An unplanned experiment when wildfire smoke rolled through Colorado shows how trees keep some of the smoke out.

HCFCs were a temporary replacement for CFCs, the initial subject of the 1987 Montreal protocol.

For decades, big-box retailers have evaded federal regulation of the pollution their operations generate. But a new air emission rule in Southern California could become a model for state controls.

Some ancient texts record what were likely dying stars, faintly visible from Earth. If close enough, these events can disturb telescopes and even damage the ozone layer.

So much pollution goes into the air today that even without wildfire smoke, 99% of the global population breathes unhealthy air.

The UK space launch failed but it succeeded in releasing hazardous pollutants to multiple layers of the atmosphere.

The new global air quality guidelines are the World Health Organization’s first update since 2005. Scientists know far more now about the serious risks these pollutants pose to human health.

Depending on who you ask, the northern lights may, very occasionally, sound like ‘rustling silk’ or ‘two planks meeting flat ways’.

Here's what a space tourism industry led by Branson, Bezos and Musk might mean for the planet.

Exaggerating how much lockdown improved air quality could allow us to underestimate the scale of the air pollution problem.