PM₂.₅ opened a door to public participation addressing environmental challenges in China.

China has long been regarded as a centralized society where the public has little influence on decision-making. Such a top-down management scheme is perceived as a major obstacle to address complicated environment issues. The recent public campaign in China to urge creation of a nationwide PM₂.₅ monitoring network and mitigation plan provides an unprecedented case of how the public participated and influenced policy-making in a centralized society. This paper reviews key incidents in the campaign chronologically. Here we identify information technology, public awareness of air quality's health impacts and the fact air quality affects everyone as public goods as the major factors promoting public participation. This case demonstrates that public participation can happen in a centralized, top-down society such as China. Continued environmental deterioration may stimulate similar campaigns for other issues. We anticipate this essay to be a starting point for more studies on how environmental issues stimulate incremental social change by making people involved in decision-making process, especially in societies where they are rarely able to do so.