According to the latest report by the World Health Organization, air pollution, one of the planet's most dangerous environmental carcinogens, has become one of the leading causes of cancer-related deaths. In China this is a particularly crucial issue, with more than 100 cities and close to one billion individuals threatened by haze due to heavy air pollution in recent years. Beyond traditional channels, the rise of social media has led to greater online haze-related information sharing. Formative research suggests that Weibo is playing a larger role in the process of information seeking than traditional media. Given the severity of haze and the influential role of Weibo, a textual analysis was conducted based on Sina Weibo (Chinese Twitter) to provide health decision-makers and media consumers knowledge on how environmental health issues such as haze are framed in Chinese social media. Framing theory served to explain the differences across various outlets: People's Daily, China Daily, and the Chinese version of the Wall Street Journal. By analyzing 407 Weibo posts, five major frames emerged: (1) governmental concern, (2) public opinion and issue management, (3) contributing factors and effects, (4) socializing haze-related news, and (5) external haze-related news.