On Sept. 15, the eruption of Mount Anak Krakatau sent volcanic ash up to 15,000 meters (50,000 feet) and produced rumbling heard 700 kilometers (435 miles) away. Eight airports suspended operations, thousands of flights were disrupted, and more than 270,000 passengers were stranded.

Nearly two-thirds of the American public say climate change is increasing the risk of respiratory diseases and heat- and insect-related illnesses, according to a new survey from the Annenberg Public Policy Center (APPC) of the University of Pennsylvania.

From 22,000 miles above, the new instrument lets researchers and regulators track airborne health threats in near real time, on a continental scale