Small amounts of condensed matter in the atmosphere, often originated from the incomplete combustion of coal and oil or from dust storms and also generated from anthropogenic sources like mining or metallurgy. Some portion of these particles are suspended in air--depending on atmospheric conditions--causing the warming or the cooling of atmosphere by changing the amount of radiation that reaches the earth's surface. Particles composed of black carbon, or soot for instance, warm the atmosphere by absorbing sunlight and heating the surrounding air. Other particles scattering sunlight back to space resulting in a cooling of the atmosphere.