Water and Power Associates Informing the Public about Critical Water and Energy Issues facing Los Angeles and California

Historical Notes

By the late 1940s, smog in Los Angeles had reached crisis levels. Millions of cars were on the road, and the region’s perfect storm of geography, industrial growth, and temperature inversion created ideal conditions for trapping photochemical smog. The Civic Center, as seen here, was often cloaked in thick haze—visibility dropped, and respiratory irritation became part of daily life.

Historical Notes

Los Angeles experienced smog well before the postwar population boom. As early as 1903, smoke and industrial fumes were so dense that residents mistook a midday event for an eclipse. Between 1905 and 1912, the City Council passed several early anti-smoke ordinances, but they were no match for the massive urban and industrial expansion that followed. By the 1940s, downtown streets like 1st and Broadway often sat beneath a gray-brown canopy of pollutants.

Historical Notes

From the observation deck of City Hall, landmarks such as the State Building and the L.A. Times Building were often obscured by thick smog during the early 1950s. Visibility across downtown could disappear within a few blocks—yet this was considered a normal part of life in mid-century Los Angeles.

Historical Notes

A smoggy morning view south along Hill Street captures the extent of the haze blanketing Los Angeles in the late 1940s. The original caption from the Examiner read “Beautiful Los Angeles Smog,” a tongue-in-cheek nod to the city’s worsening air quality. Two years earlier, in 1947, Los Angeles County established the nation’s first air pollution control program—the Los Angeles County Air Pollution Control District.

Historical Notes

Before any meaningful emissions regulations, scenes like this were common across Los Angeles. Cars belched visible smoke, and there were no smog checks to limit pollution. California wouldn’t launch its first vehicle emissions testing program until 1984, decades after photos like this made the problem painfully obvious.

Historical Notes

During the 1940s, Los Angeles saw a massive influx of wartime workers and new residents, turning it into the largest car market in the world. With little mass transit expansion and sprawling suburbs, the city’s auto-centered growth quickly overwhelmed its infrastructure—and its air. The basin’s geography only made things worse, trapping exhaust and industrial emissions in a bowl of stagnant air.

Historical Notes

After one of the first major smog events in 1943, city officials wrongly blamed the Southern California Gas Company’s Aliso Street plant, which was producing butadiene, a chemical used in synthetic rubber. Although the plant was temporarily shut down due to public pressure, the smog only worsened. Mayor Fletcher Bowron declared the problem would be solved within four months—an optimistic prediction that proved far from accurate.

Historical Notes

This photo, taken at 1st and Olive Streets, shows buildings nearly disappearing into a wall of smog. In the early 1950s, Caltech chemist Arie Haagen-Smit solved the mystery of L.A.'s smog by identifying ozone as its main component. He demonstrated that ozone formed when sunlight interacted with unburned car exhaust and hydrocarbons from refineries. His research explained not only the hazy skies, but also the bleach-like odor, eye irritation, and health issues plaguing the city.

Historical Notes

From the site of the Santa Ana Freeway construction, this view southwest toward City Hall shows downtown in transition—both physically and environmentally. Despite freeway expansion promising greater mobility, it also meant more cars, more emissions, and worsening smog in the city’s core.

Historical Notes

On September 9, 1954, a Navy blimp hovered over downtown Los Angeles to collect air samples at multiple altitudes—500 feet, 1,000 feet, and the top of the smog layer. The mission was part of early scientific efforts to better understand what made L.A.’s air so hazardous, and to support the work of researchers like Haagen-Smit in identifying smog’s chemical composition.

Historical Notes

By the mid-1950s, the health effects of L.A.'s smog were impossible to ignore. On bad days, children stayed home from school, athletes avoided outdoor practice, and crops suffered visible damage. Hospitals saw surges in patients with headaches, irritated eyes, and difficulty breathing. In this photo, the visibility is so poor that City Hall can barely be seen through the haze.

Historical Notes

Even law enforcement wasn’t spared the effects of L.A.'s eye-stinging air. This 1955 image of an LAPD officer squinting through the haze captures the day-to-day human toll of smog—something Angelenos endured for decades without relief.

Historical Notes

From atop Angels Flight, the historic funicular on Bunker Hill, the view of the city should have been sweeping. Instead, this 1958 image—published by the L.A. Times—shows buildings nearly lost in the thick smog that regularly obscured the city’s skyline.

Historical Notes

Before curbside trash pickup and centralized waste management, Angelenos burned much of their household waste in backyard incinerators. This oversized unit on Bunker Hill, with City Hall in the background, reflects how common open burning was—and how it contributed significantly to the city’s worsening air pollution.

Historical Notes

Backyard incinerators like this one were used daily across Los Angeles neighborhoods. Although they were convenient for waste disposal, they sent smoke and ash into the air—adding to the already dangerous mix of vehicle and industrial emissions.

Historical Notes

By the mid-1950s, nearly every home had a backyard incinerator. That changed on October 1, 1957, when the Air Pollution Control District’s ban on residential trash burning took effect. It was a major step forward in reducing air pollution and one of the first public policy victories in L.A.'s long battle against smog.

Historical Notes

In addition to incinerators, Los Angeles' severe smog problem in the early 1950s was caused by several factors: rapid population growth and industrialization after World War II, a doubling of automobiles between 1940 and 1950, geographic and weather conditions that trapped pollutants, and the lack of emissions controls on vehicles and industries.

Historical Notes

By the mid 1950s there was no doubt among scientists that cars were a primary factor in LA’s smog crisis.
However, Los Angeles had no influence over the auto manufacturers. Smog wasn’t yet a national problem and it was very easy to dismiss smog as a quirk of LA geography.

Automakers were slow to respond.  They were wary of any change that would add cost to their vehicles.  As a result of public pressure, emission regulations would come to pass.  But, it would take another two decades for things to change.

It wasn’t until 1975 that the U.S. required new cars to have catalytic converters, the key piece of technology that allowed everything to change. ^

Historical Notes

Air pollution reached its worst levels in Los Angeles during the 1940s and 1950s. Millions of people driving millions of cars plus temperature inversion provided Los Angeles with a near perfect environment for the production and containment of photochemical smog.

Historical Notes

On August 22, 1964, Los Angeles basin was recognized as having the worst ozone problem of any city in the U.S.*

Historical Notes

Photo caption for the above photo reads: “SMOGGY DAY-It was smoggy yesterday as indicated by this photograph made from Figueroa St. looking east on 6th St. But it wasn't nearly as bad as the Air Pollution Control District predicted.”

Historical Notes

It wasn’t until 1975 that the U.S. required new cars to have catalytic converters, the key piece of technology that allowed everything to change.

The introduction of catalytic converters drastically reduced tailpipe emission pollutants. Hydrocarbon and nitrogen oxide emissions from new cars plummeted from an average of 14 grams per mile in 1965 to just 3 grams per mile by 1975.

This dramatic reduction in vehicle emissions was a major factor in the gradual improvement of air quality in the LA basin over subsequent decades.

Historical Notes

In the 1970s and 1980s formal Smog Alerts were issued asking people to reduce driving.  Schools were also affected by Smog Alerts.  If the alert was bad enough, recess was cancelled and children were kept inside to play board games.  Unfortunately, classrooms didn’t have air conditioning or filters so being inside wasn’t much better than being outside.

Smog Alerts came in three stages:  Stage 1 – Unhealthy; Stage 2 – Very Unhealthy; Stage 3 – Hazardous

Historical Notes

In 1984, The California Smog Check program went into effect to identify vehicles in need of maintenance and to assure the effectiveness of their emissions-control systems.*

Historical Notes

In 1974, the nation’s last recorded Stage Three smog alert occured in Upland (east of Los Angeles). Ozone levels hit .51 parts per million. Gov. Ronald Reagan urged residents to “limit all but absolutely necessary auto travel” and recommended that people drive slower to reduce emissions.*

Historical Notes

In 1987, AQMD established a landmark rideshare program requiring companies employing at least 100 people to offer incentives to workers to carpool or use public transit. Employers complained that it shouldn’t be their job to change workers’ driving behavior, and the project went away in a few years.

Historical Notes

Most of smog found in Los Angeles is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog.

Historical Notes

In 1993, bowing to pressure to do its part to revive the sluggish economy, the AQMD approved a program that allowed major polluters to trade emission credits among themselves. The program, dubbed RECLAIM, proved ineffective and fed the agency’s soft-on-the-bad-guys reputation that continues to this day.

Some 58 bills were introduced in Sacramento that would exert control over the AQMD and state Air Resources Board and make them more business-friendly. *

Historical Notes

IIn 1996, the ‘Big Seven’ automakers committed to make zero-emissions vehicles, and General Motors rolled out the EV-1.

Historical Notes

In 2003, automakers went to court and effectively eliminate the state’s zero-emissions vehicle standards.

Historical Notes

The year 2000 saw a milestone in that no Stage One smog alerts were issued for that year, compared to 42 days in 1990, when people with respiratory problems were urged to stay indoors.

Historical Notes

Although a pristine view of the downtown skyline may still elude Angelenos on most days, air pollution rarely cripples the city in present times as it did in the mid-twentieth century. Severe smog has largely abated.  This was all due to citizen activism, scientific advances, and landmark environmental legislation that allowed the EPA to regulate air pollutants.

Historical Notes

In the 1970s and '80s, the Los Angeles region often saw more than 200 bad-air days a year, with ozone levels exceeding 300 parts per billion on the smoggiest summer days. Peak ozone concentrations have dropped to about a third of that, even as the region’s population has grown and the number of vehicle miles traveled has doubled.

The success of emissions standards that began more than four decades ago, especially The Clean Air Acts of 1970 and 1977, has slashed air pollution in Southern California by 70% since 1970.

Historical Notes

Over the past several decades, California officials set groundbreaking standards that phased out many inefficient car and truck engines and some of the dirtiest fuels for everything from jet skis and lawnmowers to school buses and heavy-duty trucks. Local smog-fighters in the Los Angeles basin forced cleanup of oil refineries, manufacturing plants, and consumer products such as paints and solvents. Other local and state programs offered incentives for replacing old trucks and buses.

The result: Some of the most problematic pollutants-smog-forming nitrogen dioxide and fine particles created by diesel-engine exhaust and other fossil fuels-declined in the worst neighborhoods by up to 50 percent in 20 years.^*

Much more can still be done.

HistoricalNotes

In the 1955 view looking east on 1st Street at Olive, dense smog hangs over the Civic Center, partially obscuring City Hall and other public buildings. The murky skies were typical of mid-century Los Angeles, when air quality reached crisis levels due to unchecked vehicle emissions and industrial pollutants. This image also captures a moment just before downtown’s topography was dramatically reshaped. Bunker Hill, once a steep and elevated residential area, was literally shaved down—flattened by more than 30 feet in some areas—as part of the city’s massive redevelopment effort beginning in the 1950s. By 2016, the same view reveals a radically altered streetscape and a striking improvement in air quality, a result of decades of regulatory progress, including the introduction of catalytic converters, emissions testing, and the founding of the South Coast Air Quality Management District (AQMD). The difference between the two photos is not just visual—it's environmental, political, and architectural.

Historical Notes

This 1959 view looking south on Broadway from 1st Street captures a city amid transformation. In the foreground, traffic fills the street under a layer of smog typical of the era, while overhead wires for streetcars—already in decline—still hang above. Though City Hall isn’t visible in this frame, it’s nearby, just east of the intersection. The surrounding buildings reflect a low-rise, pre-redevelopment downtown, with a mix of early 20th-century commercial structures that would soon be overshadowed—both physically and culturally—by larger civic and cultural projects. By 2022, this corridor had been fully reimagined. Streetcars had vanished, sidewalks had been widened, and nearby landmarks like Grand Park, the Broad Museum, and updated government buildings helped define a more pedestrian-friendly civic core. The most noticeable difference may be the air itself—clear and bright, in contrast to the haze that once regularly blanketed the heart of Los Angeles.

Historical Notes

In this 1950s photograph looking west through the 2nd Street Tunnel from Hill Street, a line of automobiles inches out of the portal, caught in the slow churn of downtown traffic beneath a blanket of smog. Perched above the tunnel are the rooftops of Bunker Hill’s once-grand Victorian homes and mid-rise apartment buildings—remnants of a neighborhood already in decline and on the brink of erasure. A small parking lot atop the slope reflects the postwar shift toward car-centric planning, even in the city’s core. By the 2020s, nearly every building in the old scene had been demolished and replaced as part of the Bunker Hill Redevelopment Project. The modern view reveals a dramatically altered skyline featuring The Grand LA by Frank Gehry and the Conrad Los Angeles Hotel, completed in 2022. Although the tunnel itself remains, it now frames a thoroughly transformed Los Angeles—clearer, taller, and reshaped by 70 years of planning, ambition, and environmental reform.

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