Researchers saw spikes in hospital visits, inhaler refills and violent crime in areas inundated by wildfire smoke.
Numerous bits of orbiting debris threaten spacecraft, so two teams propose tracking them with unique license plate-like transponders.
Mixtures of chemical pollutants may harm people and wildlife, even when each chemical is below its regulatory threshold.
Low oxygen areas are disappearing almost a month earlier than they did 30 years ago.
Nationwide study shows how manufacturing facilities can increase levels of medical compounds in waterways.