Introduction: Problems, Policies and Technologies

This introductory chapter provides perspective on the global and regional contexts of the problems posed by the emissions. The focus is on climate change and public health problems—and therefore on the kinds of emissions that contribute to those problems. The chapter addresses the enduring issues: What are the emissions’ chemical and physical features that are problematic? What are their effects on public health and climate change? What policies and technologies can mitigate the emissions? Black carbon (BC) receives special attention—both because it is one of the three most potent climate change forcing agents—along with carbon dioxide and methane—and because it is a worldwide public health problem causing millions of deaths per year. The coronavirus pandemic in 2020 and the global economic recession, of course, suddenly reduced the levels of emissions of all types—a topic that is considered in the final chapter. The following six chapters provide more detailed mode-specific, industry-specific and country-specific analyses of the emissions as well as mitigation policies and technologies.