But even the highest-quality filters capture only some of the dangerous ingredients of car and truck exhaust, and to be effective, experts say, they must be frequently replaced and the building’s ventilation system must run virtually full time with all doors and windows closed.

The city inspects new projects’ air-filtration systems, but the head of the Department of Building and Safety concedes that his office has no procedures for documenting whether the proper filters were installed and does not conduct follow-up inspections to ensure that they’re being maintained and replaced.

Air-quality regulators and health experts warn that relying on air filtration and other mitigation measures will not solve the health threat to residents moving into new homes along freeways — Southern California’s biggest conduits of pollution.

Yet, Los Angeles in 2015 issued building permits for 4,300 homes close enough to freeways to threaten occupants’ health — more than in any year over the last decade. Since then the city has permitted more than 3,000 additional units within the 1,000-foot distance where the city advises developers that residents are at risk from air pollution, with at least one just 60 feet from freeway traffic.

Mayor Eric Garcetti and other local politicians have opposed limits on how many homes can be built near freeways on the grounds that it would hamper efforts to ease Los Angeles’ severe housing shortage.

Builders agree, noting that additional restrictions on new construction will increase the cost of housing. “And we have a very, very high need for housing,” said Tim Piasky, who heads the Building Industry Assn. Los Angeles/Ventura Chapter.

Doug Haines of the East Hollywood Neighborhood Council told city council members at a recent hearing that fine particulates will damage the lungs of children in hundreds of new housing units proposed along the 101 Freeway.

“It passes through door jambs and window frames. There is no realistic way to filter it,” Haines said. “The only way to stop this is to limit all construction next to freeways.”

Researchers have for years studied how to protect the health of people living near traffic pollution.

In a report released in April, the California Air Resources Board reviewed more than a decade of scientific studies and highlighted what it said are “promising strategies” to help decrease pollution exposure for residents close to freeways when cities do not heed its warning against building homes within 500 feet.

Among the solutions endorsed by the agency are sound walls, vegetation barriers and “buildings with varying shapes and heights” to help disperse traffic pollutants.

“It’s basically giving people a second set of solutions to the problem,” said Bart Croes, research division chief at the Air Resources Board.

High-efficiency air filters are among the most effective tools, but neither the Air Resources Board nor most air-quality experts consider them an adequate fix.

What filters can miss

“Filtering the air for particles is better than nothing,” said Scott Fruin, a professor of preventive medicine at USC’s Keck School of Medicine. But he’s skeptical of cities that believe filters are an adequate solution. Studies show, for example, that high-quality air filters can capture some of the harmful particles in traffic emissions, but do not keep out toxic exhaust gases.

“The carbon monoxide, the volatile organics, benzene or 1,3-Butadiene, they’re going to be too high and the filtration won’t take care of that,” Fruin said.

Air-quality officials have also advised cities that the benefits of filters are significantly undermined if the building’s heating, ventilation and air conditioning system isn’t running at all times with all doors and windows closed.

UCLA doctoral student Amelia Mueller-Williams said that even though she tries to keep the windows of her student housing apartment near the 405 closed, she still finds black dust in tissues when she blows her nose.

“Our home is polluted in every sense of the word,” she said.

And such housing keeps getting approved.

In 2013, over the air district’s objections, the Los Angeles City Council unanimously approved developer M. David Paul’s 325-unit Il Villaggio Toscano project in Sherman Oaks right next to the 405-101 interchange. The city required only that the apartments have high-efficiency air filters and that certain windows facing the freeway can’t be opened.

Attorney Robert P. Silverstein, who sued the city, challenging its approval of the project on behalf of a neighborhood group, called such restrictions “a joke.”

“There’s a reason they call these kinds of apartments ‘black lung lofts,’ ” said Silverstein. “Some of these units are mere feet away from the busiest freeway intersection in the country.”

Rick Coca, a spokesman for Councilman José Huizar, who chairs the city’s Planning and Land Use Management committee, said Huizar voted for the Il Villaggio Toscano development because it had the support of the local council member at the time, Tom LaBonge.

Former Councilman LaBonge said he voted for the project because it had the support of the planning pepartment, was located on an empty parcel next to the Sherman Oaks Galleria mall and would help satisfy “the need for housing.”

 

Not all filters are alike

In April 2016 Los Angeles changed its building code to require high-efficiency air filtration in new homes within 1,000 feet of a freeway.

Filters are rated on a 16-point industry scale — the Minimum Efficiency Reporting Value, or MERV — that measures how effectively they block tiny pollution particles.

Studies of Southern California classrooms conducted by South Coast Air Quality Management District and UC Riverside scientists between 2008 and 2010 found that high-performance panel filters with MERV ratings of 13 to 16 removed between 70% and 90% of particle pollution. More common MERV 7 filters removed about 50%, the researchers found.

The state’s current filtration standard for new homes is MERV 6.

Under the ordinance Los Angeles adopted, filters must meet a performance rating of 13. The standards are similar to those in San Francisco, which since 2008 has required that level of air filtration in new housing near high-traffic roadways.

Los Angeles officials said they chose to require MERV 13 filtration in part because it was the most realistic option.

Shana Bonstin, a principal planner at the city planning department, said officials were concerned that if they set a more stringent standard “we could be setting ourselves up for a situation where the filters don’t get replaced or maintained: If we placed too burdensome of a requirement, would the trade-offs be too great?

“We wanted to find that perfect balance,” she continued, “where residents are provided the most protection and realistically the buildings were going to continue to maintain them.”

To work properly, all filters must be replaced between two and four times a year. And higher-rated filters are more expensive. A level 13-to-16 filter costs between $20 and $90, compared with $6 for a common MERV 8 filter, according to a December 2016 planning department report.

The city has in a few isolated cases required developers to install filters even stronger than those now required. Back in 2006, planning officials required developer G.H. Palmer to install level-16 filters at the Piero apartments near the 110 Freeway in Westlake to offer greater health protections to occupants, “removing 99.97% of all airborne contaminants at 0.3 microns,” according to a list of requirements imposed by the city as a condition of approval.

The city required similar MERV 16 filtration for the 335-unit Clarendon Apartments approved this year for construction on land abutting the 101 Freeway in Woodland Hills.

Jennifer Gordon, a spokeswoman for developer AMCAL Multi-Housing, Inc., said apartment units would be situated “a minimum of 60 feet from U.S. 101” and that the “community is purposely designed” to face away from the freeway, with a parking structure, a row of trees and a 60-foot residential building insulating areas of the development from traffic.

The City Council unanimously approved the project in March. Mayor Garcetti’s office signed off on it. Demolition has begun and the developer expects to finish construction by summer 2019.

Asked why he continues to approve such projects, Garcetti said: “Things have gone through because they’ve been in the pipeline and city council has approved those.” Stopping them, he said, would raise huge legal questions and be a financial burden for investors.

Garcetti said he has directed city staff to look at how the city’s zoning can be changed to protect public health.

Earlier this year council members and the mayor backed a new study of development restrictions, design standards and other steps the city could take. In a written statement, Garcetti’s spokesman said “no one should ever have to choose between affordable housing and breathing clean, healthy air” and cited a city sustainability plan that sets goals for reducing emissions, electrifying vehicles and increasing public transportation and transit-oriented development.

Neighborhood activists have long complained that the city has ignored or failed to enforce promises extracted from developers as conditions of approving their projects, including enhanced air filtration requirements for homes near freeways.

“There’s no filter police,” said Silverstein, the attorney who has challenged Los Angeles’ approval of residential projects. “The developers can say, OK, we’re going to do this. But it’s meaningless because the city is never going to go back and check.”

After inquiries from The Times, the Department of Building and Safety in 2014 found that two apartment complexes developed by Geoffrey H. Palmer — the 526-unit Da Vinci apartments and the 913-unit Lorenzo, both along the 110 freeway in L.A. — had failed to install the proper-strength filters or the equipment necessary to accommodate them.

At the city’s request, the developer of the Da Vinci later installed more powerful fan motors in the ventilation system to support thicker filters, said Jeff Napier, a spokesman for the city’s Department of Building and Safety.

At the Lorenzo, where lower-strength filters were already in place, the developer installed new ones “with larger surface area to accommodate the existing equipment,” Napier said.

Napier said he was not aware of any other projects where the Department of Building and Safety had stepped in.

Councilman Huizar said he hoped the city’s latest filtration rules would improve things “by making this a uniform baseline regulation instead of a case-by-case condition.” He has asked city staff for data on how the air filtration standards are going and said “we all want assurances that the program is being implemented.”

Have the right filters been installed?

The Los Angeles Department of Building and Safety inspectors review building plans and verify air-filtration standards “throughout the project, up to and including the final inspection,” Napier said. But the city ​​​​doesn’t keep records documenting whether high-grade air filters were installed as they do other health and safety features, such as smoke detectors.

“There’s no set form that checks a box that absolutely the filters were installed,” Napier said. “We have a construction boom going on right now. It would be counterproductive to document every little thing that we approve.”

Unless it receives a complaint, the city does not conduct follow-up inspections to see if air filters are being maintained and replaced because there is no requirement in the building code, said Frank Bush, the building and safety department’s general manager.

“That’s on the building owner,” Bush said “If we got a complaint we would take action, but nothing proactive.”

Mayor Garcetti said he supports a mandatory “check box” to track whether the promised air filters are being installed.

“That would be an easy thing to fix if they’re not,” Garcetti said. “This is not a sink finish, this a health issue and so it should have the highest priority.”

The new filter standards will not help the 600,000 people who, a Times analysis of 2010 U.S. census data indicates, were then living within 1,000 feet of Los Angeles freeways.

One of them is Victor Johnson, 61, who has three air-filtration machines running in his one-bedroom apartment about 300 feet from the 101 Freeway in Studio City. He said he hasn’t seen much improvement in his air quality.

He blames his ongoing health problems, which include chronic headaches, colds, inflammation and high blood pressure, on the pollution, which leaves a layer of fine black dust on his shelves and counters.

“Three filters and still this ultra-fine dust that’s a fine, fine black powder,” Johnson said. “I’m concerned about my lungs. I can deal with the embarrassment of my furniture being dusty. But I don’t want the same issues as a coal miner.”