The Great London Smog of 1952

It might seem like smog is a first world problem: Glamorous movie stars in Los Angeles, say, stuck in fancy cars that spew out enough emissions to obscure the Hollywood sign. Of course, smog is actually a problem in cities all over the world. But a smog that enveloped London in 1952 — long before cars were clogging freeways as they do today — wreaked havoc on the city and practically brought life to a standstill.

The Great London Smog wasn't your typical "ugh, it looks gross out there" few days. According to MetLink, "The smoke-like pollution was so toxic it was even reported to have choked cows to death in the fields. It was so thick it brought road, air and rail transport to a virtual standstill."

How it Happened

It all started Dec. 5, 1952, when a rather more typical smog hung in the air during the day. But by nightfall, the smog had thickened to a heavy, sulfurous smelling fog. While normally warm air near the ground rises up through the cold air above it, the air in London near the ground ended up becoming cooler than the air above it — a thermal inversion. All the smoke and pollution from houses, industry, you name it — it was all trapped near the ground. When mist formed in the layer of cold air, the sun couldn't reach the ground to begin the evaporation process. The mucky pollutants were left to hang in the air, where condensed water clung to them and created an acid fog.

And it's not like the chilly December weather was doing them any favors. According to MetLink, "The weather in November and early December 1952 had been very cold, with heavy snowfalls across the region. To keep warm, the people of London were burning large quantities of coal in their homes. Smoke was pouring from the chimneys of their houses."

What resulted was five days of somewhat apocalyptic conditions. Visibility was at a meter (or about 3 feet) by Sunday, and people literally couldn't see their own feet. Driving was nearly impossible, so abandoned vehicles clogged the roads. It stayed like that for days until the wind finally came to the rescue and blew the fog down the Thames and out to the North Sea on Tuesday, Dec. 9.

But it wasn't exactly a quick fix. First of all, a "normal" death toll for London during that time period would've been 1,852 people. During the smog days, 4,703 people died. And death tolls stayed at elevated levels for months afterward, as those with lung conditions or health problems continued to be affected by the incident.