Something far worse than acid rain now falls from the sky all the time

Decades ago, acid rain was one of the world’s most alarming environmental crises. Pollution from coal power plants and cars made rainfall so toxic that it killed fish, wiped out forests, and even eroded buildings. Fortunately, governments passed laws to reduce sulfur dioxide and nitrogen oxide emissions.

But now, there’s an even scarier problem. And this time, there’s no easy fix. Scientists have discovered that rainfall worldwide is now contaminated with microplastics—tiny plastic particles that may pose serious risks to human health and the environment. To make matters worse, this microplastic rain may even be contaminated with “forever chemicals,” too.

We may have once believed plastic pollution was mainly a problem for landfills and oceans. However, in recent years, researchers have found microplastics everywhere, including in rainfall. Some research has even found microplastics in some of the world’s most remote and untouched areas, like Antarctica.

A 2020 study found over 1,000 metric tons of plastic particles falling onto national parks and wilderness areas in the Western U.S. every year. That’s equivalent to 300 million plastic water bottles raining down from the sky. Another study from 2023 highlighted even more trouble with plastics in the rain, further solidifying the trouble we’re in.

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Researchers found that highways were one of the biggest sources of the materials found in microplastic rain. As cars drive over roads, they grind down plastic waste, tire particles, and other synthetic fibers. These tiny bits float into the air and later fall with rain. The oceans also play a part, releasing microplastics into the atmosphere as waves crash together and bubbles full of microplastics burst into the air.

Along with microplastic rain, scientists have detected PFAS (perfluoroalkyl and polyfluoroalkyl substances)—or “forever chemicals”—in rainwater worldwide. These chemicals are used in nonstick cookware, water-resistant fabrics, and food packaging. They’re incredibly persistent and don’t break down easily. While we’ve found some ways to remove forever chemicals from water, it’s hard to say how easily those methods might transfer to removing them from the atmosphere.

Studies show that rainwater in the U.S., Sweden, China, and even Antarctica contains PFAS at levels higher than what’s considered safe for drinking water. Unlike acid rain, we can’t simply regulate emissions to stop it. With microplastic rain, the damage has already been done, and there doesn’t appear any way to really stop it.