Work

Benefit of residential greenness on visual acuity among 3-year-old children through reduction of exposure to ambient air pollutants

Year: 2026

Type: article

Abstract: A growing body of evidence highlights the health benefits of green space, but underlying mechanisms remain unclear. We hypothesized that the benefits of greenness on children's visual acuity may be mediated through reduced air pollution exposure. This study examined the mediating role of air pollutants in the association between greenness and visual acuity in 3-year-old children. We used data from the Korean Children's Environmental Health Study. Of 5458 cohort participants, 794 children were included. Residential greenness during pregnancy was measured using the Normalized Difference Vegetation Index (NDVI), and PM 2.5 , PM 10 , and NO 2 were estimated with kriging interpolation for the first year after birth. Visual acuity was assessed with Jin’s chart and averaged for both eyes. Associations between NDVI, pollutants, and visual acuity were analyzed using generalized additive models, multivariable regression, and causal mediation analysis. A 1 % increase in z-score– standardized NDVI at 200 m was associated with decreases of 0.25 μg/m³ (95 % CI: –0.31, –0.18), 0.24 μg/m³ (95 % CI: –0.35, –0.22), and 0.55 ppm (95 % CI: –0.61, –0.50) in PM 10 , PM 2.5 , and NO 2 . A 1 % NDVI increase at 200 m was also associated with a 0.023-point (95 % CI: 0.013, 0.032) increase in visual acuity score (1.0 equals 40/40 on Snellen chart). Smaller buffers showed stronger associations. At 200 m, decreases in PM 10 , PM 2.5 , and NO 2 mediated the NDVI–visual acuity relationship, with mediation proportions of 11.6 %, 9.8 %, and 55 %. In two-pollutant models, mediation by both PM 10 and PM 2.5 was no longer significant after adjustment for NO2. These findings suggest that nearby residential greenness may protect visual function in early childhood primarily through reduced exposure to NO 2 . • Residential greenness was associated with better visual acuity in 3-year-old children. • Reductions in PM 10 , PM 2.5 , and especially NO 2 explained up to 55 % of this association. • NO 2 reduction appears to be a key pathway by which greenness supports early vision.

Source: Ecotoxicology and Environmental Safety

DOI: 10.1016/j.ecoenv.2025.119637

Authors: Dajeong Ham, Sung Yeon Kim, Sanghyuk Bae

Institutions: Catholic University of Korea, National Institute of Environmental Research

Language: English

Topic: Urban Green Space and Health

Subfield: Health, Toxicology and Mutagenesis

Field: Environmental Science

Domain: Physical Sciences

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

Open Access status: gold

Estimated APC paid: $3,650