Improving health behaviors through microenvironment changes: the effect of contextualized visual cues on handwashing practices among primary school pupils in Jiujiang City of China

School hand hygiene is essential for reducing infectious diseases transmission, yet routine compliance remains suboptimal. We evaluated whether low-cost, context-embedded “point-of-action” visual cues can improve primary pupils’ handwashing in everyday school routines in China. We conducted a quasiexperimental field study in a public primary school in Jiujiang City. A contextualized visual-cues package (routing footprints, operation icons on sanitizer/tissue devices, and brief risk/procedure posters) was installed in four grade- and sex-designated restrooms serving second graders (≈6–7 years)and sixth graders (≈11–12 years). Correct handwashing before meals and after restroom use was measured via structured observation over a 6-day baseline and a 6-day intervention period. Daily hand-sanitizer and paper-towel consumption was recorded as a system-level corroborative indicator. Effects were estimated using Poisson GLMMs (behavioral outcomes) and LMMs (resource use). The intervention produced robust improvements across contexts (all p < 0.001), increasing the likelihood of correct handwashing before meals (RR = 4.76, 95% CI 3.57–6.25), after restroom use (RR = 2.27, 95% CI 1.82–2.86), and overall (RR = 2.70, 95% CI 2.17–3.33). Gains were age-graded and sex-differentiated in selected contexts, with stronger post-intervention improvements among younger pupils and males for after-restroom and overall outcomes (significant Phase × Grade and Phase × Sex interactions). Resource-use models corroborated behavioral changes, showing higher post-intervention consumption of sanitizer and paper towels (both p < 0.001), with larger increases in second-grade restrooms. Contextualized visual cues integrated into restroom microenvironments can measurably improve school hand hygiene at key moments, particularly among pupils with lower baseline compliance. Given the low unit cost (RMB 206 per cubicle) and minimal implementation burden, point-of-action cue packages may be a scalable complement to classroom-based hygiene education in resource-limited school settings.