We live in a watery world; 71% of Earth is covered in water. But humans have polluted Earth’s water for decades with pollutants like plastic, oil, and drugs. Marine chemist Chris Reddy guides us through what happens to the ocean during human-caused spills – from the Deepwater Horizon oil spill to the X-Press Pearl plastic spill – and how the ocean recovers.

But our oceans aren’t the only waters at risk of human-caused pollution. Analytical chemist Carrie McDonough transports us to the water in our taps and the ‘forever chemicals’ lurking in them. She demystifies PFAS chemicals, explaining where they come from, where they end up, and the dangers they pose to our environment and human health. This episode is a whirling adventure through the world of water, including the analytical tools chemists use to study it and the looming public health threat of polluted water.

Transcripts and episode sources at acs.org/chainreaction

In the first episode of our series on pollution, we’re turning to the very thing necessary for human life: air. Environmental engineer Pete DeCarlo introduces us first to the tools chemists use to study the air, including the early innovations by chemist Arnold Beckman. These tools alarmed us to the problem of air pollution and its impact on human health, from the smog derived from cars in Los Angeles to the gases escaping from factories in Louisiana, the home of Cancer Alley, an 85-mile industrial stretch between Baton Rouge and New Orleans.

But the threat of air pollution doesn’t just exist outside. During the COVID-19 pandemic, scientists (and the world) woke up to the viruses and particles polluting the air in our homes, office buildings, and schools. Indoor air quality engineer Richard Corsi urges that this indoor air pollution is a public health issue and that cleaning our air through proper ventilation is the way to mitigate this issue. He even created a low-cost way to filter indoor air that you can make at home. This episode is packed with public health crises, ingenious scientific inventions to analyze the unseen, and calls for cleaner air for the health of humanity.

Transcripts and episode sources at acs.org/chainreaction

In this miniseries, Chain Reaction takes listeners on a sweeping journey through the hidden chemistry of pollution—above us, around us, and beneath our feet.

The series begins with the air we breathe, tracing how chemists developed tools to detect invisible pollutants and how those discoveries revealed major public health crises, from urban smog and industrial emissions to the often‑overlooked danger of polluted indoor air.

From the sky, the story flows into water, where marine and analytical chemists unravel how things like plastics and “forever chemicals” move through oceans and drinking water, threatening ecosystems and human health alike.

Then the focus shifts downward, to soil to explore how pollutants accumulate underground and how chemists tackle the complex challenge of remediation.

Finally, we will zoom out to look at the planet as a whole and the systems we need to protect most.

Together, these episodes reveal pollution as a deeply interconnected chemical problem—and show how chemistry is key to understanding, mitigating, and ultimately repairing our planet.

Transcripts and episode sources at acs.org/chainreaction