Co-benefits are seen as a key factor for overcoming the problems of collective action and extended time horizons holding back mitigation of global warming. The mechanism behind this hypothesis is that public acceptance of mitigation policies constitutes a crucial limiting factor, necessitating ancillary gains such as clean air for mitigation policy to be politically robust. However, the public's preference for local pollution mitigation and concomitant failure to appreciate the benefits of global warming mitigation is assumed rather than demonstrated. In this paper, we show, first, that people distinguish between the physical manifestations of air pollution and global warming, and second, that they see both phenomena as arising from the same causes as well as having negative impacts on humans. Specifically, using a survey experimental design with open-ended questions in an urban Chinese setting, we demonstrate that citizens relate glacier melt and sea-level rise to global warming, while linking the local phenomenon of smog almost exclusively to air pollution. At the same time, respondents link impacts on humans and vehicle/industrial pollution topics with both air pollution and global warming. These findings are relevant to decision-makers as they suggest that the public values mitigation of global warming in its own right. Our novel method may shed new light on a range of issues relating to energy, the economy, and environmental issues.