His research focuses on the environmental determinants of cardiovascular disease, including in China. Much of his work has examined the effects of ambient air pollution on the risk of cardiovascular events and its effects on cardiovascular physiology. In the context of these studies, he has used tools from the fields of epidemiology and toxicology to: 1) evaluate the association between environmental exposures and disease, 2) identify subgroups of the population that may be particularly susceptible, and 3) elucidate the physiologic mechanisms for the observed effects. Wellenius has served as a research consultant to the Chinese government’s Center for Disease Control (CDC), and is currently engaged with the Chinese CDC in collaborative empirical research.