Back when I was a kid, life was pretty simple. Saturday morning cartoons were awesome, Ecto Cooler was abundant and the Soviet Union collapsed before they could drop any nukes on us. I couldn’t watch the news, or even my cartoons, though, without being reminded that there were other problems out there. Namely, a hole in the ozone layer and acid rain falling from the sky (which, in my mind at the time, meant the world was going to start melting).

Scary and omnipresent as they were then, these two environmental disasters don’t make headlines like they used to. Ethan checked in on the ozone layer earlier this year, but what became of acid rain? We fixed it. Kind of.

What is Acid Rain?

Acid rain, according to the Environmental Protection Agency, is what you get when chemical emissions from man-made and natural sources (primarily sulfur dioxide (SO2) and nitrogen oxides (NOx) from fossil fuel combustion) go up into the atmosphere and react with water, oxygen, and other chemicals to form acidic compounds and then come back town as acidic rain, snow, sleet, or fog.

To my relief, the stuff doesn’t melt buildings or people instantly, but it can corrode certain building materials, and fine sulfate and nitrate particles can be inhaled, causing inflammation and damage to tissues in the circulatory and respiratory systems. It also wreaks havoc on plants and animals, turning water too toxic for fish and tweaking soil chemistry so it can’t support plant life.

Acid rain started to disappear from the public mind in the 1990s, when the government strengthened environmental regulations. A 1990 amendment to the Clean Air Act required reductions in the types of emissions that led to acid rain, by way of cap-and-trade programs like the EPA’s  Clean Air Interstate Rule (CAIR) and the Acid Rain Program (ARP) and technology like smokestack “scrubbers” and low NOx burners. Emissions began to fall dramatically and are now millions of tons lower than they were in the late 80s and early 90s.

That’s great for us, and acid rain is long gone from the plot lines of American cartoons, but it’s still a problem elsewhere in the world. In some countries, particularly China, lax regulation and expanding industrialization and fossil fuel use led to an increase in acid rain-forming emissions and instances of acid rain in the early 2000s. More recently, the Chinese have begun to turn things around by shutting down smaller, inefficient coal power plants and retrofitting larger ones with sulfur dioxide scrubbers and emissions-monitoring equipment.