Socio-environmental risks are associated to accelerated modernization and industrialization, where the population has been affected by its consequences. In this case, the risks associated to air contamination are closely tied to basal operations of modern society, to human action, to our daily activities, and to an administration thereof habitually mediated by governmental institutions that are supposed to "visibilize" the risk and manage actions designed to minimize their occurrence. This article explores the manner in which, and the consequences of, a communication of risks to the community faced with atmospheric contamination, stemming from a study of two cities of intermediate size in the south of Chile. Methodologically, interviews and focus groups were used; secondary information was analyzed, and a content analysis was applied via Atlas.ti software which, under a comparative approach, permitted us to observe the instruments and strategies in the process of "visibilization" and "comprehension" of risk.