I have a long-term interest in studying the health effects of various environmental and occupational agents, including ambient particulate matter (PM), cigarette smoke, and engineered nanoparticles such as nickel, cobalt, and  CuO nanoparticles. I mainly focus on their toxic, genetic, epigenetic, and carcinogenic effects and the underlying mechanisms. I received the Walter A. Rosenblith New Investigator Award from the Health Effects Institute in 2006. My laboratory has been supported by grants from NIH, American Heart Association, American Lung Association, Health Effects Institute, Kentucky Science & Engineering Foundation, Kentucky Lung Cancer Research Program, etc. I have been an ad hoc or regular grant reviewer for the Medical Research Council of United Kingdom, NIH, The Peer Reviewed Medical Research Program (DoD), California Tobacco-Related Disease Research Program, and National Natural Science Foundation of China. I have published over 100 articles in peer-reviewed journals, reviews, and book chapters. As a member of the IARC Working Group, I participated in preparing Volume 131 of the IARC Monographs “Cobalt, Antimony Compounds, and Weapons-grade Tungsten Alloy” (2023). I am the Editor of the Book “Nanotoxicology Methods and Protocols”, part of the book series "Methods in Molecular Biology" (MIMB, volume 1894).