Pollution is only one way humans are altering our planet. There’s climate change, sea level rise, biodiversity loss, and much more. Earth system scientists, including biological oceanographer Katherine Richardson, developed the nine planetary boundaries, a framework to understand what Earth systems are critical for life, and what will happen if human-caused changes to our planet continue. Katherine unpacks these boundaries, revealing how chemistry sits at the heart of both the problems and solutions to the equilibrium of many of these critical systems. It’s a sobering yet hopeful look at humanity’s future on a finite planet.

Transcripts and episode sources at acs.org/chainreaction

Water and air pollution may capture the headlines, but there’s another threat looming beneath our feet: soil. We farm on it, build cities on it, and pull water from it. But pollutants from industrial waste, mining, and trash settle in soil, wreaking havoc on existing ecosystems and threatening our food and water supply. Soil and environmental chemist Owen Duckworth shares how chemists study soil, the unique qualities of soil pollutants, and the role chemists play in protecting public health.

After understanding what’s polluting our soil, then comes the difficult task of cleaning up those pollutants. Biogeochemist William Burgos discusses the little known world of soil remediation, including storing waste in landfills or allowing adaptable microbes to slowly remediate pollutants on their own. This episode transports you to the Superfund sites, old mining caves, and acid pits where waste hides away, and reveals chemistry’s role in understanding — and fixing — soil pollution.

Transcripts and episode sources at acs.org/chainreaction

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

In this special bonus episode of Chain Reaction, meet the voices behind the American Chemical Society’s newest chemistry podcast. Host and producer Margot Wohl and executive producer Sam Jones introduce themselves, share their journeys from science research to science communication, and explain why Chain Reaction by ACS exists in the first place.

Sam talks about launching ACS’s long‑running podcast Tiny Matters and her path from biomedical research to podcasting, while Margot shares her background in neuroscience and animal behavior, and her long‑standing love of audio storytelling.

Along the way, you'll hear about butterfly genitals that sense light, an egg‑shaped electric car designed by a dentist, and learn about upcoming miniseries on medicines, energy and transportation, and pollution.

Transcripts and episode sources at acs.org/chainreaction

For 150 years, the American Chemical Society has been a pillar of the chemistry field, supporting students and professionals through major world events and scientific developments. The 2025 president of ACS, Dorothy Phillips, joins to discuss the future of the society while also bringing us along on her trailblazing journey through chemistry.

Transcripts and episode sources at acs.org/chainreaction

For centuries, chemistry in the United States was for one kind of a person: The white man. But now, after decades of progress, chemistry is more inclusive than ever.

Historian Laura Puaca reveals how wars, feminist movements, and shifting societal expectations opened long‑closed doors for women in science. As feminism changed women's role in chemistry, other social movements were advancing the causes of minority scientists. Chemist and educator Sibrina Collins highlights the stories of early Black chemists, the vital role of HBCUs, and the creation of NOBCChE to provide community and opportunity amid systemic exclusion. And chemistry lecturer Barbara Belmont recounts the fight for LGBTQ+ visibility in chemistry, leading to the creation of Out to Innovate and ACS’s LGBTQ+ Chemists and Allies Subdivision. Together, their stories show how representation, advocacy, and community continue to reshape the chemical enterprise.

Transcripts and episode sources at acs.org/chainreaction