The Brief

Gross black dust on your windowsill. Sickly yellow haze that obscures the mountains. Childhood memories of recess cancelled due to smog alerts.

You know the air here is dirty. Now learn why.

Once Upon A Time

The L.A. smog story goes a little like this: on July 8, 1943, a mysterious haze descended on the city.

"People were having car accidents," Chip Jacobs, co-author of Smogtown: The Lung-Burning History of Pollution in Los Angeles, told LAist. "Mothers were wondering why their kids' eyes were watering. Police officers were spinning loopy."

What was this strange haze? Was it a gas attack? Smoke from factories? From some distant fire?

To solve the mystery, local officials formed the nation's first air quality regulator, the Los Angeles County Air Pollution Control District. They began looking into the problem and quickly learned that there were a lot of sources of air pollution in greater L.A.: people burning trash in their backyards, oil refineries, smudge pots (which are small, smoky fires used by citrus growers to keep trees warm at night), and factories.

But soon, a Caltech scientist figured out that cars and gasoline were largely to blame for the eye-watering, lung-searing haze.

A smog-shrouded view of downtown Los Angeles on October 7, 1968.

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Los Angeles Public Library archive

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What Do Cars Have To Do With It?

Car exhaust has two main components: hydrocarbons, from the gasoline, and nitrogen oxides, which are formed inside hot, internal combustion engines. Both are harmful in and of themselves, but when they float into the sunny, Southern California air, the sunlight bakes them into a new chemical: ozone, also known as smog.

Once scientists figured out what caused smog, the crackdown began: in 1967, a new state air quality agency, the Air Resources Board, was formed. It enacted tailpipe emissions standards for cars. It required catalytic converters on new models, cleaner gasoline and, at the gas pump, those little rubber boots that trap fumes from the nozzle. In 1984, smog checks began statewide. Other industries had to clean up, too: oil refineries, cement plants, power plants. And as California cleaned up its air, other states and the federal government followed.

L.A. has the worst ozone, or smog, in the country, according to the American Lung Association's 2021 State of the Air Report.

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American Lung Association

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Bad Now Vs. Bad Then

The air is a lot cleaner now. In 2020 , we had 157 days of unhealthy air, compared to well over 200 in the late 1980s. However, 2020 tracked the highest number of unhealthy air days since 1997, even with pandemic restrictions seeing a drop in auto travel. So when it's smoggy, it's not as smoggy as it used to be.

But Los Angeles still has the worst smog in the country, according to the American Lung Association's 2021 State of the Air report. (Again, scientists call smog "ozone." But they're the same thing).

Greater L.A. exceeded federal air quality standards for 157 days in 2020.

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South Coast Air Quality Management District

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Part of the problem is that it's been hot, incredibly hot. And heat speeds up the process of ozone-formation. Experts are trying to figure out whether the spate of bad air is a new trend, reversing years of steady progress.

"Is this weather, or has this become climate?" said Atwood. "We're grappling with that question basically."

What Makes Our Smog So Special?

Three reasons.

• One, there are a lot of us, and we own a lot of cars. Angelenos own 0.54 vehicles per person, compared to 0.43 in New York City. Also, we have the busiest ports in the country, which means tens of thousands of heavy-duty diesel trucks are on our roads, and they are way dirtier than cars.
• Two, the mountains that ring the L.A. Basin trap that pollution as it gets pushed eastwards by sea breezes.
• And three, our climate. Nearly three out of four days in L.A. are sunny. And the L.A. Basin frequently experiences a weather pattern where a layer of warm air will sit on top of a layer of cooler air and prevent it from dispersing. That traps pollution closer to the ground. Think of it like putting a lid on a pot.

Where's The Dirtiest Air? Where's The Cleanest?

Because the wind blows smog east, towards the mountains, the air is worst there. So places like Redlands, San Bernardino and even the tiny, mountain community of Crestline have far worse air quality than coastal cities like Long Beach or Santa Monica.

But there's another factor to consider besides smog: the raw vehicle emissions that combine to make smog can also have localized health impacts. So if you live within 500 feet of a busy road or a freeway, you're in a pollution hot spot, because that's where vehicle emissions are the most concentrated. (Use this handy map made by our friends at the LA Times to figure out how close you live to a freeway.)

Trucks on the SR 60 Freeway drive by Anna Gallegos' backyard in Mira Loma Village, California.

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Andrew Cullen for LAist

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In the very worst places to live, like near a freeway in San Bernardino, you will be exposed to both smog and raw vehicle emissions, said Ed Avol, the head of the Environmental Health Division at the USC Keck School of Medicine.

"It's sort of like a double whammy, so you get both the local impact of being near a roadway, and you also get the accrued accumulation of pollution that's become a regional issue," he said in an interview with KPCC/LAist in April.

What Will Breathing Dirty Air Do To Me?

When you breathe in dirty air, it triggers an inflammatory response in your body. And once that happens, a lot of bad things can happen. In the short term, air pollution can cause:

• Difficulty breathing and chest pain.
• Increased rates of asthma.
• Respiratory diseases like bronchitis and pneumonia.
• Lost school or work days.
• Doctor and hospital visits.
  

Over the long term, it's much worse. Kids who grow up breathing dirty air, whether it's from living near a freeway or in a smoggy area, or both, have weaker lungs that don't work as well.

"If they never get that maximum lung growth early in life, it looks like it's permanently lost," Avol said.

For older adults, air pollution can contribute to cognitive decline, memory loss and premature death. It can also exacerbate heart disease, diabetes, obesity and cause cancer. There's even research suggesting fetuses are harmed when their moms breathe dirty air.

"In a cynical, joking way, you could say we believe air pollution causes everything," Avol said.

Smog-making cars on March 22, 2006 in L.A.

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David McNew/Getty Images

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How Can I Protect Myself And My Family From Bad Air?

One of the most common ways people are exposed to pollution is while driving. So when you're on the freeway, be sure to keep your windows rolled up and re-circulate the air, instead of drawing it in from the outside. Changing your air filter also helps. And new cars are more tightly sealed than older cars, keeping pollution out.

If you can, try to live at least 500 away from a freeway or busy road. If you can't, using HEPA air filters has been shown to significantly reduce indoor air pollution when the air outside is dirty. Clean that black dust, which is a combination of diesel soot and rubber dust from tire wear, off your window sills.

Outside of the home, try to walk or bike on less busy streets, to limit your exposure to vehicle exhaust. When waiting for the bus, stand back from the street corner, where pollution levels soar when vehicles accelerate from a stop. And don't exercise near busy roads during rush hour, especially in the morning, or when the air is especially bad.

You can also check the air quality every day. This South Coast Air Quality Management District map will give you a good overview of air in your area. You can also check the Purple Air network, which measures particulate matter (like soot, dust and wildfire smoke), or have a low-cost air monitor installed at your home or work.

What Do We Need To Do To Make The Air Actually Clean?

It all comes down to transportation. Cars and trucks make up nearly 90 percent of the smog-forming pollution in Southern California (not to mention they are also the largest emitters of greenhouse gases in the state), and it's because they run on gasoline and diesel.

Switching to fuels with zero tailpipe emissions, like electricity and hydrogen fuel-cells, will make a huge difference, says Will Barrett, the clean air advocacy director for the American Lung Association.

Trucks drive along Interstate 80 on February 18, 2014 in Berkeley, California.

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Justin Sullivan/Getty Images

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"We need to see more focus and urgency on the conversion of the heavy duty sector to zero emission technology," he said.

But heavy duty trucks have proven tricky, so far, to electrify, because they would require a massive battery to power them over long distances while carrying heavy loads. Also, truckers would need frequent, convenient charging stations, and that infrastructure doesn't exist yet.

California regulators, ever the clean-air optimists, are throwing cash at the program. The ports of L.A. and Long Beach, for example, have a goal of shifting their entire fleet of largely diesel trucks and equipment to zero emissions technology by 2035 -- at a cost of $14 billion. If they can figure it out, all of our lungs will benefit.

This story is part of Elemental: Covering Sustainability, a multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.

The Japanese American National Museum announced today it will reopen in January after a two-year, $25 million overhaul of the country’s largest museum dedicated to the Japanese American experience.

The museum in L.A.’s Little Tokyo is reshaping its galleries and expanding its signature exhibition to include more perspectives and connections between Japanese American history and current debates over race, immigration and democracy.

The new exhibition at JANM features A.I.-assisted avatars of Japanese American survivors of incarceration.

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Courtesy of Japanese American National Museum

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“We want to tell the story in a way that is more expansive and that other immigrants, communities can see their own story reflected,” said Ann Burroughs, the museum’s president and CEO.

That effort to tie history to the present comes as JANM itself has faced political pressure, with the museum losing federal funding amid Trump administration cuts.

From the outside, visitors returning to the museum, which has been closed since January 2024, will recognize its modern, minimalist exterior. Once they step through the doors, though, the experience will be vastly different.

The biggest change will be the installation of a 9,200-square-foot permanent exhibition occupying nearly all of the museum’s first floor — more than twice the space of the exhibition it replaces.

"Common Ground," which opened in 1999, covered Japanese American history from migration to the U.S. in the 1800s to the passage of a federal law — the Civil Liberties Act of 1988 — that formally apologized for the incarceration of Japanese Americans during World War II and provided $20,000 in reparations to surviving detainees.

The new exhibition, called "In the Future We Call Now: Realities of Racism, Forging Democracy," will include more recent history, such as Japanese American support for reparations for Black Americans and vocal opposition to the Islamophobia that swelled after 9/11. It will also cover the Japanese American response to ICE detention and incarceration of migrant children, drawing parallels to World War II camps.

Galleries have been reconfigured to include more recent history and more objects from the past, including kimonos owned by women from Japan, who immigrated to the U.S. in larger numbers starting in the turn of the 20th century.

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Courtesy of Japanese American National Museum

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It will also bring lesser-known perspectives to familiar history through telling the story of incarceration from “women and mothers” and those incarcerated at Tule Lake, the camp in Northern California where Japanese Americans labeled as disloyal by the U.S. government were isolated during World War II.

“JANM hadn’t told that story before,” Burroughs said. “You can’t draw those parallels of what’s happening now if you don’t talk about the camps and if you don’t talk about Tule Lake.”

The new exhibition will also lean more heavily into audiovisual storytelling, using technology and archival media to make the history feel more immediate.

The interactive “StoryFiles” incorporate AI so visitors can pose questions to digital avatars of incarceration survivors like the actor George Takei.

Burroughs stressed that the museum is not using generative AI, but drawing upon hours and hours of interviews in which subjects answered hundreds of questions.

The new exhibition will also draw deeply from JANM’s extensive collection of Japanese American home movies, including footage dating to the 1930s, and give visitors a window into everyday life before World War II.

Some of JANM’s best-known objects will be included in the new exhibition, like barracks from the Heart Mountain incarceration camp in Wyoming and a model of Manzanar in California’s remote Owens Valley, the first of the camps to be built.

The museum is also emphasizing everyday culture, with displays ranging from kimonos brought by Japanese immigrant women at the turn of the 20th century to rice cookers, and the worldwide reach of Hello Kitty.

The Hirasaki National Resource Center has been relocated to the second floor and will showcase work from artists like Ruth Asawa and Isamu Noguchi.

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Courtesy of Japanese American National Museum

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The larger new exhibition was created without growing the museum's footprint through reconfiguring the building. For example, the museum’s Aratani Central Hall will take on a new role as the museum’s main entrance, with visitors entering through its sweeping curved glass wall and moving directly into the exhibition galleries. But Burroughs said the redesign will not come at the expense of the hall’s longtime function as a community space available to local nonprofits.

Upstairs, visitors will find reconfigured spaces including a new reading room filled with works and furnishings by Ruth Asawa and Isamu Noguchi. Behind the scenes, JANM has upgraded decades-old building systems such as its HVAC and elevators.

The museum overhaul was funded as part of a much larger $135 million fundraising campaign, Burroughs said. The rest of the campaign supports JANM’s operations and long-term financial stability, including about $56 million in endowment and board-designated reserves.

"You know, life is never secure in the nonprofit world or in the museum world," Burroughs said. "We have to do a lot more to build up our endowments. We just will keep going."

Public health officials are urging people to be wary of flea-borne typhus after a recent outbreak of the illness.

The outbreak in late July was centered in the Pico-Union neighborhood of Los Angeles. The L.A. County Department of Public Health said five people were hospitalized; all recovered.

The outbreak comes as typhus cases continue to tick up in L.A. County.

Cases have been increasing fairly steadily for more than a decade, but they nearly doubled over the last three years. The Public Health Department logged a record 220 cases in 2025, and officials say this year is on track to exceed that.

Public health officials say the increase is likely because human-animal interactions are also increasing. That could be due to human population expansions into areas with more animals, available food sources for wildlife in populated areas or more people owning pets.

The bacteria that causes typhus is transmitted from animals to humans through fleas.

Typhus can’t be passed from one human to another, and public health experts say the illness is completely treatable, especially if it’s caught early.

Outbreaks and how to prevent them

Most of the time, typhus cases are spread out across L.A. County. But sometimes, there’s a localized spread over a short period of time that turns into an outbreak.

Public health officials respond to a few of them in L.A. County each year.

Generally, outbreaks are triggered by high concentrations of host animals.

“Wherever these animals may be present or wherever they may be congregating, in those areas we can see an increase in the number of human infections,” said Dr. Aiman Halai with the L.A. County Department of Public Health.

The most common hosts for typhus are rats, opossums and free-roaming cats. When people or pets come in contact with host animals, they can pick up the infected fleas and bring them into homes, spreading them to other people and animals in the process.

Halai says a variety of factors can attract animals and lead to an outbreak, including overflowing dumpsters, overgrown vegetation or a well-meaning neighbor feeding local critters.

You can help prevent outbreaks by securing trash in bins, making sure food isn’t left outside, and ensuring pets are on up-to-date flea control medication. Cutting back overgrown vegetation and blocking off crawl spaces can eliminate places where animals can shelter in and around homes.

Halai also says it’s important not to feed wildlife.

Should you be worried?

Although public health experts are wary of the typhus uptick in L.A. County, the 220 cases recorded in 2025 in L.A. County are not overly concerning.

"That’s a very  low rate at the population level,” said Dr. Jeffrey Klausner, a professor of infectious diseases at USC’s Keck School of Medicine.

Typhus is an acute infection caused by bacteria known as Rickettsia typhi. Variations of the bacteria also cause other illnesses transmitted by fleas, ticks, lice and mites, including tick-borne Rocky Mountain Spotted Fever.

Doctors can test for typhus fairly easily, and it is treatable with antibiotics. Symptoms are similar to the flu, and can include fever, headaches, muscle aches and nausea. It can also cause rashes in some cases.

Most infections are mild, but they can cause hospitalization and, in rare cases, can be fatal.

Klausner said the concern is that testing for typhus is not always routine.

“The most important thing is that when patients come in to their doctor — and they have fever, they may have a rash, they may have headache, may have muscle or joint aches — that the doctor's thinking about potentially flea-borne infectious diseases because the treatment can be different,” Klausner said.

The best treatment for typhus is the antibiotic doxycycline. If a patient with typhus gets another type of antibiotic like penicillin or amoxicillin, the treatment may not be as successful.

According to Klausner, when presented with flu-like symptoms, it’s also a good idea for patients to tell their doctors if they’ve been around animals, spent time in an encampment or even just gone on a hike.

Topline:

Why it matters: The small amphibian is found in the grasslands of Southern California and the Central Valley. But habitat loss, urban sprawl and longer droughts have been threatening the species’ population in recent decades.

What the protections do: Now that the Western spadefoot is a candidate for permanent protections, any development project planned for Western spadefoot habitats will have to take the amphibians into account.

Some exceptions may apply: The commission did carve out exceptions for solar projects in the Central Valley. To take advantage of federal tax credit deadlines, some projects can continue to be built, as long as they protect breeding pools and curtail construction during the season when spadefoots are most active.

What conservationists say: Brendan Cummings, conservation director with the Center for Biological Diversity, said in Southern California the biggest threat to the Western spadefoot is not solar development: “It’s warehouses or data centers and road widenings and all manner of construction activities.”

What happens next: The California Department of Fish and Wildlife will conduct a year-long review to determine if the Western spadefoot should be permanently protected.