Across much of the U.S., people have little way to know when the air they breathe turns dangerous.
Over recent decades, federal funding for public air monitoring has declined, the number of monitors has fallen, and much of the remaining equipment is aging or located far from major polluters.
Now, the stakes are rising: Wildfire smoke is reaching more communities, data centers are adding pollution, and climate-driven heat waves are worsening ozone levels. The Trump administration, meanwhile, has delayed and rolled back requirements meant to hold companies accountable for their emissions…