After talking about improvements of air quality in some cities, today we want to remember possibly one of the worst days for breathing in the world’s entire history, when on July 26, 1943 a “gas attack” hit the city of Los Angeles. 77 years later, this event is still remembered by many, and should be a warning for all of us.

First contact with “the beast”

The air smelled like bleach. Noses ran and eyes stung. Visibility was cut down to three city blocks. Photos of Los Angeles taken on this day in 1943 show a city shrouded in thick, biting smog. In the midst of World War II, people thought the city was under attack. But as they’d discover, they were just having the first experience of a new phenomenon that would become one of L.A.’s defining characteristics.

“As residents would later find out, the fog was not from an outside attacker, but from their own vehicles and factories,” writes Jess McNally for Wired. “Massive wartime immigration to a city built for cars had made L.A. the largest car market the industry had ever seen. But the influx of cars and industry, combined with a geography that traps fumes like a big bowl, had caught up with Angelenos.”

Here’s how Chip Jacobs and William J. Kelly described this dark day in Angeleno history in the first line of their essential book, Smogtown: “The beast you couldn’t stab fanned its poison across the waking downtown.”  The “beast” was smog.

Smog filled air in LA

The causes

Air pollution from industrial sources had been building for decades: the L.A. City Council first took action trying to limit industrial pollution in 1905. But in the summer of 1943, everybody’s eyes watered. Cars swerved through the soup. It felt like the air got bad all at once.

Industrial smoke had elicited complaints in Los Angeles since at least 1903, wrote Cone, but what one government report referred to as a “hellish cloud” was something much more significant. The problem until the 1940s, she wrote, was that nobody knew exactly what smog was (nitrogen oxide and volatile organic compounds – both found in fuels – mix with sunlight to form ground-level ozone, plus tiny particles of matter from fossil fuels) or how it was caused. Summertime worsened all this, even though it took a little while longer for our scientific knowledge of smog to catch up with our allergies to it.

It wasn’t called smog then. The Los Angeles Times once called it “daylight dim out.” But the term “smog” eventually entered the popular vernacular – mixing the words smoke and fog.

Futile attempts

Shutting down a plant that was blamed for the unprecedented smog didn’t help, writes McNally, and the problem just got worse. It wasn’t until the early 1950s that it became clear that the exhaust from the cars everyone was using to get around was causing most of the smog.

The mayor of L.A. vowed, futilely, to get rid of the smog within four months. Still, it lingered. And nine years later, California got scared straight by the deaths of thousands of Londoners in a historic 1952 smog incident

California’s then-governor hired a guy to make recommendations about pollution reforms. The Beckman Commission recommended car exhaust standards, banning open burning of trash, more controls on refineries and fueling operations, slower growth for heavy polluting industries, and a mass transit system. The recommendations of Arnold Beckman, founder of Beckman Instruments, would serve as a road map for what air regulators have been doing ever since.

The efforts toward smog controls in California spurred the national conversation and the Clean Air Act in 1970. The state has now a whole plan – as every state now does – for how to meet a raft of air pollution standards. So does each region in California, including the South Coast Air Quality Management District. We measure ozone – that basis for smog – over an hour, and eight hours. We measure chemicals in air, including carbon monoxide, sulfur dioxide, nitrogen dioxide. We measure lead. We even measure the particulates in multiple sizes.   

Little improvement

This 1943 so-called “hellish cloud” was the most vivid warning of LA’s smog problems to come. Smog in fact continued to blanket the city in the 1950s. Lee Begovich, who moved to the city in 1953, told the Washington Post she was stunned when wind blew the smog away one day and she finally, for the first time, saw the San Gabriel Mountains to the northeast. In 1954, Getty wrote that there were so many red eyes, one person said “you couldn’t tell the people with hangovers from those who went to bed the night before”.

People wore masks to counter what the Washington Post described as “eye-burning, lung-stinging, headache-inducing smog”. In 1958, the city even set up a smog relief team to provide residents with “fresh air” brought from outside of Los Angeles. Whether it was effective is unclear. 

Mask-wearing guests at a banquet

Smog continued to cover the city as Los Angeles expanded, which meant more factories and highways. The city did have Air Pollution Control, an early pollution monitoring group. 

Continuing into the 1960s, parts of Los Angeles were getting 200 smoggy days each year. When the Clean Air Act was passed in 1970, Congress approved an amendment that allowed California to incorporate harsher pollution controls than the rest of the country. It had to deal with the problem. Even if the change wasn’t sudden, the air quality in Los Angeles slowly improved, and that was largely due to the Clean Air Act, which helped lower emissions from cars and industry.

Is clean air within sight?

The city’s air quality future is far from clear. President Donald Trump has said he’ll revoke the state’s ability to set auto-emission standards, which could mean more smog. California and 22 other states are suing the administration to keep that from happening. Also, warmer climates mean ozone forms quicker and is harder to control. While LA doesn’t look as bad as it did before the Clean Air Act, it still gets smoggy days.

In 2020, the city has a population of 4 million people, but 8 million cars: something to think about.



Read the full articles and more here:

  1. Molly Peterson, July 2013, 70 years later, remembering the day the smog blocked out the sky (
  2. South Coast AQMD, May 1997, The Southland’s War on Smog: Fifty Years of Progress Toward Clean Air (through May 1997 (
  1. Jess McNally, July 2010, July 26, 1943: L.A. Gets First Big Smog (
  2. Kat Eschner, July 2017, This 1943 “Hellish Cloud” Was the Most Vivid Warning of LA’s Smog Problems to Come (
  1. James Pasley, January 2020, 35 vintage photos reveal what Los Angeles looked like before the US regulated pollution (