Aerosols are minute solid and liquid particles suspended in the atmosphere. Examples include desert dust, sea salt from ocean spray, volcanic ash, smoke from wildfires and emissions from the burning of coal and oil. These tiny particles affect weather and climate, cause hazy skies and can pose serious health hazards. Aerosols also can act as sites for chemical reactions, such as those that lead to the destruction of stratospheric ozone, i.e., the ozone hole.