At any given moment, the National Aeronautics and Space Administration (NASA) has about two dozen Earth Observation Satellites in orbit. Instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites monitor levels of atmospheric aerosols, including both small and large particles of dust, ash, black carbon, industrial pollutants, and other substances. It is especially important to monitor the concentrations, and sources, of tiny particulate matter (PM2.5), particles smaller than 2.5 micrometers in size that can adversely affect human health, causing or exacerbating conditions like asthma and heart disease. Read Improving NASA Satellite Data with Low-Cost Sensors
