In response to the dramatic increase in air pollution-related illnesses and socioeconomic risks, China has undertaken a large-scale public policy to combat air pollution since 2013. The mass media has become ever since a major actor of this public policy through its important role in diffusing environmental news, and shaping people’s perceptions and emotions regarding air pollution. In this study, we combine the GDELT media emotion database with daily air pollution monitoring data to investigate how the emotional tone in environmental news improves or worsens air quality. We find that more negative emotions in environmental news can decrease air pollution at both the city and county levels, and several robustness checks confirm this effect. Moreover, we discuss two potential mechanisms related to the context of China’s war on air pollution in which the government relies on mass media as an informal regulator of air pollution. We demonstrate that firms reduce their pollution emissions after negative media emotions, and even more in cities that are more prone to environmental sanctions. Building on these results, we propose a reflection on the adoption of effective pro-environmental public policies in line with the SDGs beyond the Chinese context.