Cloud products are used as an input for retrieving air pollutant information from environmental satellites, especially for calculating the air mass factor (AMF) that is applied to convert the slant column density into the vertical column density of gaseous pollutants observed by satellite.

① Effective cloud fraction has a value between 0 and 1. Larger values indicate greater reflection of solar light by clouds. ② Cloud centroid pressure means the cloud altitude in a unit of pressure (i.e., hPa) indicating the reflected sun light by clouds. It has a maximum value of 1013 hPa, and larger values mean lower cloud altitude. ③ The cloud radiance fraction ranges from 0 to 2, and larger values indicate greater reflection of sunlight at each wavelength. Cloud information produced by environmental satellite is an optical quantity observed in the ultraviolet region, and is not consistent with physical characteristics of clouds.