Exploring uncharted territory: Do urban greenspaces support mental health in low- and middle-income countries?

A systematic review of audit tools for evaluating the quality of green spaces in mental health research

Research showing the relationship between exposure to green space and health has yielded conflicting results, possibly due to the oversight of green space quality in quantitative studies. This systematic review, guided by the PRISMA framework (registered under Prospero ID CRD42023279720), focused on audit tools for green space quality in mental health research. From 4028 studies, 13 were reviewed, with 77 % linking better mental health outcomes to higher green space quality. Eight tools, especially Public Open Space and Dillen et al. tools demonstrated strong correlations with mental health. Certain green space qualities like grass, pathways, and water elements showed positive health associations. Future research should aim for standardized quality metrics and robust methodologies to support causal inferences and efficient assessments.

Exposure to urban green spaces and mental health during the COVID-19 pandemic: evidence from two low and lower-middle-income countries

Introduction

The COVID-19 pandemic has had a significant impact on mental health globally, with limited access to mental health care affecting low- and middle-income countries (LMICs) the most. In response, alternative strategies to support mental health have been necessary, with access to green spaces being a potential solution. While studies have highlighted the role of green spaces in promoting mental health during pandemic lockdowns, few studies have focused on the role of green spaces in mental health recovery after lockdowns. This study investigated changes in green space access and associations with mental health recovery in Bangladesh and Egypt across the pandemic.

Methods

An online survey was conducted between January and April 2021 after the first lockdown was lifted in Bangladesh (n = 556) and Egypt (n = 660). We evaluated indoor and outdoor greenery, including the number of household plants, window views, and duration of outdoor visits. The quantity of greenness was estimated using the normalized difference vegetation index (NDVI). This index was estimated using satellite images with a resolution of 10x10m during the survey period (January-April 2021) with Sentinel-2 satellite in the Google Earth Engine platform. We calculated averages within 250m, 300m, 500m and 1000m buffers of the survey check-in locations using ArcGIS 10.3. Multiple linear regression models were used to evaluate relationships between changes in natural exposure and changes in mental health.

Results

The results showed that mental health improved in both countries after the lockdown period. People in both countries increased their time spent outdoors in green spaces after the lockdown period, and these increases in time outdoors were associated with improved mental health. Unexpectedly, changes in the number of indoor plants after the lockdown period were associated with contrasting mental health outcomes; more plants translated to increased anxiety and decreased depression. Refocusing lives after the pandemic on areas other than maintaining indoor plants may assist with worrying and feeling panicked. Still, indoor plants may assist with depressive symptoms for people remaining isolated.

Conclusion

These findings have important implications for policymakers and urban planners in LMICs, highlighting the need to increase access to natural environments in urban areas to improve mental health and well-being in public health emergencies.

Advancing urban green and blue space contributions to public health

Urban green and blue spaces (UGBS) have the potential to improve public health and wellbeing, address health inequities, and provide co-benefits for the environment, economy, and society. To achieve these ambitions, researchers should engage with communities, practitioners, and policy makers in a virtuous circle of research, policy, implementation, and active citizenship using the principles of co-design, co-implementation, co-evaluation, and co-translation. This Viewpoint provides an integrated perspective on the challenges that hinder the delivery of health-enhancing UGBS and recommendations to address them. Our recommendations include: strengthening the evidence beyond cross-sectional research designs, strengthening the evidence base on UGBS intervention approaches, evaluating the effects on diverse population groups and communities, addressing inequities in the distribution and quality of UGBS, accelerating research on blue space, providing evidence for environmental effects, incorporating co-design approaches, developing innovative modelling methods, fostering whole-system evidence, harnessing political drivers, creating collaborations for sustainable UGBS action, and advancing evidence in low-income and middle-income countries. The full potential of UGBS as public health, social, economic, and environmental assets is yet to be realised. Acting on the research and translation recommendations will aid in addressing these challenges in collaboration with research, policy, practice, and communities.

Does the quality of street greenspace matter? Examining the associations between multiple greenspace exposures and chronic health conditions of urban residents in a rapidly urbanising Chinese city

BACKGROUND

Numerous studies have demonstrated that greenspace(GS) exposure is associated with health improvements in individuals with hypertension and diabetes. However, studies examining the associations between multiple GS exposures and chronic health conditions in developing countries are limited.

METHODS

Geospatial data and spatial analysis were employed to objectively measure the total neighbourhood vegetative cover (mean value of normalised difference vegetation index [NDVI] within specific buffer zone) and proximity to park-based GS (network distance from home to the entrance of park-based GS). Street view imagery and machine learning techniques were used to measure the subjective perceptions of street GS quality. A multiple linear regression model was applied to examine the associations between multiple GS exposures and the prevalence of hypertension and diabetes in neighbourhoods located in Qingdao, China.

RESULTS

The model explained 29.8% and 28.2% of the prevalence of hypertension and diabetes, respectively. The results suggested that: 1) the total vegetative cover of the neighbourhood was inversely correlated with the prevalence of hypertension (β = -0.272, p = 0.013, 95% confidence interval (CI): [-1.332, -0.162]) and diabetes (β = -0.230, p = 0.037, 95% CI: [-0.720, -0.008]). 2) The street GS quality was negatively correlated with the prevalence of hypertension (β = -0.303, p = 0.007, 95% CI: [-2.981, -0.491]) and diabetes (β = -0.309, p = 0.006, 95% CI: [-1.839, -0.314]). 3) Proximity to park-based GS and the prevalence of hypertension and diabetes mellitus were not significantly correlated.

CONCLUSIONS

This study used subjective and objective methods to comprehensively assess the greenspace exposure from overhead to eye level, from quantity, proximity to quality. The results demonstrated the beneficial relationships between street GS quality, total vegetative cover, and chronic health in a rapidly urbanising Chinese city. Furthermore. the effect of street GS quality was more pronounced in potentially mitigating chronic health problems, and improving the quality of street GS might be an efficient and effective intervention pathway for addressing chronic health issues in densely populated cities.

Changes in cortisol and dehydroepiandrosterone levels immediately after urban park visits

The purpose of this study is to explore physiological and psychological changes immediately after a short-term visit to urban parks in an uncontrolled condition. Sixty park visitors completed a short questionnaire evaluating their subjective well-being (SWB) and donated a saliva sample immediately before and after their park visit. In addition, participants wore a pedometer to track their physical activity level during the park visit. Results indicated the levels of all biomarkers (cortisol, dehydroepiandrosterone [DHEA], and cortisol/DHEA ratio) decreased while SWB scores increased after the park visit. The duration of park visit was identified as a key variable significantly associated with cortisol reduction, and changes in SWB scores after the park visit were significantly associated with changes in cortisol level. A park visit duration of 21.8 min has the predictive ability to discriminate park visitors who exhibit reductions in cortisol levels after the park visit from those who do not.

The association between urban greenspace and psychological health among young adults in Addis Ababa, Ethiopia

INTRODUCTION

Psychological disorders are emerging as health priorities in Sub-Saharan Africa, specifically Ethiopia. Urban greenspace - parks, trees, and other vegetation integrated into urban form - may facilitate population psychological health, but is largely understudied outside high-income countries. We explore greenspace in relation to psychological health among young adults in Addis Ababa, Ethiopia.

METHOD

Greenspace exposure was calculated using the normalized difference vegetation index (NDVI) derived from publicly available satellite imagery (2018-2019). We used tests of spatial clustering to characterize greenspace distribution. Derived NDVI values were linked to Positive Outcomes for Orphans study participants to explore cross-sectional associations between greenspace exposure and psychological health (measured 2019-2021). Two continuous scores of psychological health were examined: total difficulties from the Strengths and Difficulties Questionnaire and depressive symptoms from the 8-item Patient Health Questionnaire. Multilevel generalized linear regression, nested by administrative units, was used to estimate the association between greenspace and psychological health. We also explored effect modification by gender and having income.

RESULTS

We found greenspace is spatially clustered in Addis Ababa, with high greenspace density in the northeast region and low greenspace density in the center of the city. Our findings suggest residing in greener areas is associated with fewer emotional and behavioral difficulties (β = -1.89; 95% CI: -3.50, -0.29), but not significantly associated with depressive symptomology (β = -0.61; 95% CI: -2.33, 1.11). We observed stronger associations between greenspace and total difficulties among those reporting any income and among males, and for the association between greenspace and depression symptomology among males.

CONCLUSION

We offer initial exploration into the role of greenspace in psychological well-being in Addis Ababa, with potential implications for urban communities across Sub-Saharan Africa. Further research should continue to explore how the built and natural environment could be leveraged in similar settings to promote population psychological health.

The relationship between greenspace and personal exposure to PM2.5 during walking trips in Delhi, India

The presence of urban greenspace may lead to reduced personal exposure to air pollution via several mechanisms, for example, increased dispersion of airborne particulates; however, there is a lack of real-time evidence across different urban contexts. Study participants were 79 adolescents with asthma who lived in Delhi, India and were recruited to the Delhi Air Pollution and Health Effects (DAPHNE) study. Participants were monitored continuously for exposure to PM_2.5 (particulate matter with an aerodynamic diameter of less than 2.5 μm) for 48 h. We isolated normal day-to-day walking journeys (n = 199) from the personal monitoring dataset and assessed the relationship between greenspace and personal PM_2.5 using different spatial scales of the mean Normalised Difference Vegetation Index (NDVI), mean tree cover (TC), and proportion of surrounding green land use (GLU) and parks or forests (PF). The journeys had a mean duration of 12.7 (range 5, 53) min and mean PM_2.5 personal exposure of 133.9 (standard deviation = 114.8) μg/m³. The within-trip analysis showed weak inverse associations between greenspace markers and PM_2.5 concentrations only in the spring/summer/monsoon season, with statistically significant associations for TC at the 25 and 50 m buffers in adjusted models. Between-trip analysis also indicated inverse associations for NDVI and TC, but suggested positive associations for GLU and PF in the spring/summer/monsoon season; no overall patterns of association were evident in the autumn/winter season. Associations between greenspace and personal PM_2.5 during walking trips in Delhi varied across metrics, spatial scales, and season, but were most consistent for TC. These mixed findings may partly relate to journeys being dominated by walking along roads and small effects on PM_2.5 of small pockets of greenspace. Larger areas of greenspace may, however, give rise to observable spatial effects on PM_2.5, which vary by season.

Impact of COVID-19 Lock-Downs on Nature Connection in Southern and Eastern Africa

The response of African countries immediately after the COVID-19 pandemic declaration was rapid and appropriate, with low infections and mortality rates until June 2020. Severe lock-down measures were effective in Africa; however, the reduction in the amount of natural experience influences the quality of life in modern society. This study is conducted as an international comparative study in five African countries on changes in the perception of health recovery and outdoor activities in urban forests during the COVID-19 pandemic. An online survey was conducted with 430 respondents to investigate the relationships between COVID-19 stress, indoor activity, appreciation of greenspaces, perception of health recovery, and use of greenspaces. A structural equation model was used for analysis. The visit frequency and staying time in urban forests after lock-down dramatically decreased, raising concerns about nature-deficit disorder across the target countries after the end of the pandemic. This study confirmed urban dwellers’ desire for natural experiences and health recovery during the pandemic and predicts an explosive increase in urban forest utilization after the pandemic has ended.

What Happens in Your Brain When You Walk Down the Street? Implications of Architectural Proportions, Biophilia, and Fractal Geometry for Urban Science

This article reviews current research in visual urban perception. The temporal sequence of the first few milliseconds of visual stimulus processing sheds light on the historically ambiguous topic of aesthetic experience. Automatic fractal processing triggers initial attraction/avoidance evaluations of an environment’s salubriousness, and its potentially positive or negative impacts upon an individual. As repeated cycles of visual perception occur, the attractiveness of urban form affects the user experience much more than had been previously suspected. These perceptual mechanisms promote walkability and intuitive navigation, and so they support the urban and civic interactions for which we establish communities and cities in the first place. Therefore, the use of multiple fractals needs to reintegrate with biophilic and traditional architecture in urban design for their proven positive effects on health and well-being. Such benefits include striking reductions in observers’ stress and mental fatigue. Due to their costs to individual well-being, urban performance, environmental quality, and climatic adaptation, this paper recommends that nontraditional styles should be hereafter applied judiciously to the built environment.

Designing Age-Friendly Communities: Exploring Qualitative Perspectives on Urban Green Spaces and Ageing in Two Indian Megacities

The World Health Organization and the United Nations have increasingly acknowledged the importance of urban green space (UGS) for healthy ageing. However, low- and middle-income countries (LMICs) like India with exponential ageing populations have inadequate UGS. This qualitative study examined the relationships between UGS and healthy ageing in two megacities in India. Participants were recruited using snowball sampling in New Delhi and Chennai and semi-structured interviews were conducted with consenting participants (N = 60, female = 51%; age > 60 years; fluent in English, Hindi, or Tamil). Interviews were recorded, transcribed, translated, and analysed using inductive and thematic analysis. Benefits of UGS included community building and social capital, improved health and social resilience, physical activity promotion, reduced exposure to noise, air pollution, and heat. Poorly maintained UGS and lack of safe, age-friendly pedestrian infrastructure were identified as barriers to health promotion in later life. Neighbourhood disorder and crime constrained older adults' use of UGS in low-income neighbourhoods. This study underscores the role of UGS in the design of age-friendly communities in India. The findings highlight the benefits of UGS for older adults, particularly those living in socially disadvantaged or underserved communities, which often have least access to high-quality parks and green areas.