Green Space Exposure Research Articles

Ambient heat and emergency department visits for mental health in Canada: assessing temporal variations by greenspace, urbanicity and socioeconomic status

BACKGROUND AND AIM Although previous research has suggested that greenspace might attenuate health risks associated with ambient heat, there is limited research on mental health disorders. Thus, we evaluated the effect modification of greenspace on heat-related mental health emergency department (ED) visits and whether these effects changed over time. METHODS We conducted a case-crossover study for mental health-related ED visits in Canada between 2004 and 2021 during warm-season months (May to August). ED visits for all Canadians living in 111 health regions were included. Daily average temperature as well as greenspace exposure, estimated by the Normalized Difference Vegetation Index (NDVI), were assigned to individuals at their residential location. Extreme heat was defined as the 95th percentile of the health region-specific warm-season temperature distribution. Conditional logistic regression was used to estimate associations between heat and mental health-related ED visits. RESULTS A total of 10,638,372 ED visits for any mental health condition were included. Days of extreme heat were associated with an increased risk of ED visits for any mental health condition (OR = 1.07; 95% CI: 1.05-1.09). In the earlier part of the study period (2004–2009), the associations between ambient heat and mental health ED visits were stronger among individuals exposed to the lowest quartile of NDVI exposure (OR = 1.20; 95% CI: 1.15-1.25), compared to individuals in the highest quartile of NDVI (OR = 1.01; 95% CI: 0.96-1.07). This difference, however, accentuated in the later part of the study (2016-2021) with the ORs for regions in the lowest quartile of NDVI increasing to 1.29 (95% CI: 1.25-1.34) and remaining stable for regions in the highest quartile. Effects appeared strongest in the most deprived socioeconomic areas. CONCLUSIONS Potential health benefits of greenspaces should be considered in mitigation strategies regarding the impacts of climate change on mental health ED visits.

Association of Greenspace Exposure at Midlife with Cognitive Decline Later in Life in a Study of US Women

Background and aim: Greenspace may slow cognitive decline by increasing opportunities for physical activity and social connection or reducing stress or air pollution. However, studies on the association between greenspace and cognitive decline are sparse. We investigated the prospective association between greenspace at midlife and cognitive decline later in life. Methods: Using data from the US-based Nurses’ Health Study (mean age=61y), we assessed residential greenspace in a 270m buffer as the cumulative average from 1986 to 1994 using Landsat Normalized Difference Vegetation Index data. We examined 16,352 women who were enrolled in a substudy starting in 1995-2001 (74y) through 2008. Participants underwent up to four repeated measures of five cognitive tests. A global composite score was calculated as the average of all z-scores for each task to evaluate overall cognitive functioning. We evaluated the association between greenspace and subsequent cognitive decline using linear mixed models adjusted for age, education, neighborhood socioeconomic status, and depression. Results: In fully adjusted models, those living in the highest quintile of greenspace had an annual slope of decline that was slower by 0.01 units of the global composite score (95%CI 0.00001, 0.012) compared to those in the lowest quintile. To help interpret this estimate, we find that one year of age is related to a -0.01 unit mean annual difference for global cognition; thus, more greenspace appeared equivalent to slowing cognitive aging by one year. We found similar associations for the Telephone Interview for Cognitive Status (TICS); participants living in the highest greenspace quintile had an annual rate of decline that was slower by 0.04 units in the TICS score (95%CI 0.01, 0.07) compared to those in the lowest quintile. Conclusions: Higher greenspace exposure in early adulthood is associated with a slower rate of cognitive decline later in life in this cohort of US women.

Early Life Exposure to Greenspace and Autism Spectrum Disorder and the Mediating Effects of Air Pollution in Ontario, Canada

BACKGROUND AND AIM Early life exposure to greenspace is associated with health benefits on childhood development, but the pathways of this relationship are not completely understood. This study aimed to evaluate early life exposure to different greenspace metrics on the development on autism spectrum disorder (ASD) and whether these associations are mediated by reductions in ambient air pollution. METHODS This case-control study included 1,801 ASD cases and 9002 controls less than 5 years of age identified from 2012 to 2017 using health administrative databases in the province of Ontario, Canada. Greenspace metrics were estimated using the Normalized Difference Vegetation Index (NDVI), Green View Index (GVI) and percent tree canopy coverage using values within 250 m of participants’ residential postal codes at birth. Conditional logistic regression was used to investigate associations between greenspace exposure and ASD while adjusting for maternal age, parity, maternal comorbidities, substance use (i.e. smoking and alcohol), socioeconomic status and urbanicity. We estimated the mediation effects of nitrogen dioxide (NO2), fine particulate matter (PM2.5), and ozone (O3) using causal mediation analyses. RESULTS In the adjusted model, we found that one interquartile range (IQR) increase in percentage tree canopy was associated with a 6% reduction in the odds of ASD (Odds ratio = 0.94; 95% CI: 0.90, 0.98). No associations were found for NDVI and GVI in relation to ASD. We found that 81.8% (77.6 – 85.9), 20.1% (16.6 – 23.6) and 13.6% (11.1 – 16.0) of the association between tree canopy exposure and ASD was mediated through reductions in NO2, PM2.5, and O3, respectively. CONCLUSIONS Early life exposure to greenspace might reduce the risk of ASD through reductions in ambient air pollution, in particular traffic pollution from NO2. Our findings may provide support to communities on the potential health benefits of greenspaces.

Association between greenspace exposure and different domains of cognitive function in the French CONSTANCES cohort

BACKGROUND AND AIM Greenspace has been suggested to be associated with better cognitive function in adults. We assessed the association between residential surrounding greenspace and different domains of cognition in the French CONSTANCES cohort. METHODS We included 76,482 participants aged 45 and older, who performed tests at enrollment (2012-2019) on three cognitive domains: episodic memory (fast free and cued recall), language skills (semantic and lexical fluency), and executive functions (digit-symbol substitution, trail making test part A and B [TMT-A and TMT-B]), and a global cognitive score (a composite of these six tests). Residential surrounding greenspace was quantified using satellite-based Normalized Difference Vegetation Index (NDVI) at 300m buffer around the participant’s home in the enrollment year. We modeled the cross-sectional associations for urban, suburban, isolated cities, rural, and Paris separately, using multiple linear regressions on standardized outcomes (TMT-A and TMT-B were log-transformed) adjusted for age, sex, education, recruitment center, neighborhood deprivation, and air pollution. RESULTS The participants were 57.6±7.2 years old, 54.9% women, and 49.7% with university education. Average NDVI at 300m buffer (IQR: 0.26) was 0.58±0.14, 0.67±0.12, 0.71±0.11, 0.81±0.08, and 0.35±0.09 for urban, suburban, isolated cities, rural, and Paris respectively. We found significant beneficial association between residential surrounding greenspace and semantic fluency at urban, suburban, isolated cities, and rural areas (ß=0.048 [95% CI: 0.018, 0.079], 0.068 [0.037, 0.098], 0.105 [0.033, 0.177], 0.096 [0.033, 0.158] respectively). We also observed similar beneficial associations for executive functions in urban and suburban areas. No associations with greenspace were found for episodic memory, lexical fluency, and global cognitive score in most communes of residence. CONCLUSION Exposure to greenspace could be beneficial for cognition, especially semantic and executive functions, in adults. Urban and suburban residents probably gain more cognitive benefits from greenspace. KEYWORDS Natural environment; Cognitive function; Alzheimer’s disease; Environmental epidemiology

Environmental health impacts and inequalities in green space and air pollution exposures in six European cities

BACKGROUND The GoGreenRoutes project (Horizon 2020/869764) aims to introduce co-created nature-based solutions (NBS) as interventions to enhance access to green space in six medium-sized European cities (Burgas, Lahti, Limerick, Tallinn, Umea, and Versailles). We analyzed the spatial distribution and health impacts associated with unequal exposure to air pollution and green space prior to the implementation of these NBS interventions in each city. METHODS We retrieved air pollution (NO₂ and PM₂.₅) and green space (NDVI and % Green Area proxies) data at a 250m x 250m grid-cell level for each city, in addition to population and mortality data for 2015. We compared baseline exposures to WHO guidelines and calculated the exposure differences at the grid-cell level. We applied a comparative risk assessment methodology to estimate the mortality burden attributable to not achieving the WHO guidelines. We evaluated exposures and attributable mortality distributions and their associations to understand current urban environmental inequalities. RESULTS We found high variability in air pollution and green spaces levels between and within all six cities. Around 60% of the population lacked green space and 90% of the population were exposed to air pollution above WHO guidelines. Overall, we estimated a city range between 3-37 and 2-71 deaths/100,000 persons were attributable to exceedances in WHO NO₂ and PM₂.₅ limit values, respectively; 4-13 deaths/100,000 persons were associated with lack of Green Area; and 18-35 deaths/100,000 persons were linked to NDVI levels below the city target. Green space and air pollution were highly spatially correlated, likewise their attributable burdens. CONCLUSIONS Our results suggest that urban populations in the analyzed cities are affected simultaneously by lack of green space and increased air pollution. We expect NBS interventions will contribute to reducing the environmental health burden and inequalities in the GoGreenRoutes cities. KEYWORDS Health impact assessment; urban health; health equity; nature-based solutions.

Investigation on sociodemographic and health inequity of greenspace using different greenspace indicators in 3 US urban communities

BACKGROUND AND AIM Study results are inconclusive regarding how greenspace exposure differs by sociodemographic status potentially due to lack of consideration of varying dimensions of greenspace. We investigated the inequity of greenspace and its health effects by sociodemographic status comparing various greenspace metrics. METHODS We used five metrics: vegetation levels measured by Enhanced Vegetation Index (EVI), percent greenspace, percent tree cover, percent tree cover along walkable roads, and percent people living <500m of a park entrance (park accessibility). We used data for 2008–2013 in Census block groups in 3 US regions: New Haven, Connecticut; Baltimore, Maryland; Durham, North Carolina. We examined associations between each greenspace metric and indicators of income, education, linguistic isolation, race/ethnicity, and age. Logistic regressions examined associations between these greenspace metrics and age-standardized mortality controlling for sociodemographic indicators. RESULTS The region with the highest greenspace differed across metrics. Average percent greenspace was highest in Durham and lowest in Baltimore. Average percent people living <500m of a park entrance and percent tree cover along walkable roads were highest in New Haven. An interquartile range (64.7%) increase in people of color was associated with a 6.2% (95%CI: 3.1–9.3) increase in park accessibility, whereas it was associated with 0.03–7.3% decreases in other greenspace metrics. A 15.5% increase in the lower-education population was associated with a 2.1% increase (95%CI: -0.3%–4.6%) in park accessibility but decreases with other greenspace metrics (0.02–5.0%). The odds ratios of having an all-cause standardized mortality rate ≥75th percentile were inversely associated with all greenspace metrics except for park accessibility (OR=1.40, 95% CI: 0.52–3.75). CONCLUSIONS Environmental justice concerns and health benefits of greenspace can differ by form of greenspace and socioeconomic status within communities. Comparisons of greenspace between different greenspace metrics should be incorporated in decision-making. KEYWORDS Environmental justice, greenspace, health inequity.

Addressing Geographic Uncertainty: Greenness and Depression Incidence in a Prospective Cohort Study of US Women

BACKGROUND AND AIM: Geographic uncertainty, including uncertainty in the selection of a spatial scale for exposure, may bias health effect estimates. For example, studies showed protective associations of residential greenspace exposure with depression, but there is no standardized approach for selecting the appropriate buffer sizes to examine this association. By applying a novel statistical approach, we aimed to empirically identify buffer sizes and simultaneously report effect estimates in a longitudinal analysis of greenness and depression. METHODS: We followed Nurses’ Health Study cohort participants who were free of depressive symptoms at baseline (2000) and who reported doctor-diagnosed depression, antidepressant use, and important depression risk factors on biennial questionnaires from 2000 to 2016 (n = 41,945). We used high-resolution (30m x 30m) Landsat data to assess annual average greenness in multiple buffer sizes around participants’ residential addresses: 90m, 150m, 270m, 510m, 750m, 990m, 1230m, 1500m, and 2100m. We used penalized Cox regression to estimate regression coefficients to identify buffers within which greenness was associated with risk of depression. Specifically, we modeled NVDI effects as a function of buffer size using B-splines, while adopting a group bridge penalty to identify relevant buffers, with an additional penalty to smooth the effect estimate curves. RESULTS: Over 449,139 person-years follow-up, 5,454 incident cases occurred. Greenness was protectively associated with incident depression after adjusting for confounders. Our penalized approach identified greenness within the buffer distance of 150m around the residential address as the most relevant for depression incidence, with a 2% decrease in depression risk for each 0.1 increase in NDVI (95% CI 0.3%, 3.6%) within the 150m empirically identified buffer area. CONCLUSIONS: To account for geographic uncertainty in assessing the impact of greenness on incident depression, we applied a novel statistical approach to identify that NDVI exposure within 150m was associated with lower risk of depression.

Long-Term Exposure to Greenspace and Cognitive Function during the Lifespan: A Systematic Review.

Recent advances in environmental psychology highlighted the beneficial role of greenspace exposure on cognition. We conducted a systematic review of the available studies on the association of long-term exposure to greenspace and cognitive functions across the lifespan. PRISMA guidelines and the PECOs method were applied to screen for eligible studies. Twenty-five studies from Scopus, PubMed, and PsycINFO met the inclusion criteria. Six studies were longitudinal and nineteen cross-sectional. Fifteen studies focused on schoolchildren, six studies on adults, and four on the elderly. Twenty studies used the NDVI to assess greenspace exposure and the remaining used other indexes. Eight studies employed academic achievement as the outcome, eight studies global cognition, six studies attention/executive functions, and three studies memory. The evidence was inconsistent but suggestive for a beneficial role of greenspace exposure on cognitive functions. Further studies are required, especially among adults and older people, by adopting longitudinal designs.

Reading Greenness in Urban Areas: Possible Roles of Phenological Metrics from the Copernicus HR-VPP Dataset

Vegetation phenology is that branch of science that describes periodic plant life cycle events across the growing seasons. Remote sensing typically monitors these significant events by means of time series of vegetation indices, permitting to characterize vegetation dynamics. It is well known that vegetation in urban areas, i.e., green spaces in general, may benefit human health mainly by mitigating noise and air pollution, promoting physical or social activities, and improving mental health. Based on the influence that green space exposure seems to exert on Public Health and using a multidisciplinary approach, we mapped phenological behavior of urban green areas to explore yearly persistence of their potential favorable effect, such as heat reduction, air purification, noise mitigation, and promotion of physical/social activities and improvement of mental health. The study area corresponds to the municipality of Torino (about 800,000 inhabitants, NW, Italy). Renouncing to a rigorous at-species level phenological description, this work investigated macro-phenology of vegetated areas for the 2018, 2019 and 2020 years with reference to the new free and open Copernicus HR-VPP dataset. Vegetation type, deduced with reference to the 2019 BDTRE official technical map of the Piemonte Region, was considered and related to the correspondent macro-phenology using a limited number of metrics from the HR-VPP dataset. Investigation was aimed at exploring their capability of providing synthetic and easy-to-use information for urban planners. No validation was achieved about phenological metrics values (assuming their accuracy correspondent to the nominal one reported in the associated manuals). Nevertheless, a spatial validation was operated to investigate the capability of the dataset to properly recognize vegetated areas, thus providing correspondent metrics. Preliminary results showed a spatial inconsistency related to the HR-VPP dataset, that greatly overestimates (about 50%) vegetated areas in the city, assigning metric values to pixels that, if compared with technical maps, do not fall within vegetated areas. The work found out that, among HR-VPP metrics, LOS (Length Of Season) and SPROD (Seasonal Productivity) well characterized vegetation patches, making it possible to clearly read vegetation behavior, which can be effectively exploited to zone the city and make management of green areas and real estate considerations more effective.

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

IntroductionPsychological 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. MethodGreenspace 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. ResultsWe 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. ConclusionWe 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 association between prenatal greenspace exposure and Autism spectrum disorder, and the potentially mediating role of air pollution reduction: A population-based birth cohort study.

Autism spectrum disorder (ASD) incidence has increased in past decades. ASD etiology remains inconclusive, but research suggests genetic, epigenetic, and environmental contributing factors and likely prenatal origins. Few studies have examined modifiable environmental risk factors for ASD, and far fewer have examined protective exposures. Greenspace has been associated with positive child development, but very limited greenspace research has examined ASD risk or prenatal exposures. Only one ecological study in 2017 has evaluated the association between greenspace and ASD, observing protective benefits. Greenspace may have direct effects on ASD risk and indirect effects by reducing air pollution exposure, a growing suspected ASD risk factor. To measure the association between prenatal greenspace exposure and ASD risk and examine if reduced air pollution levels in areas of higher greenspace mediate this association. We linked a population-based birth cohort of all deliveries in Metro Vancouver, Canada, from 2004 to 2009, with follow-up to 2014. Diagnoses were based on Autism Diagnostic Observation Schedule and Autism Diagnostic Interview-Revised instruments. Greenspace was quantified as the average of the annual mean Normalized Difference Vegetation Index (NDVI) within a 250m buffer of a residential postal code. Air pollutant exposures-particulate matter with a diameter less than 2.5µm (PM2.5), nitric oxide (NO), and nitrogen dioxide (NO2)-were derived from previously developed and temporally adjusted land use regression models. We estimated air pollutant exposures as the mean concentration per month during pregnancy. We calculated odds ratios (ORs) using logistic regression per NDVI interquartile range (IQR) increase, adjusting for child sex, birth month and year, maternal age and birthplace, and neighborhood-level urbanicity and income. To estimate the health impact of greenspace on ASD at the population level, we used the logistic regression model and marginal standardization to derive risk differences (RDs). Lastly, to quantify the mediating effect of greenspace on ASD risk through air pollution reduction, we used marginal structural models and a potential outcomes framework to calculate marginal risk differences (RDs) to decompose the total effect of greenspace on ASD into natural direct and indirect effects. Of 129,222 births, 1,921 (1.5%) children were diagnosed with ASD. The adjusted OR for ASD per NDVI IQR (0.12) increase was 0.96 (95% CI: 0.90, 1.02) in 250m buffer zones and 0.94 (95% CI: 0.89, 1.00) in 100m buffer zones. On the additive scale, the adjusted RDs were null. Natural direct, natural indirect, and total effect RDs were null for PM2.5, NO, and NO2 mediation models. Prenatal greenspace exposure was associated with reduced odds of ASD, but in the additive scale, this effect was null at the population level. No mediating effect was observed through reduced air pollution, suggesting that air pollution may act as a confounder rather than as a mediator.

Keynote 2

Title of HEPA 2022 Keynote presentationPhysical activity, air pollution, and much more: the case for systems thinking in urban policies.Description of HEPA 2022 Keynote presentationPhysical activity may be one of greatest benefits of active travel -however there are many more, and in some cases there could be some trade-offs too. Yet, we create disjointed targets, campaigns and regulations to tackle in siloed and often piecemeal approaches major urban health and environmental challenges such as climate change, physical inactivity, air pollution, traffic injuries, social isolation, stress, inequalities, etc. The way we address these problems matters, and this lack of joined up thinking is a wasted opportunity. If we let the promotion of a healthier, more sustainable and resilient society be the goal of our policies rather than merely compliance with singularly focused standards and targets, we will find different types of solutions emerge as most advantageous. For example, in addition to providing a seamless way to integrate physical activity into daily routines, walking and cycling can be a convenient and low-cost alternatives to driving, thus reducing air pollution, green house gas emissions and noise; the infrastructure and urban design features conducive to walking and cycling may in turn have further benefits, such as traffic safety and greenspace exposure; etc. Evidence on benefits, co-benefits, and trade-offs of different types of urban policies that tackle some of our greatest urban health challenges jointly will be presented, making the case for holistic approaches to urban policy decision making, particularly through urban planning and design strategies. We will end by discussing avenues for greater integration of health in urban decision making.

The impact of black carbon (BC) on mode-specific galvanic skin response (GSR) as a measure of stress in urban environments

Previous research has shown that walking and cycling could help alleviate stress in cities, however there is poor knowledge on how specific microenvironmental conditions encountered during daily journeys may lead to varying degrees of stress experienced at that moment. We use objectively measured data and a robust causal inference framework to address this gap. Using a Bayesian Doubly Robust (BDR) approach, we find that black carbon exposure statistically significantly increases stress, as measured by Galvanic Skin Response (GSR), while cycling and while walking. Augmented Outcome Regression (AOR) models indicate that greenspace exposure and the presence of walking or cycling infrastructure could reduce stress. None of these effects are statistically significant for people in motorized transport. These findings add to a growing evidence-base on health benefits of policies aimed at decreasing air pollution, improving active travel infrastructure and increasing greenspace in cities.

Exploring the impacts of street-level greenspace on stroke and cardiovascular diseases in Chinese adults

In recent years, cardiovascular diseases (CVDs) have become the primary cause of death in the world. Existing studies have found that greenspace is important for the prevention of CVDs and stroke. However, since they only focus on large green infrastructure (e.g., urban parks) or the general greenspace (usually being evaluated through normalized difference vegetation index), little information exists regarding the association between street-level greenspace and CVDs (stroke). In this study, the CVDs and stroke data of participants were retrieved from the 33 Chinese Community Health Study. We measured participants’ exposure to street-level greenspace exposure using street view images and machine learning technique. Multilevel logistic regressions were applied. While controlling for confounders, we found that higher level of street-level greenspace exposure was associated with lower CVDs prevalence. However, street-level greenspace exposure was associated with stroke prevalence only for females. The associations were stronger among females, younger adults, participants with educational attainment above high school, physically active participants and participants who were not overweight. None of the mediators (air pollution, physical exercise, and BMI) can explain the associations between street-level greenspace exposure and CVDs (stroke) prevalence. Our findings suggest that street-level vegetation should be increased to cope with the rapid growth of the CVDs burdens. Also, the differences between the effect of street-level trees and grasses should be noted before formulating specific urban planning policies.

Contrasting inequality in human exposure to greenspace between cities of Global North and Global South

The United Nations specified the need for “providing universal access to greenspace for urban residents” in the 11th Sustainable Development Goal. Yet, how far we are from this goal remains unclear. Here, we develop a methodology incorporating fine-resolution population and greenspace mappings and use the results for 2020 to elucidate global differences in human exposure to greenspace. We identify a contrasting difference of greenspace exposure between Global South and North cities. Global South cities experience only one third of the greenspace exposure level of Global North cities. Greenspace exposure inequality (Gini: 0.47) in Global South cities is nearly twice that of Global North cities (Gini: 0.27). We quantify that 22% of the spatial disparity is associated with greenspace provision, and 53% is associated with joint effects of greenspace provision and spatial configuration. These findings highlight the need for prioritizing greening policies to mitigate environmental disparity and achieve sustainable development goals.

Does childhood exposure to biodiverse greenspace reduce the risk of developing asthma?

The prevalence of inflammatory diseases is increasing in populations throughout the industrialized world. An increasing proportion of human populations grow up and live in urban areas, probably with reduced exposure to biodiversity, including diverse soil biotas. Decreased exposure to microorganisms from natural environments, in particular in early childhood, has been hypothesized to hamper development of the human immune system and lead to increasing risks of inflammatory diseases, such as asthma.We investigated 40,249 Danish individuals born 1995–2015. Percentage greenspace was assessed in a 2 km buffer around home addresses of individuals. The Danish Biodiversity Map, charting occurrence density of red-listed animals, plants and macrofungi, was used as a proxy for multi-taxon biodiversity.For asthma defined broadly, we found no evidence of decreasing risk of developing asthma with higher levels of biodiversity, while greenspace exposure was associated with higher risk of asthma. In contrast, exposure to total and biodiverse greenspace was associated with reduced risk of developing severe asthma. Exposure to farmland, which in Denmark is heavily industrialized cropland, also showed association with elevated risk of developing asthma, even at relatively low agricultural landcover. In the subset of children growing up in highly urbanized settings, we found high exposures to urban greenspace to be associated with reduced risk of developing asthma.Our results lend limited support to the hypothesis that childhood exposure to biodiverse environments reduces the risk of acquiring inflammatory diseases later in life. However, access to urban greenspace, such as parks, which typically harbour low levels of biodiversity, seems to reduce asthma risk, potentially through exposure to common soil microbiota. Our results suggest that effects of biodiversity exposure on human health is set by a balance between ecosystem services and disservices and that biodiversity conservation is best motivated with other arguments than reduction of risks from inflammatory diseases.

Beyond green environments: Multi-scale difference in human exposure to greenspace in China.

Greenspace exposure metrics can allow for comparisons of green space supply across time, space, and population groups, and for inferring patterns of variation in opportunities for people to enjoy the health and recreational benefits of nearby green environments. A better understanding of greenspace exposure differences across various spatial scales is a critical requirement for lessening environmental health disparities. However, existing studies are typically limited to a single city or across selected cities, which severely limits the use of results in measuring systemic national and regional scale differences that might need policy at above individual city planning level. To close this knowledge gap, our study aims to provide a holistic assessment of multi-scale greenspace exposure across provinces, cities, counties, towns, and land parcels for the whole of China. We mapped the nationwide fractional greenspace coverage at 10m with Sentinel-2 satellite imagery, and then modeled population-weighted greenspace exposure to examine variation of greenspace exposure across scales. Our results show a prominent scaling effect of greenspace exposure across multi-scale administrative divisions in China, suggesting, as expected, an increase in heterogeneity with finer spatial scales. We also identify an asymmetric pattern of the difference between greenspace exposure and greenspace coverage, across a geo-demographic demarcation boundary (i.e., along the Heihe-Tengchong Line). In general, the greenspace coverage rate will overestimate more realistic human exposure to greenspace in East China while underestimating in West China. We further found that, in China, more recently urbanized areas have much better greenspace exposure than older urban areas. Our study provides a spatially explicit greenspace exposure metric for discovering multi-scale greenspace exposure difference, which will enhance governments' capacity to quantify environmental justice, detect vulnerable greenspace exposure risk hotspots, prioritize greenspace management at the supra-city scale, and monitor the balance between greenspace supply and demand.

Examining the Influence of Housing Conditions and Daily Greenspace Exposure on People's Perceived COVID-19 Risk and Distress.

Many people have worried about COVID-19 infection, job loss, income reduction, and family conflict during the COVID-19 pandemic. Some social groups may be particularly vulnerable due to their residential neighborhoods and daily activities. On the other hand, people’s daily exposure to greenspace offers promising pathways for reducing these worries associated with COVID-19. Using data collected with a questionnaire and a two-day activity diary from two typical neighborhoods in Hong Kong, this study examines how people’s housing conditions and daily greenspace exposure affect their perceived COVID-19 risk and distress (i.e., worries about job loss, income reduction, and family conflict) during the pandemic. First, the study compares people’s perceived COVID-19 risk and distress based on their residential neighborhoods. Further, it examines the associations between people’s perceived COVID-19 risk and distress with their housing conditions and daily greenspace exposure using ordinal logistic regression models. The results indicate that living in a high-risk neighborhood, being married, renting a residential unit, and living in a large household are significantly associated with a higher neighborhood-based perceived COVID-19 risk and distress during the pandemic. In addition, people also reported lower mobility-based perceived COVID-19 risk when compared to their neighborhood-based perceived COVID-19 risk, while they still have a high perceived COVID-19 risk in their occupational venues if they have to work in a high-risk district (e.g., Kowloon). Lastly, daily greenspace exposure (i.e., woodland) could reduce people’s perceived COVID-19 risk and distress. These results have important implications for the public health authority when formulating the measures during the COVID-19 pandemic.

Characterizing the provision and inequality of primary school greenspaces in China’s major cities based on multi-sensor remote sensing

Environmental and green justice problems occur globally, especially in cities with unequal access to urban greenspaces. Recently, inequality in school greenspaces has drawn growing attention, given the importance of campus green environments in young students’ health and academic performance. However, the commonly used Normalized Differences Vegetation Index (NDVI) method for measuring greenspace from satellite imagery is hindered by the saturation issue and tend to underestimate greenspace at high vegetation cover areas, causing large uncertainties in greenspace inequality studies at a national scale. Besides, despite the progress on the inequality of public greenspace exposure, our understandings of primary school greenspace provision and inequality, as well as the driving factors, for young students in a developing world (e.g., China) is still limited. To address these issues, we first adapted a spectral unmixing technique based on multi-sensor remote sensing for more accurate measurements of greenspace provision. Then, we evaluated the provision and inequality of greenspace for 19,681 primary schools in China’s 31 major cities and examined the driving factors using an integrated path analysis. Our findings revealed that: (1) Our proposed multi-sensor remote sensing-based method for greenspace measurement is reliable across our study area with a R2 of 0.81 and RMSE of 0.14; in contrast, the traditional NDVI-based greenspace measurement saturated at the range of 0.7–1.0, leading to much lower accuracy (a R2 of 0.72 and RMSE of 0.24). (2) Most of the cities under study had low to moderate levels of inequality in primary school greenspace (Gini index < 0.5), but the overall greenspace provision was relatively low; Five cities under study facing high inequality in greenspace exposure (Gini index ≥ 0.5) as well as low greenspace provision (mean fraction cover < 0.25). (3) The monthly maximum temperature and the mean cover of greenspace in primary schools were identified as variables directly affecting the inequality in primary school greenspace (R2 = 0.76, p-value < 0.05), whereas the city-level government revenue manifests its effects through the mean cover of greenspace in primary schools and city-level mean greenspace cover. By developing a novel framework for examining the provision and inequality of greenspace in all primary schools in China’s major cities, our study provides valuable insights for designing and evaluating school greening programs in support of healthier learning environment development for next generations.

The Benefits of Green-Space Exposure on Fifteen Health Outcomes: A Meta-Analysis

The main objective of this research is to quantify evidence of the impact of green-space on fifteen health outcomes. Four databases- MEDLINE, EMBASE, AMED and CINAHL from January, 2000 to June, 2019 were searched. In this meta-analysis 63 observational studies were included for the investigation where 15 health outcomes (e.g., Type-2 Diabetes, Incidence of Hypertension, Incidence of Asthma, Stroke, Preterm Birth, Cardiovascular Mortality, All-cause Mortality, Salivary Cortisol and self-identified well-being etc) are considered. Our meta-analysis results revealed increased green-space exposure is associated with decreased heart rate (standardized mean difference (SMD)=−0.67), salivary cortisol (SMD = −0.31), along withreduced risk of preterm birth (OR = 0.87), type II diabetes (OR =0.76), hypertension (OR =0.77), coronary heart disease (OR = 0.85), all-cause mortality (OR = 0.69), cardiovascular mortality (OR =0.82), and an increased incidence of self-identified well-being (OR =1.15). Green-space exposure is found to be connected with the above mentioned health outcomes. Dhaka Univ. J. Sci. 69(3): 143-148, 2022 (June)