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 fire maps show the locations of actively burning fires around the world on a monthly basis, based on observations from the MODIS sensors on NASA's Terra satellite. The colors are based on a count of the number (not size) of fires observed within a 1,000-square-kilometer area. White pixels show the high end of the count — as many as 30 fires in a 1,000-square-kilometer area per day. Orange pixels show as many as 10 fires, while red areas show as few as 1 fire per day.