ESRI Research Bulletin ESRI Research Bulletin Articles provide short summaries of work published by ESRI researchers and overviews of thematic areas covered by ESRI programmes of research. Bulletin Articles are designed to be easily accessible to a wide readership. A reference or references to the full publication is included at the start of each Bulletin article. February 7, 2018 Exposure to radon gas is thought to be the second most important cause of lung cancer worldwide after smoking.