Space and Its Impact on Human Health