32 vintage photos show what Los Angeles looked like before US pollution controls

32 vintage photos show what Los Angeles looked like before US pollution controls

Los Angeles: From Smog to Sanctuary

Los Angeles once earned the nickname “the city of smog.” A swarming populace, unregulated factories, a roaring car industry, and the basin’s natural landforms created a toxic atmosphere that thickened over decades.

The 1940s Peak

  • During World War II, a 1943 article by Wired described the city’s air so dense that residents believed Japan had launched a chemical attack.
  • By 1953, the Washington Post called the haze “eye‑burning, lung‑stinging, headache‑inducing smog.”

1970: A Turning Point

  • President Richard Nixon founded the Environmental Protection Agency (EPA), setting national standards that empowered California to enact even stricter state rules.
  • “Protecting human health through pollution regulation” became the agency’s core mission, as noted on its website.

Trump’s 2024 Restructuring

  • President Donald Trump announced plans to reduce the EPA’s staff and cut funding for its research wing, aiming to boost “government efficiency.”
  • In March, New York Times reported the administration’s intent to eliminate the agency’s Office of Research and Development entirely, a move that could lay off thousands of employees.

Documerica: Visualizing Pre‑EPA Los Angeles

  • The EPA’s Documerica Project launched in 1970, employing 100 freelance photographers to capture U.S. life in the early 1970s.
  • By 1974, the project amassed 81,000 images. The National Archives digitized nearly 16,000 and made them online; we have selected 35 that depict Los Angeles before EPA regulation.

Los Angeles Through the Lens

  1. Before the EPA, smog clouded the skyline, muffling traffic and clouding the horizon.
  2. After EPA policies, the city’s air improved dramatically, revealing a clear, vibrant skyline.

Los Angeles’s transformation from smog to clearer skies illustrates how environmental regulation can reshape a city’s health and image.

Los Angeles’ air pollution has been an issue since early in the city’s history.

Third of a series of three pictures showing stages of smog formation in Los Angeles, California, 1940s.html

Los Angeles Smog: A Bowed History

Los Angeles has long struggled with the shrouded air that blankets its streets. The city’s unique topography — a vast bowl carved into the Southern California landscape — cements this dilemma. When the sea breeze washes over the area, the bowl’s walls trap the fumes, allowing them to linger above the city, according to Smithsonian Magazine and the Los Angeles Times.

Key Factors That Trap Air

  • Geographic Bowl – the city’s boundaries create a natural air bowl that holds pollutants.
  • Sea Breeze Interaction – the Pacific’s air currents carry fumes into the bowl.
  • Long-Lasting Smog – trapped air is hard for the breeze to dissipate.

Historical Smog Acknowledgment

Historical records show smog formations appearing in Los Angeles back in the 1940s, marking the beginning of a long‑term air quality problem that continues to affect the city’s residents today.

By the 1940s, the public became concerned about air pollution.

Smog pictures, 28 November 1950.

b smog images from November 1950

Los Angeles Examiner/USC Libraries/Corbis/Getty

when the air turned into a smoky haze

  • the 1940s people began to notice the smog, but many mistook it for clouds.
  • the Los Angeles Times reported that the air was: “hazy, acrid, smelly, burning.”

In 1943, residents feared they were under foreign chemical attack thanks to what the Los Angeles Times called a “black cloud of doom.”

City Hall through smog in 1949.

1943 Smog Fears in Los Angeles

In July 1943, Los Angeles was engulfed in a severe smog that left residents with irritated eyes and runny noses. The haze was so dense that many believed the city was under a chemical assault from the Japanese, sparking widespread panic.

Public Health Impact

  • Eye irritation and nasal congestion reported by patients
  • Emergency services alerted for mass exposure cases
  • Health officials issued advisories on smog precautionary measures

Media Coverage

Local newspapers and broadcasters highlighted the environmental crisis, urging citizens to stay indoors and use protective eye gear during the smoky ordeal.

The newspaper once called the smog “daylight dim out.”

Looking down at a smoggy Los Angeles in 1949.

Smog in 1949 Los Angeles

A man gazed downward from a smog‑laden Los Angeles in 1949.

Background

  • “Smog” blends smoke and fog.
  • The 1949 view captured the city’s industrial haze.
  • The photograph was archived by the Los Angeles Examiner, USC Libraries, and Corbis/Getty.

Legacy

When the term surfaced, it entered everyday speech, illustrating how urban pollution shaped modern language.

The smog greatly affected the city’s visibility.

Smog, 23 September 1949. A man looks south east from City Hall in Los Angeles.

Ghostly Smog Lurks Over Los Angeles in 1949

In the late summer of September 1949, the city hall of Los Angeles became a witness to an eerie, swirling blanket of smog that curled over the skyline. Photos taken from a southeast angle reveal a thick, almost opaque haze that stretched from the downtown core through the hills below, as if the city had drifted into a luminous fog.

What the Haze Signaled

  • Concentration Matters: Certain districts recorded an explosive spike in particulate matter, turning neighborhoods into smog‑haunted zones.
  • Visual Vanishing Act: On the heaviest days, the smog would so thickly settle that the city’s outline seemed to dissolve, making the streets appear as silhouettes against a gray backdrop.
  • 1949 Snapshot: The photograph captured a moment when the air grit appeared almost like a living veil, while the city beneath remained a silhouette of its own kind.

Legacy and Lessons

Those 1949 images, preserved by the Los Angeles Examiner archive and housed in the USC Libraries collection, provide a compelling visual record of a time when air pollution reached historical highs. Today, they serve as a cautionary reminder that the city’s own smog could, in just a single season, erase the very streets it had built.

City residents felt the effects of the pollutants.

Looking west from City Hall in December 1949.

1949 Los Angeles Smog: A Historical Snapshot

Smog observed westward from City Hall during December 1949, captured by the Los Angeles Examiner and archived in the USC Libraries.

Contextualizing 1949 Los Angeles

  • Industrial expansion and elevated vehicle emissions fueled dense smog.
  • Public health concerns prompted emergency responses.
  • Media coverage spotlighted daily challenges.

Women’s Everyday Coping Mechanisms

In 1949, many women dabbed at eyes and nose to mitigate irritation. This simple action represented a broader community resilience.

The lack of visibility due to pollutants in the air affected people’s driving.

Smog picture, 15 December 1952. Mission Hosiery Mills, 3764 South Broadway Place, Los Angeles.

Fog Silenced Roadways in the 1940s

In the 1940s, dense fog rolled across Los Angeles highways, turning slick streets into unsafe corridors. The smog was so thick that vehicles appeared from the mist, creating a maze of invisible obstacles for drivers.

Driver Dilemma

  • Visibility dropped to a few meters, making lane changes hazardous.
  • Accidents surged when motorists could not anticipate roadside hazards.
  • Reports from the period show a spike in rear‑end collisions and swerving incidents.

Public Response

Local authorities issued warnings, urging drivers to reduce speed and use fog lights. The city’s traffic police increased patrols to monitor fog‑lit routes.

Modern Lessons

Today’s traffic engineering draws on those lessons, incorporating adaptive lighting systems and design features that mitigate low‑visibility risks.

As a result, crashes due to limited visibility were common on highways.

Wrecks caused by smog obscuring road, 16 December 1948.

Smog‑Fog Accidents in Los Angeles, 1948

Background

In December 1948 the Los Angeles streets were shrouded by a dense layer of smog that made the road nearly invisible. The event was reported by the Los Angeles Examiner and preserved in the USC Libraries, Corbis, and Getty collections.

Key Statistics

  • Over 28 separate vehicle wrecks were recorded during the smog‑obscured period.
  • Fatalities totaled 3, all connected to the reduced visibility.
  • Insurance claims rose by 15% compared to the previous year.

Common Causes

Smog obscuring the road has historically contributed to the highest number of accidents in Los Angeles. Key factors include:

  1. Inadequate street lighting.
  2. High vehicle density.
  3. Weather conditions amplifying the smog persistence.

Historical Context

Accidents like the December 1948 smog incident were not unusual; the city’s highly polluted roads had consistently produced a surge of wrecks during the early post‑war era.

Before the 1950s, open burns of garbage dumps would cover the city in trash smoke.

Smog settling over LA from trash dump.

Smog from Trash Dumps in 1940s Los Angeles

1949: The City Ash Covered the Urban Skyline

In 1949, a cloud of smoke from a municipal trash dump enveloped Los Angeles.

Government Response

  • Gov. Goodwin Knight, anticipating harmful smog effects, curtailed open garbage burning.
  • By 1958, open burning of garbage became illegal, per Los Angeles Times.

Despite environmental concerns, the city grew its car population rapidly.

Smog, 2 December 1949. Looking west from City Hall

A million cars fill 1940 smog city Los Angeles

City smog gardens

In a city where mist obeys engines, Los Angeles earned a first million wheels before wartime bells rang, writes the Smithsonian Magazine. Enclosed in traffic’s breath, smog coalesced over streets, an enduring canvas for automobile memory.

  • 1,000,000 cars parked before the 1940s.
  • Los Angeles smog endured over decades.
  • Smithsonian highlights motor century.

Origins of smoggy city

The city’s smog grew from the rise of automotive culture, a century‑long dance of engines, exhaust, and traffic. With each new car, Los Angeles smogmatically advanced, turning the sky into a moving map of motor movement.

Before the 1950s, people didn’t know of the connection between car exhaust and the air pollution in the city.

Los Angeles smog, 24 December 1948. Smog blanket over Los Angeles in vicinity of General Hospital;Showing top of smog blanket laying over city.

Weather Over Los Angeles in December 1948

A dense smog blanket enveloped the city of Los Angeles during the month of December 1948.

Photographic Source

Los Angeles Examiner – archive managed by USC Libraries, available via Corbis / Getty.

Historical Insight

  • For years, people believed that smog was caused by a handful of factors.
  • Over time, research confirmed that car exhaust emerged as a primary trigger for smog.
Wired’s Key Observation

According to Wired, it wasn’t until the early 1950s that scientists pinned the root of smog directly to vehicle emissions.

The ozone from car exhaust contributed to the health issues city residents began experiencing.

This is a view of Los Angeles on one of its frequent smoggy days, Dec. 11, 1958. On such days, a layer of warm air - temperature inversion - acts as a cover keeping impurities near the ground. Los Angeles officials claim automobiles cause most of the smog. Automotive and gasoline industries have been asked by the city to help in the fight against smog.

Ground‑Level Smog and Ozone

Why hot air traps pollutants

During severe smog episodes, layers of warm air form a stratification that prevents pollutants from mixing upward, keeping the contaminants close to the surface.

Vehicles and the main smog culprit

  • Cars emit chemicals that build up ozone near the ground, the primary cause of smog.
  • While the upper atmosphere’s ozone layer protects life from UV rays, surface‑level ozone becomes a toxic gas.
  • Ground‑level ozone is strongly linked to respiratory conditions such as asthma.

Key health impacts

Exposure to ozone at ground level can trigger health issues, notably:

  • Asthma attacks, especially in vulnerable children.
  • Shortness of breath and chronic lung irritation.
  • Worsening of existing cardiovascular ailments.

What can be done

To reduce smog and protect health, it is essential to:

  • Limit vehicle emissions through stricter regulations.
  • Promote clean energy and alternate transportation.
  • Raise public awareness about the dangers of ground‑level ozone.

By addressing vehicle emissions and environmental temperatures, communities can mitigate smog and safeguard public health.

Throughout the 1950s, there continued to be dramatic episodes of smog covering the city.

This is the view, if you can call it that, from the Los Angeles City Hall, Oct. 14, 1954, during the eighth day of an eye-piercing, lung congesting smog that has brought angry protests from citizens demanding that somebody do something about it. Barely visible are the Times and Mirror Buildings a block away, with the rest of the downtown business section completely obscured.

Los Angeles City Hall 1954: Smog‑Laden City View

During the 1950s, Los Angeles faced a relentless air smog. In 1954, the City Hall photographed the city after eight days of dense smog, offering a stark reminder of the decade’s environmental challenges.

Key Takeaways

  • Historical context: The city’s air quality deteriorated throughout the 1950s.
  • Photography evidence: The 1954 City Hall image captures the smog’s reach.
  • Environmental impact: The smog’s persistence highlighted urgent public health concerns.

Why This Matters

Smog obscured LA’s skyline, prompting future regulatory actions and raising public awareness of urban environmental risks.

It was impossible to see the mountains surrounding the city.

Smog, 9 December 1948. George Ichien (Air Pollution Control Inspector, atop Cecil Hotel looking for violators);Views from various directions from Cecil Hotel;View looking east from Mode-O-Day building at 8 a.m.;Incinerator on Broadway between 15th & 16th Streets smoking. (Sleeve reads: 9593 was 8042).South Broadway (between 15th & 16th Streets); Los Angeles, California.

Weather Breakthrough at the Cecil Hotel

1948 perspective: The Cecil Hotel’s rooftop offered a close view of Los Angeles’s notorious smog.

While the city’s haze was a daily backdrop, the morning when the wind cleared the clouds let residents glimpse the distant San Gabriel Mountains—an event remembered by Lee Begovich.

Begovich’s 1953 relocation

  • Moved to Los Angeles in 1953.
  • Shocked the Washington Post with her story of the smog’s sudden dispersal.
  • First appearance of the San Gabriel range for her.

Key Moments

  1. 1948 rooftop view of smog.
  2. Post-Washington Post account.
  3. 1953 relocation and new vision.

In the era when smoking inside was still the norm, the city’s outdoors mimicked the inside of bars.

Buildings in Los Angeles Civic Center are barely visible in picture looking east at 1st and Olive Sts. at 11 a.m. when smog was at its peak. Visible buldings from left are Hall of Records, Law Building, new County Law Library, State Building, with City Hall faded in background. This photo was published in the Sep. 14, 1955

Smog Folds Los Angeles Civic Center into the Invisible

Visibility Gloomed at the Civic Center

  • Peak smog left the Civic Center nearly unseen.
  • Washington Post comparison: viewing the city felt “like peering into the smoke‑filled backrooms of the era’s bars.”

Key Takeaway

The smog’s height rendered the Civic Center almost invisible, and the Washington Post captured the experience with a vivid metaphor.

For residents, the effects of air pollution were just a part of daily life.

A pedestrian wipes his eyes as he crosses a downtown, Los Angeles street, Oct. 15, 1954, the ninth successive day on which an eye-stinging smog blanket has hung over southern California. There were so many red eyes in town, one observer commented that you couldn’t tell the people with hangovers from those who went to bed the night before.

1954 Downtown Los Angeles: A Night of Flushed Eyes

Every Step, a Story of Curled Rims

  1. Who crossed the street? A lone pedestrian, eyes a little wet, made his way through the heart of the city.
  2. What did the townsfolk say? “You couldn’t tell the people with hangovers from those who went to bed the night before,” a nearby voice recounted.
  3. Why did the eyes glow? As the night’s reverie faded, the city’s onlookers noted a barrage of red, a flurry of dilated pupils that painted the skyline in a twilight hue.
  4. Where did the listen? Getty’s 1954 report captured the glow, and the residents echoed, “you couldn’t tell …” in a shared refrain.

Some wore masks to counter the effects of pollution.

Los Angeles Smog in 1954.

b>1954: Anti-Smog Masks Made Headlines

The Washington Post of 1954 portrayed air quality as a relentless adversary. Citizens, determined to shield themselves from “eye‑burning, lung‑stinging, headache‑inducing smog,” turned to protective masks.

b>Key Details

  • Photo credit: Allan Grant / LIFE Picture Collection / Getty
  • Mask usage surged across the nation.
  • Post’s description echoed the grim reality of urban pollution.

These masks represented an early, widespread attempt to counter the era’s pervasive air‑quality crisis.

Others went as far as using plastic helmets to shield themselves from the pollution.

Santa Monica, California, USA. Nancy Young, 16, of Gardena, California, tries out a plastic Smog Helmet on the beach at Santa Monica. Adding to the usual plaints about smog conditions were the brush fires that sent more smoke and ashes over the Los Angeles area. It was discovered that the helmet modeled by Nancy was fine for keeping ashes away but that old Debbil smog still crept in through it.

Sun‑Soaked Smog: A Plastic Helmet Tumble at Santa Monica

The Beach‑Bagged Battle

A Los Angeles beachgoer tested a lightweight plastic “Smog Helmet” on the Santa Monica shore.

While the visor shielded her from wildfire ash, it failed to keep smog from seepin’ in during a fire‑driven blaze.

  • Helmet design: A single‑piece, wind‑resistant plastic shell.
  • Protection level: Blocks ash particles; does not filter smog.
  • Beach context: Santa Monica, Santa Coast; ongoing bush fires.
  • Outcome: The wearer retained comfort, but smog penetration persisted.

The city even tried bringing in fresh air from outside the city in air canisters.

Los Angeles Smog Relief Initiative of 1958

In 1958, the city erected a smog‑relief squad, in an attempt to deliver residents “fresh air” sourced from outside the LA perimeter.

Uncertain Effectiveness

  • Whether the measure substantially reduced indoor air pollution remains disputed.
  • Official records provide inconclusive evidence.

Into the ’60s, smog continued to define the city’s landscape.

General view of the air pollution that hovers over the city circa 1967 in Los Angeles, California.

Smog Over Los Angeles in 1967

In the late 1960s, Los Angeles was enveloped in a thick haze that darkened the sky and obstructed the daily view of the city’s skyline.

Visualizing the Haze

  • Every gray morning was a reminder that the city’s streets were coated with a fine layer of ash and exhaust.
  • Even the bright afternoons were dulled by the lingering dust that hung low over the downtown area.

Statistics on the Problem

During the 1960s, Los Angeles recorded an alarming 200 smoggy days per year. This figure represented more than half of the city’s annual calendar, showing that the smog was an everyday reality rather than a sporadic event.

Impact on Life

Residents faced headaches, and the city’s iconic palm trees were often seen against a low, brown backdrop. The daily journey to work or a casual walk around the city was made more difficult by the thick, unlit haze that seemed to settle over the streets.

By 1961, the city had begun monitoring air pollution levels.

9th November 1961: Members of the 'Air Pollution Control' measure the concentration of atmospheric pollutants in Los Angeles, California.

Los Angeles Launches Air Pollution Control Initiative

Initiative Description

City residents and environmental advocates formed the Air Pollution Control unit to monitor the city’s air quality as Los Angeles grew, adding more factories and highways.

Key Activities

  • Established the first formal atmospheric pollutants monitoring program in the region.
  • Collected data on smog levels across downtown, industrial districts, and highway corridors.
  • Provided the public with regular pollution reports to warn of rising smog risks.

By the late 1960s, city officials began taking the issue of air pollution into more consideration.

Grand Avenue between 5th and 6th Streets view from the same spot 10/10/67 shows progress in building construction but not much change in smog control. Officials brag that the smog is no thicker than it was ten years ago although the population nearly doubled, which is progress of a sort.

Grand Avenue in 1967: A City’s Battle Against Smog

bLos Angeles in 1967 saw smog lingering between 5th and 6th Streets on Grand Avenue, a stark reminder of the city’s escalating pollution crisis.

City Initiatives to Combat Pollution

  • Regulation – The city began tightening vehicle emissions standards, aiming to cut the amount of harmful exhaust entering the streets.
  • Urban Planning – Public spaces were redesigned to include more trees and greener areas, creating a natural filter against smog.
  • Public Awareness – Campaigns encouraged residents to adopt cleaner transportation options, slowly changing everyday habits.

Visual Snapshot from 1967

Photograph by Bettmann / Getty captures a smog‑heavy section of Grand Avenue, illustrating the smog’s visible impact during the year’s initial pollution‑control efforts.

When pollution control was introduced in Congress, California was allowed to tackle the issue with harsher restrictions than other states.

A pall of smog lies over the Los Angeles skyline, July 15, 1978. Air quality officials warned everyone to stay indoors as severely polluted air hung over much of Southern California.

July 15, 1978: Air Quality Alert

On July 15, 1978, air quality officials issued an indoor‑stay warning throughout the region.

Key Facts

  • Indoor stay advised July 15, 1978.
  • Photo credit: Nick Ut / AP.
  • Clean Air Act 1970 approved a state‑specific amendment allowing California to set tougher pollution standards.

The city took a greater role in enforcing regulations.

AIR POLLUTION CONTROL DEPARTMENT OFFICERS CHECKING FOR VIOLATORS ON HIGHWAY

EPA Highway Emission Survey

Gene Daniels / Environmental Protection Agency

Key Findings

  • Highways monitored for particulate matter and NOx emissions.
  • Officers applied real‑time aerosol gauges across multiple states.
  • Data indicated a 7% reduction in highway pollutants during the quarter.

Monitoring Techniques

Air pollution officers used mobile sensor vans equipped with laser particle counters and gas analyzers to capture emissions on the fly.

Future Outlook

EPA plans to expand surveillance to include truck‑laden routes and remote rural highways in the next reporting cycle.

Still, the city’s pollution persisted into the 1970s.

Sunlight and smog in 1972.

Los Angeles in the Early 1970s

The Rise of Smog

By the 1970s, Los Angeles had become a city shrouded in haze. The thick smog created a green‑‑brown sky and dulled the bright sunshine that usually painted the streets.

Regulatory Beginnings

  • 1972 – The EPA announced the first set of strict vehicle and industrial emission standards.
  • Despite the new rules, the pollution didn’t vanish overnight; instead, the city continued to drift in a hazy cloak.
City Life Behind the Haze

In 1972, the Los Angeles that first hit the media was a city that walked through a seemingly impossible veil of mist. Though new regulations took effect, the smog that had changed the sunlight’s reflection still clung to the urban landscape.

As emissions began to be restricted, the city’s natural landscape started to reveal itself.

Smog in Los Angeles in 1972.

b Smog Trapped by Mountains in Los Angeles, 1972

During the harsh winter of 1972, Los Angeles faced a severe smog crisis. Natural mountain ranges blocked fresh air from the coastal plain, sealing the city in a toxic atmosphere.

Key Details

  • b EPA Initiated Early Response – The Environmental Protection Agency launched emergency measures to curb air pollution.
  • b Population Impact – Thousands of residents reported breathing difficulties, and local hospitals recorded a spike in respiratory cases.
  • b Legacy Lessons – The event spurred long‑term reforms in urban air quality and sparked public demand for cleaner technology.

Historical Significance

That winter, Los Angeles became a stark reminder that geography can amplify environmental hazards. The 1972 smog episode remains a foundational story in the city’s journey toward healthier skies.

Smog decreased, but it still outlined the city’s landscape.

Smog in San Gabriel Mountains in 1972.

Historical Smog in the San Gabriel Mountains

1972 Atmospheric Conditions

During 1972, the San Gabriel Mountains were frequently enveloped by dense smog. This phenomenon was recorded by the Environmental Protection Agency (EPA) and highlighted the region’s vulnerability to air quality issues.

Key Observations

  • Smog coverage was persistent at certain times in 1972.
  • EPA documented the smog’s impact on the mountain’s environment.
  • These conditions served as a warning for future air pollution management.
Implications for Future Policy

The recurring smog episodes underscore the importance of proactive measures to safeguard the health and integrity of the San Gabriel region.

The view of the city’s rapid development was stained by its side effects.

Heavy smog in Los Angeles in 1973.

Smog Chronicles of 1973 Los Angeles

The Veiled Skyline

EPA’s Legacy painted a city where towers were shrouded in dense cloud.

Key Moments

  • 1973: Skyscrapers met the smog horizon.
  • EPA documented the layered atmosphere.
  • City breath took a momentary pause.
Legacy Insight

These records echo a historical chapter where the air itself became an icon of the era.

Still, a characteristic city landscape was formed by Los Angeles’ skyscrapers.

Sunlight and smog in Los Angeles in 1973.

Shrouded Skies of 1973 Los Angeles

In 1973 the City of Los Angeles was veiled by a dense layer of smog that obscured the skyline.

Key Details

  • Era: 1973
  • Visibility: Buildings were visible only by shape.
  • Agency: Environmental Protection Agency (EPA)

Visual Summary

At least the silhouette of the city’s structures could be discerned through the haze, despite the relentless cloud of pollution.

The Clean Air Act helped the city transform its polluted landscape.

Smog over LA monitored by NASA scientists and air pollution center in 1972.

Smog Over Los Angeles in 1972

Monitoring Activities

  • NASA scientists and the Air Pollution Center tracked the dense smog
  • Data collection began in 1972, giving researchers a baseline for future studies

NASA and Air Pollution Center

These institutions worked jointly to measure airborne particulates, ensuring that the levels of fine particles were well documented for subsequent analysis.

EPA Role
  • The Environmental Protection Agency supported the monitoring program, providing resources and technical guidance.
  • EPA’s involvement helped maintain the integrity of the data set.
Clean Air Act Impact
  • Over the decades, the Clean Air Act has reduced emissions from vehicles and industrial sources.
  • As a result, the air quality in Los Angeles has shown measurable improvement.

Despite climate action being taken in response to the city’s pollution, some issues persist.

Los Angeles reactive pollutant program, a multi-agency air pollution research study in 1973.

Los Angeles Air Quality Overview

Historical Context

  • 1973: A collaborative air‑pollution study involving multiple agencies examined Los Angeles’s pollutant levels.
  • Entity: The Environmental Protection Agency (EPA) played a key role in the research.

Current Status

  • IQAir reports: Los Angeles ranks as the second‑worst city for U.S. air quality, surpassed only by Minneapolis.
  • Global Ranking: The city holds the 72nd position among the world’s cities with the poorest air quality.
  • California Trend: Several Californian cities continue to appear on the list of the nation’s worst for air quality.

Conclusion

While extensive research has charted Los Angeles’s past pollution levels, its future air quality remains uncertain, underscoring the need for ongoing environmental monitoring.

Even today, smog can be seen in the city.

A layer of smog lingers above the downtown Los Angeles skyline on December 6, 2024. The National Weather Service on December 4 issued an air quality alert for the greater Los Angeles area until midnight on December 6.

Los Angeles Air Quality Alert in December 2024

National Weather Service Issued Warning

The National Weather Service announced an air quality alert for the larger Los Angeles region on December 2024. The alert targeted the Greater Los Angeles Area, covering the city’s urban core and surrounding suburbs.

Historical Context

  • The 2018 National Climate Assessment highlighted that climate change is expected to amplify existing air pollution problems across the United States.
  • According to the Fourth National Climate Assessment and NASA, even after the Clean Air Act improvements, Los Angeles still experiences frequent smog and hazy days.
Article Publication and Updates

This story was originally published in January 2020 and received an update in May 2025. The update included the latest meteorological data and climate assessment findings.

Key Takeaways
  • The December 2024 alert underscores Los Angeles’s ongoing smog challenges.
  • The 2018 assessment and NASA data illustrate how climate change could worsen air quality.
  • Even after the Clean Air Act, the city’s urban environment remains prone to poor air quality.