The Costs of Green Space
Green space is not uniformly good for everyone.
- Seasonal breathing difficulty or worsening asthma: see a clinician
What the evidence says
The sources are systematic reviews of environmental harms and of who green space benefits. Legg 2024 (systematic review of 26 papers) reports that people living near green spaces with higher allergenic pollen, real or perceived, experienced worse mental health, and concludes that allergenic pollen may alter mental-health outcomes. Brown 2025 (systematic review) reports green-gentrification pathways, such as rising housing prices and exclusion, linked to negative mental health alongside some benefits of green space. Schüle 2019 (systematic review) reports that, in ecological studies, deprived areas consistently had lower green-space availability, with mixed results in individual-level studies. Aarthi 2023 (systematic review) found no significant association between urban green-space measures and type 2 diabetes. The same sources also report benefits: Rigolon 2021 (systematic review of 90 articles) reports more protective effects for low-SES groups, and Sillman 2022 (systematic review) green space–physical health associations stronger for women. This entry lists the costs beside the benefits and does not weigh them.
- Misconception: 'Green space is good for everyone.' Allergenic exposure and displacement are documented costs.
- Does not diagnose or treat allergy
- Not an argument against green space
- Agreement
- Direction recorded for 0 of 12 sources; not yet recorded for the rest.
- The claim's outcome
- Outcome not yet recorded
- Certainty
- No source states a certainty rating.
- How the sources were read
- Some sources are based on abstracts, not full texts.
What each source measured and concluded (12)
- What it measured
- Risk of all-cause dementia, Alzheimer's disease dementia, vascular dementia, and mild cognitive impairment from environmental risk factors
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Umbrella review and meta-analysis
- Studies and participants, as stated
- 19 reviews containing 37 meta-analyses
- What it measured
- Mental health outcomes
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review
- Studies and participants, as stated
- N=16 articles
- What it measured
- Mental health, behaviour and perceptions related to allergenic pollen in green space
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review
- Studies and participants, as stated
- N=26 papers
- What it measured
- Whether sex/gender modifies green space-physical health associations (CVD, cancer, diabetes, general physical health, respiratory disease, mortality, obesity-related)
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review
- Studies and participants, as stated
- N=62 articles (81 analyses)
- What it measured
- Physical health outcomes.
- How it measured it
- Descriptive statistics (means and standard deviations) of effect modification tests.
- How it was read
- read in full text
- What the review says it includes
- Systematic review of 90 articles
- Studies and participants, as stated
- N=90 studies; total participants not reported
- What it measured
- All-cause mortality.
- How it measured it
- Hazard ratio (HR) and 95% CI.
- Its conclusion, in its own words
- “We found evidence of an inverse association between surrounding greenness and all-cause mortality. Interventions to increase and manage green spaces should therefore be considered as a strategic public health intervention.”
- How it was read
- read in full text
- What the review says it includes
- Meta-analysis of 9 cohort studies
- Studies and participants, as stated
- N=8,324,652 participants across 9 studies
- Heterogeneity, as stated
- Heterogeneity between studies due to different populations and buffer sizes.
- What it measured
- Cardiovascular disease (CVD) events in adults.
- How it measured it
- Objectively measured outcomes (prevalence, incidence, or mortality of CVD conditions).
- How it was read
- read in full text
- What it measured
- Type 2 diabetes prevalence and incidence.
- How it measured it
- Biomedical tests and registry records (objective).
- Its conclusion, in its own words
- “Our systematic review has identified several built environment characteristics, which were significantly related to T2D in Asia, in particular air pollution.”
- How it was read
- read in full text
- What the review says it includes
- Systematic review of 28 studies
- Studies and participants, as stated
- N=482,833 participants across 28 studies (note: this is the largest sample size mentioned for a single study, but the total sample size across all studies is not explicitly provided)
- Heterogeneity, as stated
- Heterogeneity in study design and outcome definitions
- What it measured
- Anti-inflammatory, anti-allergic, anti-asthmatic effects, and increased NK cell activity.
- How it measured it
- Serum cytokine levels (IL-6 and TNFα), immune cell subsets (NK cells and T cells), cytotoxic mediators (objective).
- How it was read
- read in full text
- What the review says it includes
- Systematic review of 33 studies (20 human, 13 animal intervention studies)
- Studies and participants, as stated
- N=not reported participants across 33 studies
- What it measured
- Obesity.
- How it measured it
- Body Mass Index (BMI) (objective).
- How it was read
- read in full text
- What the review says it includes
- Systematic review with meta-analysis of 14 studies
- Studies and participants, as stated
- N=2,067,382 participants across 25 studies
- Heterogeneity, as stated
- High heterogeneity in blue space exposure and health outcome assessments.
- Heterogeneity, as stated
- Potential underestimation of effect sizes due to heterogeneity.
- What it measured
- COVID-19 health outcomes (infection severity, hospitalization, ICU admission, COVID pneumonia, mortality)
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review and meta-analysis (of ecological and non-ecological observational studies)
- Studies and participants, as stated
- 279 studies (38 non-ecological and 241 ecological)
- What it measured
- Social inequalities in availability and accessibility of green and blue spaces
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review
- Studies and participants, as stated
- 14 studies (2010-2017)
Every source below is shown with its study design and links to the original study. This is the audit trail.
“Abstract only” means the review read that paper’s abstract, not its full text; “screened only” means it was included at re-screening and not extracted. Both stay in the trail with their DOI, because how a source was read is part of the audit.