In December 1952, a dense fog fell over London that lasted 4 days. This “Great Smog” lead to the death of roughly 12,000 people.
What the heck happened. Now, more than 60 years later, an international team of researchers have figured it out. While researching China’s modern air pollution issues, they determined that people were breathing in the fog equivalent of acid rain.
Read about it (and our potential future!) over at Science Alert!