With 7 of its most ambitious rules for cars, trucks and trains repealed, California officials now must find new ways to clean up the nation’s worst air pollution. But officials face growing pushback ...

Air pollution used to be much worse. In October of 1948, a thick, choking smog settled over the small Pennsylvania town of Donora. The town was home to two steel plants.

We typically spend 80% of our time indoors, where the quality of the air we breathe depends on the age and type of building we occupy, as well as indoor pollution and outdoor pollution sources.

New technologies including recoverable satellites and in-orbit space debris recycling could help solve the satellite air pollution problem and prevent a new ecological crisis in the future.