atmosphere

Beijing power plant

Globe-trotting pollutants pose a larger threat to public health than previously thought

Polycyclic aromatic hydrocarbons, toxic air pollutants produced by combustion, are linked to lung cancer and other serious health problems. Recent findings suggest that these tiny particles travel long distances and significantly increase overall health risks.

Globe-trotting pollutants pose a larger threat to public health than previously thought
clouds

Bacteria are thriving in the sky — and they influence the weather

Bacteria are thriving in the sky — and they influence the weather
The moonset behind Earth, as viewed from the International Space Station.

Some of the oxygen on the moon used to be on planet Earth

Some of the oxygen on the moon used to be on planet Earth