Although too small to be seen with the human eye, atmospheric particulate matter has major impacts on the world around us, from our health to global climate. Understanding the sources, properties, and transformations of these particles in the atmosphere is among the major challenges in air quality and climate research today. Significant progress has been made over the past two decades in understanding atmospheric aerosol chemistry and its connections to climate. Advances in technology for characterizing aerosol chemical composition and physical properties have enabled rapid discovery in this area. This article reviews fundamental concepts and recent developments surrounding ambient aerosols, their chemical composition and sources, light-absorbing aerosols, aerosols and cloud formation, and aerosol-based solar radiation management (also known as solar geoengineering).
Keywords: air quality; atmospheric chemistry; chemical engineering; environment; geoengineering.