摘要：Ba c k g r o u n d: A large and growing literature investigating the role of extreme heat on mortality has conceptualized the role of ambient ozone in various ways, sometimes treating it as a confounder, sometimes as an effect modifier, and sometimes as a co-exposure. Thus, there is a lack of consensus about the roles that temperature and ozone together play in causing mortality.oB j e c t i v e s: We applied directed acyclic graphs (DAGs) to the topic of heat-related mortality to graphically represent the subject matter behind the research questions and to provide insight on the analytical options available.di sc u s si o n: On the basis of the subject matter encoded in the graphs, we assert that the role of ozone in studies of temperature and mortality is a causal intermediate that is affected by tempera-ture and that can also affect mortality, rather than a confounder.co n c l u s i o n s: We discuss possible questions of interest implied by this causal structure and pro-pose areas of future work to further clarify the role of air pollutants in epidemiologic studies of extreme temperature
