Earth’s atmosphere contains tiny liquid and solid particles called aerosols. Natural aerosol particles, such as dust and sea salt, tend to be larger than human-produced aerosols, such as particle pollution from burning fossil fuels. These aerosol size maps are based on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Green areas show where the aerosols that were present were mostly larger particles. Red areas show where aerosols consisted mostly of small particles. Yellow areas show plumes with an even mix of small and large particles. Gray shows where the sensor did not collect data.
The water vapor maps show the total amount of water vapor in the column of air between the surface and the top of the atmosphere on average for the month. The observations were made by the MODIS sensor on NASA's Aqua satellite. Places where the air was dry are white, while places where water vapor was abundant are blue.