Eliminating requirements spurs building, and anger
David Wagner
covers housing in Southern California, a place where the lack of affordable housing contributes to homelessness.
Published April 22, 2024 5:00 AM
A parking meter stands on a curb in Echo Park.
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Chava Sanchez
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LAist
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Topline:
In car-centric L.A., thousands of new apartments are now being developed with little to no on-site parking. One recent analysis found that 73% of affordable housing projects being fast-tracked through a key city of L.A. program feature no on-site parking.
The reaction: Housing advocates say eliminating parking requirements in new apartment buildings brings down construction costs, makes rents more affordable and encourages residents to use climate-friendly public transportation options. Some neighbors who live near these projects worry any influx of renters without dedicated spots of their own will turn finding street parking into a bloodsport.
Why on-site parking is no longer a given: Changes in state law have allowed L.A. housing developers to ditch on-site parking in many areas — an idea that would have been unthinkable in previous decades. One 2022 state law prohibits cities from requiring parking in buildings located within half a mile of a major public transit stop. The state’s density bonus law also gives 100% affordable housing projects the option to reduce or eliminate on-site parking.
Read the full story: To learn how elected county leaders are reducing parking requirements outside the city of L.A., and why some developers still choose to offer on-site parking.
Drive to any busy part of L.A., and discussions often turn to parking within a matter of minutes. Go to any local government meeting on new housing, and parking tends to come up even faster.
So it may be surprising to hear that in car-centric Los Angeles, thousands of new apartments are now being developed with little to no on-site parking.
Some neighbors worry any influx of renters without dedicated spots of their own will turn the hunt for street parking into a bloodsport. But housing advocates say there are good reasons to build without parking. Eliminating parking requirements brings construction costs down and makes rents more affordable. They say lack of easy parking also encourages residents to use climate-friendly public transportation options.
“We all want to park free — including me,” said Donald Shoup, a UCLA urban planning professor. “The problem with parking requirements is that in some cases the required parking is so expensive that the developer never even thinks about proposing a development.”
Shoup literally wrote the book on this subject. His seminal 2005 text The High Cost of Free Parking explores how parking requirements have raised construction costs and reduced the types of housing that make financial sense to develop on expensive urban land.
That’s because, Shoup said, “a lot of buildings aren't built” due to parking requirements, “especially small apartment buildings.”
Why parking is no longer a given in new L.A. apartments
Recent changes in state law have allowed developers to ditch on-site parking in many parts of L.A. County — an idea that would have been unthinkable in previous decades.
Laura Friedman, a Burbank state assembly member, authored a 2022 law that bans cities from requiring parking in apartment buildings within half a mile of a major public transit stop.
The state’s density bonus law also lets 100% affordable projects reduce or eliminate on-site parking.
Most of L.A.’s new low-income projects have zero parking
Developers in the city of L.A. are now seizing these opportunities, rolling out plans for thousands of new parking-free apartments.
A recent analysis from real estate data firm ATC Research found that 73% of projects being proposed through L.A. Mayor Karen Bass’s affordable housing fast-tracking program ED1 feature no on-site parking.
Some of those projects have drawn the ire of neighborhood groups.
“We have neighbors who have lived in our neighborhoods for years and they are accustomed to using a car,” said Conrad Starr, president of the Greater Wilshire Neighborhood Council, which has expressed opposition to two ED1 projects in Larchmont and Windsor Village with no parking.
Existing residents may end up needing to park many blocks away from where they live, Starr said, which can pose real challenges for senior citizens or families with young children.
“I'm primarily a bike rider, and I wish more people would ride bikes,” Starr said. “While we are creating new solutions as a city, and new opportunities for lifestyles that don’t require owning a personal car, that's just not going to solve it for everybody who's already here.”
Starr said one recent neighborhood council meeting regarding an ED1 project in Larchmont drew record attendance. Opponents flooded the council with letters expressing concern about the 52-unit affordable housing project’s lack of parking.
Parking is almost impossible both on weekends and weekdays, completely inconveniencing residents who live on streets adjacent to Larchmont Boulevard. This is the wrong place for more development.
— Karen Fischer, neighborhood resident
“Those of us who live nearby and shop in Larchmont know how crowded the streets are,” wrote resident Karen Fischer. “Parking is almost impossible both on weekends and weekdays, completely inconveniencing residents who live on streets adjacent to Larchmont Boulevard. This is the wrong place for more development.”
A Metro Rail train carries passengers toward Los Angeles along the 210 Freeway.
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David McNew
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Getty Images
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On-site parking boosts construction costs, increases rents
Housing advocates say eliminating parking requirements has enabled developers to build lots of new housing that’s affordable to L.A. renters with lower incomes.
Most ED1 units will be reserved for households earning up to 80% of the area’s median income — $70,650 for a one-person household — with studio apartments renting for no more than $1,766 per month under current limits. If parking were required in these buildings, ED1 proponents say, rents would be much higher.
What's more important — more housing units or more space for cars? It's not a hard choice in my book.
— Scott Epstein, policy director for Abundant Housing L.A.
“When you're in an emergency of this proportion and you're trying to build housing for folks, what's more important — more housing units or more space for cars?” Epstein said. “It's not a hard choice in my book.”
Parking requirements continue in many areas
Parking mandates remain in place for L.A. County projects that are further away from major public transit options. But local lawmakers are slowly chipping away at those requirements.
Last week, the L.A. County Board of Supervisors voted in favor of rules for unincorporated parts of the county requiring one parking spot per apartment — regardless of the number of bedrooms — in buildings with 10 units or less. Previous rules often required two spots per unit.
The new rules also allow larger projects to cut the amount of required parking by up to 50% if developers provide perks such as car-share spots, electric bike charging or space for small grocery stores.
The five-member Board of Supervisors voted unanimously to pass these parking reductions, but not without some trepidation. Before the vote, Supervisor Janice Hahn said, “I think we're going to have some unintended consequences from this — some problems.”
What L.A. housing looked like before parking mandates
Gartz Court in Pasadena is an example of a bungalow court, which were popular in Southern California before cars became the dominant form of transportation.
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Aaricka Washington
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Epstein said Abundant Housing L.A. had hoped to see the county stick with an early draft of the rules, which removed parking mandates entirely for projects with 10 units or less.
He points out there’s precedent in L.A. history.
“I used to live in a bungalow court,” Epstein said, referring to the small, detached rental home complexes developers once built here at large scale. While most of these bungalow courts predate the widespread adoption of automobiles, Epstein said, “The building form, I think, is still very relevant for Los Angeles.”
Shoup, the UCLA professor, said the dawn of parking requirements in the early to mid-20th century all but killed the bungalow court and other low-rise forms of rental housing that didn’t allow for the required two parking spots per unit.
“The dingbats disappeared, but so did almost all small apartment buildings,” Shoup said. “The kind of housing that people loved in L.A. was just swept away by the first parking requirements.”
Some developers still choose to provide parking
Getting rid of parking requirements hasn’t meant that L.A. developers are always choosing to eliminate parking. Many still plan to provide it.
Tracey Burns is vice president of Century Housing, a lender for affordable housing projects in L.A. She said nixing parking makes the most sense in areas with plentiful bus lines or train stations. Car-free tenants in those neighborhoods appreciate not having to pay more for a parking spot they’ll never use. In less transit-rich areas, discounted rent might not be enough to lure tenants who still rely on cars — and a place to park them.
“In areas such as the San Fernando Valley, where Metro transportation is limited, we as a lender will put on our risk hat and assess whether this development would be able to fully lease up,” Burns said.
There’s also a state bill that, if passed, could make it difficult for tenants to own a car in one of these buildings. Senate Bill 834, authored by Sen. Anthony Portantino of Glendale, aims to ban cities from issuing overnight street parking permits to residents in new parking-free apartments.
We know that the elimination of parking does not reduce vehicle ownership. Angelenos still depend on their cars.
— Tracey Burns, Century Housing vice president
“We know that the elimination of parking does not reduce vehicle ownership,” Burns said. “Angelenos still depend on their cars. But we also know that people need a place to live before parking so it's kind of like a double-edged sword.”
Cars drive down Fairfax Avenue, where developer Jason Grant plans to build low-income apartments with no parking.
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Evan Jacoby
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Reality check: Will future Angelenos still need a place to park?
According to U.S Census Bureau data, less than 9% of L.A. County households are completely car-free. Some developers hope investments in public transit — and Silicon Valley efforts to make private car ownership obsolete — could one day reduce L.A.’s need for abundant parking.
Jason Grant, founder of Local Development LLC, recently attended an L.A. City Council committee meeting to speak against a challenge to a 100% affordable project he’s developing on Fairfax Avenue. Opponents with the group North Orange Grove Residents have seized on the 26-unit project’s lack of parking.
On his way to the meeting, Grant saw something that put the whole fight in perspective.
“I'm on Beverly and La Brea, and I'm looking left at this Waymo car,” Grant said. “There was nobody in the vehicle. It was driving itself.”
Grant estimated that excavating land and pouring concrete to create an underground parking structure for the Fairfax project would cost upwards of $1 million.
“Yeah, I'm going to remove a million-dollar parking lot,” Grant said. “Because the parking will probably become obsolete in the next five to 10 years.”
The city council’s planning and land use committee unanimously voted down the challenge to the Fairfax project.
How to watchdog your local government
For people who live in L.A., the Board of Supervisors and City Councilhave the most direct impact on housing in your neighborhood.
The best way to keep tabs on your own local government is by attending public meetings for your city council or local boards. Here are a few tips to get you started.
Find meeting schedules and agendas: City councils usually meet at least twice a month, although larger ones may meet weekly. Committees and boards tend to meet less often, typically once a month. You can find the schedule and meeting agenda on your local government’s website, or posted physically at your local city hall. Find more tips here.
Learn the jargon: Closed session, consent calendars and more! We have definitions for commonly used terms here.
How to give public comment: Every public meeting allows community members to give comment, whether or not it’s about something on the agenda. The meeting agenda will have specific instructions for giving public comment. Review more details here.
People extract ballots from their envelopes and prepare them to be scanned for counting in the Vote-By-Mail Processing Boards area at the Orange County Registrar of Voters Facility in Santa Ana, Calif. on Oct. 28, 2026.
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Apu Gomes
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Topline:
A federal judge has denied an unprecedented, emergency request by the Department of Justice to segregate thousands of California ballots in the midterm elections.
What the court said: In his 26-page ruling issued this evening, U.S. District Judge David Carter, a Clinton appointee, denied the Justice Department's request for a temporary restraining order to stop processing the ballots in question. "Never before in American history has the federal government, on the eve of an election, sought to coerce a state and local government to abandon their own Constitutional elections procedures and bend to the will of the Executive Branch," he wrote. Carter also expressed concern about taking action that could disenfranchise eligible voters and create chaos.
The backstory: The Justice Department wants California election officials to stop processing ballots pertaining to 20,000 individuals that federal officials say are "likely" noncitizens. State and local officials in California have countered that the DOJ’s list of “likely” noncitizens is unreliable, with a preliminary analysis by Los Angeles County showing that many on the list do not have active voter registrations.
What's next: The judge said that the federal government can address the issue by continuing to indict people for the crime of illegally voting as noncitizens. DOJ officials say in the last two months they have charged dozens of people for registering or voting without being a U.S. citizen.
A federal judge has denied an unprecedented, emergency request by the Department of Justice to segregate thousands of California ballots in the midterm elections.
The Justice Department wants California election officials to stop processing ballots pertaining to 20,000 individuals that federal officials say are "likely" noncitizens.
State and local officials in California have countered that the DOJ's list of "likely" noncitizens is unreliable, with a preliminary analysis by Los Angeles County showing that many on the list do not have active voter registrations. The officials also claim that setting aside ballots just days before Election Day, when voting and processing mailed ballots are already underway, would be unlawful and infeasible and would disenfranchise eligible voters.
In his 26-page ruling issued Wednesday evening, U.S. District Judge David Carter, a Clinton appointee, denied the Justice Department's request for a temporary restraining order to stop processing the ballots in question.
"Never before in American history has the federal government, on the eve of an election, sought to coerce a state and local government to abandon their own Constitutional elections procedures and bend to the will of the Executive Branch," he wrote.
Carter also expressed concern about taking action that could disenfranchise eligible voters and create chaos.
"Once a vote is segregated, lasting harm has occurred," Carter wrote at the conclusion of his order. "If the Executive can discount votes and threaten an ongoing election due to unproven allegations, then our democracy is in danger. This Court declines to be a party to such process."
The judge said that the federal government can address the issue by continuing to indict people for the crime of illegally voting as noncitizens. DOJ officials say in the last two months they have charged dozens of people for registering or voting without being a U.S. citizen.
The DOJ's lawsuit in California, which was filed Oct. 15, is among a flurry of unprecedented actions the department has waged in states close to Election Day, raising alarms about federal interference in state election procedures.
Like in California, on Monday federal prosecutors asked Washington state election officials to review a list of 400 registered voters the DOJ believes are likely noncitizens. And last week, the DOJ filed an unusual lawsuit in Alaska that seeks to stop the state from certifying the results in its Senate race if the Republican incumbent loses due to votes for a longshot candidate with a similar name who is accused of being a spoiler candidate.
In California's most recent motion to the court, state Attorney General Rob Bonta, a Democrat, asked the judge to take into account the circumstances of DOJ's demand. "This litigation is a precursor to further interference here in California," Bonta wrote. "The Court must not be drawn into this chilling degradation of democratic values and constitutional principles."
The Department of Justice is expected to appeal Carter's denial, and the matter could ultimately wind up before the U.S. Supreme Court.
The DOJ has argued the issue is urgent since ballots are already being processed. Once signatures are verified on returned mail ballot envelopes, the ballots are separated from their envelopes to retain voter confidentiality and it then becomes impossible to retrieve an ineligible ballot.
Federal prosecutors have argued that votes by noncitizens dilute the votes of U.S. citizens. Voting by noncitizens has been shown by audits and investigations to be extremely rare.
The accuracy of the DOJ's list of "likely" noncitizens is still an ongoing matter of dispute.
A Los Angeles County analysis of a small sample of people on the DOJ's list found that a significant portion had said in records they were born in the U.S. But U.S. Citizenship and Immigration Services senior official Nicolas Bartell contested that in recent court filings, writing that his office's review of those individuals found none were U.S.-born.
Bartell did acknowledge the review found four of those people "might have a claim to U.S. citizenship."
He also provided the court additional details about the federal government's methodology in creating the list in recent court filings.
But University of Delaware political scientist Kassra Oskooi, who has been tapped as an expert witness by voting rights groups who are intervening in the case, responded in his own declaration to the court that he believes USCIS's matching protocol "is likely to be unreliable."
Background: Last December, the CPUC awarded a grant to telecom company AVX Networks to install subsea fiber internet infrastructure between Orange County and the island.
Why it matters: Catalina Island is home to more than 4,000 residents, and it draws thousands of tourists each year, but the internet connection is often slow and unreliable. The lack of a reliable internet connection affects critical services on the island such as remote learning and emergency response.
The island is home to more than 4,000 residents, and it draws thousands of tourists each year. Its slow, unreliable internet connection affects everything from remote learning to emergency response.
Lance Ware is CEO of AVX Networks, the company awarded the grant from the CPUC in December 2025. He told LAist host Nereida Moreno that the island depends on a very limited wireless internet link.
“When the town is busy, for instance, a cruise ship comes … the internet just gets crippled along with all the telephone services,” Ware explained.
Months after AVX Networks was awarded the grant, CPUC staff accused the company in July 2026 of breaking federal spending rules, citing insufficient justification and documentation for invoices.
The proposed plan would build the fiber-optic network under the San Pedro Channel from two points on Catalina Island to landings near Huntington Beach. Those cables will then connect to the Middle Mile Broadband Network in Stanton.
Where do things stand today?
CPUC staff allege that AVX Networks violated several program requirements, according to records.
“Since the award, AVX Networks has not shown itself to have the requisite administrative, technical, and operational capacity to deliver on its project, and AVX Networks has failed to comply with the terms and conditions of its award,” the CPUC agenda item records state.
Ware said he “vehemently disagrees” with those statements.
“There are allegations on things in there that do not make sense to us in that we've had no due process or cure and correct period to address,” Ware said.
What’s next?
If the commission terminates the contract and pulls the funding, Ware said the project will be delayed, but not stopped.
“This is not curtains down for us,” Ware added. “It's gonna take longer, and we'll have to find some other way to finance it, but we certainly haven't given up.”
How to participate in CPUC meetings
California’s Public Utilities Commission meets on Thursday, Oct. 29 at 11 a.m. You can watch the meeting remotely here.
To make public comments over the phone: Call (800) 857-1917. When prompted by the operator, unmute your phone and press *1 (star one). You will be prompted to state your name and/or organization. The operator will call on you when it’s your turn to speak.
To make a written comment: You can submit comments on the CPUC docket page.
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Erin Rode
is working on election coverage this fall, along with other topics.
Published October 28, 2026 4:00 PM
More than 30 cities in L.A. and Orange counties have tax increases of some kind on the Nov. 3 ballot.
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Raymond Rivera
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Topline:
By LAist’s count, over 30 cities in Los Angeles and Orange counties are asking residents to approve tax measures on Election Day this Tuesday.
Why now? Municipalities cite stagnant revenues that haven’t kept pace with the rising costs of insurance, maintenance and infrastructure projects, and employee pensions. As a result, big cities, suburbs and small towns alike are all facing multimillion-dollar budget deficits. So they are asking residents to open their wallets — or potentially see deep cuts to basic city services.
Read on ... to find out if possible hikes are coming your way.
Southern Californians are feeling squeezed by the rising costs of, well, everything. And now their local governments are asking for more money, too.
By LAist’s count, more than 30 cities or districts in Los Angeles and Orange counties are asking residents to approve tax measures on Election Day, Nov. 3, citing stagnant revenues that haven’t kept pace with the rising costs of insurance, maintenance and infrastructure projects, and employee pensions. Big cities, suburbs and small towns are all facing multimillion-dollar budget deficits and asking residents to open their wallets — or potentially see deep cuts to basic city services.
The list of local measures on ballots from Culver City to San Clemente includes sales taxes, hotel taxes, business taxes, parcel taxes and utility taxes. Some ballot measures would extend or increase existing taxes while others are brand-new.
Much of the answer to why so many tax measures are on the ballot lies in Proposition 13, which capped property taxes in 1978.
Before Prop. 13, cities and counties relied on property taxes for nearly all of their revenue. In the decades since, they’ve increasingly turned to other types of taxes. Hotel and utility taxes, for example, were essentially nonexistent before the mid-1970s, and sales taxes represented a small sliver of revenue. Even as these taxes have grown, they’ve struggled to replace property tax revenue.
How Proposition 13 reshaped local taxes
Before 1978, California municipalities could raise taxes without voter approval. But in addition to capping property taxes, Proposition 13 also changed the rules for other taxes. Section 4 of Proposition 13 states that any special taxes (which are taxes designated for a specific use) must be approved by two-thirds of voters. A later proposition passed in 1986 requires that general taxes be approved by a simple majority of voters. General taxes are general purpose funds that cities can allocate as they please.
The rules could change again this year with Proposition 43, which would raise the share of votes needed to pass local special tax measures proposed by citizens to two-thirds. Currently, citizen-led special tax initiatives only need to win a simple majority.
Despite what the Nov. 3 ballot might suggest, sales tax measures are actually becoming less common, according to Michael Coleman, author of the California Local Government Finance Almanac. “More and more governments have started to exhaust the capacity for that. There’s a limit in how much you can do both legally and in terms of the tolerance of voters,” Coleman said.
State law caps the maximum combined local and county sales tax rate, and many Southern California cities are already at or near that cap, Coleman said. And sales tax isn’t as reliable as it used to be, amid the broader retail downturn and shift to a service-based economy (most services aren’t taxable in California).
All of that means cities are increasingly turning to “ticky-tacky, peculiar taxes” to come up with revenue, according to Kirk Stark, a professor of tax law and policy at UCLA.
The “conventional tax instruments” — property, income and sales taxes — are all limited by state law, Stark said. “Local governments that are hoping to satisfy demand for any kind of public expenditure have to turn to other, less conventional sources of revenue.”
This year, cities are asking Southern Californians to say yes to a wide range of taxes. Below, we look at three examples in South Gate, Orange and Diamond Bar.
South Gate: A utility users tax
South Gate is asking voters to approve something less common: a utility users tax, or UUT for short. If Measure SG is approved, the 8% tax would be added to bills for utilities such as electricity, water, natural gas, cable and phone service. The tax would bring in an estimated $10.4 million per year.
The city is facing a potential fiscal emergency and a $9.4 million budget deficit. Earlier this year, South Gate began cutting back services, including eliminating its crossing guard program and assigning fewer police officers per shift.
At a City Council meeting on the tax measure earlier this year, several residents spoke against the measure, with some calling the deficit a result of potential financial mismanagement that shouldn’t be pushed onto residents. Others said the monthly costs would simply add a new burden to already tight budgets.
“Being a homeowner here for the past 13 years, I have seen my utilities go up as well as the cost of living, my insurance for my house, and my car insurance go up. I believe there’s got to be a way to fix this problem without the UUT measure,” one resident told the City Council.
“I’m extremely frustrated that you now want to do electricity, water, sewer, cable, cell phone, gas. ... That hurts us. You’re passing that on to us, and that is absolutely not acceptable,” said another.
Most people don’t book a hotel in their own city. That’s made hotel taxes an easier pill to swallow for voters, since the tax is mostly levied on visitors.
The city of Orange is asking voters to approve Measure J, which wouldraise the hotel tax from 10% to 14%. Orange is one of 10 cities across Los Angeles and Orange counties where voters will decide in November whether to increase or establish a local hotel tax, also known as a “transient occupancy tax.”
Orange residents will also vote on a 1-cent sales tax measure, as the city projects a $27.6 million deficit that it calls “one of the largest financial challenges in the city’s history.” The sales tax is expected to bring in $37 million annually, and the hotel tax would add $3 million.
Diamond Bar: A new 1-cent sales tax
Diamond Bar voters will decide on Measure Q, a 1% local sales tax that would add a penny per dollar to purchases of taxable items. The city estimates the tax will bring in an additional $6 million annually, which could help plug a projected budget deficit of $5 million a year by 2030.
“The city’s challenge is simple: costs for city services are going up faster than revenues,” states Diamond Bar’s fact sheet on the measure, which cites rising public safety costs and $100 million in infrastructure and maintenance needs.
Several other cities have local sales tax measures on the ballot, including Santa Ana’s 1.5% sales tax extension and Los Angeles’ sales tax increase for the Los Angeles Fire Department, Measure FD.
“There’s a variety because circumstances among these local governments vary. The types of economies among governments vary, the local conditions, even the preferences for what type of revenue measure or tax measure might work varies,” Coleman said. “A local government that’s looking at one of these is going to look at a number of different options and consider what might be most palatable to the voters in their community.”
What’s on your ballot?
Our LAist Voter Game Plan is here to help guide you through the Nov. 3 election with guides to races across Los Angeles and Orange counties — and that long list of state propositions — to help you cast a ballot that’s in line with your own personal beliefs and values.
But the one thing we don’t do? We don’t tell you how to vote. That part is left up to you.
A firefighter battles the Eaton Fire, Jan. 8, 2025, in Altadena, Calif.
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Ethan Swope
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Associated Press
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Topline:
At the height of the Los Angeles fires in 2025, millions of residents were exposed in a 24-hour period to toxic lead levels from smoke that were 80 times higher than the typical background level, according to a new study. Researchers from the California Institute of Technology compared the chemical composition of smoke from the Eaton Fire with that of a wildfire and found that the urban plume had more lead, arsenic and halogens (which include chlorine and bromine) linked to burning vehicles, building materials and electronics.
Why it matters: “The main, key finding is really that wildfire smoke is very different fundamentally from the urban smoke,” said Nga Lee “Sally” Ng, an author of the study published Wednesday in the journal Science Advances. With the new technology they used to measure what was in the smoke, they were able to “actually see the very detailed component of these particles that we are breathing.”
Health effects: Ed Avol, professor emeritus in the Keck School of Medicine at the University of Southern California who has researched the health effects of air pollution for decades, said significant exposure to heavy metals is consistent with what he’d expect, “but certainly surprising because we haven’t been able to document this sort of thing.” “One of the real advantages of this study is that it had the opportunity to make measurements sort of hour-by-hour across the sampling network. And typically we make measurements of airborne particulates and so forth a couple of times a week, at best,” said Avol, who wasn’t involved in the study.
The backstory: The two wind-whipped infernos in Altadena and the Pacific Palisades that ignited on Jan. 7, 2025, killed at least 31 people and destroyed more than 16,000 structures, mostly homes, and everything in them — cars, paint, furniture, chemicals under sinks and more. Millions of people were exposed to smoke, which across the entire United States has been linked to tens of thousands of deaths annually. A recent study found that metal mixtures in the leftover smoke, ash and debris from the deadly 2023 Maui wildfires were harmful to the lung health of people living nearby long after the burning ended.
At the height of the Los Angeles fires in 2025, millions of residents were exposed in a 24-hour period to toxic lead levels from smoke that were 80 times higher than the typical background level, according to a new study.
Researchers from the California Institute of Technology compared the chemical composition of smoke from the Eaton Fire with that of a wildfire and found that the urban plume had more lead, arsenic and halogens (which include chlorine and bromine) linked to burning vehicles, building materials and electronics.
“The main, key finding is really that wildfire smoke is very different fundamentally from the urban smoke,” said Nga Lee “Sally” Ng, an author of the study published Wednesday in the journal Science Advances. With the new technology they used to measure what was in the smoke, they were able to “actually see the very detailed component of these particles that we are breathing.”
Co-author Haroula Baliaka said understanding the different chemical compositions of smoke from an urban versus a wildland fire helps bridge a missing gap in research. Wildfires are growing larger, more intense, faster-moving and more frequent largely because of drier and warmer weather associated with human-caused climate change. As urban growth and climate change push more fires into cities, researchers said monitoring and emergency response will have to adapt.
Ed Avol, professor emeritus in the Keck School of Medicine at the University of Southern California who has researched the health effects of air pollution for decades, said significant exposure to heavy metals is consistent with what he’d expect, “but certainly surprising because we haven’t been able to document this sort of thing.”
“One of the real advantages of this study is that it had the opportunity to make measurements sort of hour-by-hour across the sampling network. And typically we make measurements of airborne particulates and so forth a couple of times a week, at best,” said Avol, who wasn’t involved in the study.
Thousands of structures burned, releasing toxic chemicals
The two wind-whipped infernos in Altadena and the Pacific Palisades that ignited on Jan. 7, 2025, killed at least 31 people and destroyed more than 16,000 structures, mostly homes, and everything in them — cars, paint, furniture, chemicals under sinks and more. Millions of people were exposed to smoke, which across the entire United States has been linked to tens of thousands of deaths annually. A recent study found that metal mixtures in the leftover smoke, ash and debris from the deadly 2023 Maui wildfires were harmful to the lung health of people living nearby long after the burning ended.
During the fires, researchers measured trace elements of fine particulate matter, or PM2.5, every hour reported by instruments in the Atmospheric Science and Chemistry mEasurement NeTwork ( ASCENT ), a relatively new network of air quality monitors across the U.S. that measures the size and chemical composition of these particulates in real time. Ng said ASCENT is the U.S.'s first measurement network able to measure the chemical composition of airborne particles in real time.
Researchers were able to see what chemicals were in the smoke, track how its composition changed over the fire’s course, and distinguish emissions coming from burning structures. From there, they estimated how many people across Los Angeles were exposed to the heavy metals, particularly lead, during the fire’s first days.
They compared the typical value of lead before the fires and the chemical makeup of smoke from a 2024 fire in Riverside County that burned mostly vegetation with data from the Eaton Fire plume. Contrasted with the wildfire smoke, the plume from the LA fire contained 50 times more lead, three times more arsenic, and seven times more halogens. At the peak of burning, about 7 million people were exposed for 24 hours to lead levels more than 80 times what’s typical.
Lead is a neurotoxin that can stunt children’s development, lower IQ scores and increase blood pressure in adults. Scientists still don’t know how short-term, high exposure to lead impacts human health. Arsenic exposure is associated with various cancers.
Yaguang Wei, assistant professor in the department of environmental medicine at Icahn School of Medicine at Mount Sinai who researches the health impacts of air pollution, wildfire smoke and severe weather, said their findings reinforced some conclusions of a recent study he co-authored that found, in part, that PM2.5 from wildfire smoke was more toxic than particulates from other sources.
“I think their findings are not surprising,” said Wei, who was not involved in the study. When fires burn properties, they’re also burning “a lot of lead on your wall paint and the plastics and electronics and those are very toxic” when they burn, he said.
Monitoring, policies and emergency response need to adapt, experts say
Wei said the study has “important policy implications.” He thinks governments should take stronger actions to protect public health during these fires by investing in more wildfire monitoring and public alerts, and having more prescribed fires.
For Avol, the study is a reminder of our “strange and increasingly dangerous new world” where urban and wildland intersect — and increasingly catch fire.
“It reminds us to be cautious and be concerned and, you know, think about what we can do to minimize this. We’re not going to stop using all these materials containing metals and halogens and so forth in our homes,” he said. “How do we protect people from being exposed to that?”
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