Aerosol particles are small solid or liquid particles suspended in the air. They can vary in size from nanometers to micrometers and can be generated naturally (e.g. from dust, sea spray, wildfires) or anthropogenically (e.g. from vehicle emissions, industrial processes). Aerosol particles play a crucial role in the earth's atmosphere, affecting air quality, climate, and human health. Researchers study aerosol particles to understand their sources, properties, transport, and impacts on the environment and human health. This research area involves a multidisciplinary approach that combines atmospheric science, chemistry, physics, and health sciences.