Work

Annual recurrence and period-composite persistence of child–heat priority across six contrasting urban systems

Year: 2026

Type: article

Abstract: Urban heat adaptation requires spatial evidence showing where larger child populations coincide with high surface heat, especially where comparable paediatric health records are unavailable. Single-year hotspot maps cannot determine whether priority areas recur annually, persist across multi-year composites or remain reproducible across thermal products. A harmonised 10-year ecological framework was applied to New York, London, Singapore, Nairobi, São Paulo and Brisbane using annual WorldPop estimates for children aged 0–14 years and Landsat warm-season land-surface temperature on a common 1-km hexagonal grid from 2016 to 2025. Within each city-year, child count and heat anomaly were converted to percentile ranks and combined using an equal-weight geometric mean. Cells at or above the 90th score percentile formed the annual priority set. Three continuous periods defined period-composite trajectories, while annual membership quantified recurrence, consecutive runs, transitions, entries and exits. The panel contained 78,300 grid-year observations across 60 city-years. Annual priority sets contained 23.3–44.8% of eligible children across cities and 3.1–30.9 percentage points more children than heat-only sets. Among 10-year common-panel cells, agreement between period-composite persistence and annual membership in at least 8 years was moderate to strong but incomplete (Jaccard = 0.55–0.71). Landsat and MODIS/Terra thermal ranks were positively associated ( ρ = 0.35–0.86), whereas annual upper-decile overlap was only 0.11–0.38. Child concentration, annual recurrence, period-composite persistence and boundary reproducibility therefore represent distinct planning dimensions. The framework supports first-stage prioritisation and local verification but does not estimate individual health risk or causal effects.

Source: Frontiers in Public Health

DOI: 10.3389/fpubh.2026.1984653

Authors: Xin Bian, Shufang Sun

Institutions: Victoria University of Wellington, Shandong Women’s University

Language: English

Topic: Urban Heat Island Mitigation

Subfield: Environmental Engineering

Field: Environmental Science

Domain: Physical Sciences

SDGs: Sustainable cities and communities, Good health and well-being

Open Access status: gold

Estimated APC paid: $3,801