Aerosols are tiny solid or liquid particles suspended in air, ranging in size from nanometers to micrometers. They can come from natural sources such as dust, sea spray, and volcanic eruptions, as well as human activities like industrial processes and vehicular emissions. Aerosols play a crucial role in climate change by scattering and absorbing sunlight, as well as serving as cloud condensation nuclei and affecting cloud properties. Research in this area focuses on understanding the sources, composition, transport, and impacts of aerosols on human health, air quality, and the Earth's climate system.