Cross-crisis effects of COVID-19 on air pollution risk perception and mental stress.

Against the backdrop of a rapidly evolving multi-crisis era, the COVID-19 pandemic raises critical questions about how acute shocks may reconfigure perceptions of persistent environmental risks. Drawing on two representative surveys in Nanjing before (2018-2019, n = 508) and during (2022, n = 500) the pandemic, triangulated with geotagged Nanjing Weibo posts (2019-2022) and the World Risk Poll (2019; 2021), this study develops three theoretical models and tests eight hypotheses. Results reveal clear cross-crisis effects: COVID-19 significantly reduced perceived air-pollution risks, consistent with a finite-pool-of-worry account. This decline partially offset stress, yet the pandemic still produced a net increase in mental stress by introducing additional psychological burdens. Although COVID-19 reduced average daily PM2.5 exposure and increased capacity-based trust in air-pollution governance, neither mediated changes in risk perception. Crucially, the crisis amplified the negative impact of perceived physical symptoms on mental well-being, heightening vulnerability under crisis conditions. These findings show how acute crises spill over to reshape chronic risk perception and psychological consequences. They underscore the importance of integrating environmental governance with compound risk communication and timely mental health support. The conclusions are transferable to other compound crises, including future pandemics, extreme weather events, or environmental emergencies, offering valuable lessons for strengthening societal resilience.