Acceptability of Hanoi's planned low-emission zone: Rankings, spatial heterogeneity, and entropy sensitivity

Municipal governments are introducing low-emission zones (LEZs) to improve environmental quality. Their success depends on both effective regulation and public acceptability. This study examines spatial variation in the pre-implementation acceptability of Hanoi's planned LEZ and whether association-based and entropy-based rankings address the same policy question. Of 685 survey respondents, 648 passed an outcome-blind response-quality screen. The study finds that acceptability was modestly positive (mean 3.286/5), although favourable item responses remained below 50%. Positive affect (ρ=0.687), value alignment (ρ=0.641), adaptability (ρ=0.603), and air-quality concern (ρ=0.584) showed the strongest Spearman associations. Positive affect, adaptability, and air-quality concern remained significantly associated with acceptability after adjustment for demographic and mobility characteristics. Acceptability differed across locality groups (ε²=0.044); residence in a listed ward remained negatively associated with acceptability after adjustment for demographic and mobility characteristics (β=-0.310), but the association weakened after attitudinal variables were added (β=-0.088, p=0.194). Spearman and adjusted mutual-information rankings agreed (rₛ=0.918), whereas entropy rankings changed with normalisation and coding. Targeted engagement should combine credible air-quality evidence with feasible mobility support. The findings indicate associations and are not representative of the population.