Diagnosing Cross-Media Environmental Risk Governance Gaps: A Hierarchical Topic–Aspect–Frame Framework for Sustainable Environmental Governance

Effective sustainable environmental governance requires feedback between institutional risk management and lived public experience. We propose a hierarchical Topic–Aspect–Frame framework to compare pollution discourse across news and social media. Using 30,635 chunk-level Taiwanese Chinese texts collected from OpView Product Insight in May 2026, treated as an early summer one-month validation window, we analyze topic selection, aspect foregrounding, and frame-based risk construction. Category-balanced audits yielded conditional label precision among analyzable chunks of 91.3% for topics, 85.8% for aspects, and 90.1% for frames. Among 30,304 frame-eligible chunks, Governance/Regulation was more prevalent in news (gap = +4.47 pp; 95% CI = [+3.11, +5.88]), whereas Health and Lived Risk was more prevalent in social media (gap = −9.84 pp; 95% CI = [−10.68, −9.02]). Under the aspect-conditioned prototype design, sequential decomposition attributed the latter gap mainly to topic selection (−5.40 pp) and aspect foregrounding (−4.14 pp), with a smaller within-aspect component (−0.30 pp). Both core directions persisted across four fixed windows and 100 same-fraction subsamples. The framework offers a preliminary, auditable approach for identifying cross-media governance-experience mismatches, subject to seasonal, platform, denominator, and model-support constraints.