Stratospheric aerosols are minute particles suspended in the atmosphere designed for solar radiation management [SRM]. When these particles are sufficiently large, their presence becomes noticeable as they scatter and absorb sunlight, which can reduce visibility [haze] and redden sunrises and sunsets.
Aerosols interact both directly and indirectly with the Earth’s radiation budget and climate. As a direct effect, the aerosols scatter sunlight directly back into space. As an indirect effect, aerosols in the lower atmosphere can modify the size of cloud particles, changing how the clouds reflect and absorb sunlight, thereby affecting the earth’s energy budget.
Aerosols can also act as sites for chemical reactions to take place. Stratospheric aerosols introduce small, reflective particles into the upper atmosphere to reflect some sunlight before it reaches the surface of the Earth. This is accomplished by releasing sulfur dioxide into the stratosphere.