When the Eaton fire raced through Altadena and surrounding areas in January, the unimaginable disaster killed 17 people and destroyed 9,400 homes, businesses, schools and houses of worship.
While thousands lost literally everything, reducing the historic town of Altadena into streets of ash, charred wood and mangled metal, there was something else lost that went unnoticed, save for a group of scientists.
Nearly all of the air pollution monitors in Altadena were gone — destroyed in the fire.
To make up for the loss, scientists from Caltech and the Jet Propulsion Laboratory (JPL) in La Cañada Flintridge set up a dense thicket of rooftop air pollution monitors throughout Altadena to measure dust and ash particles in the air.
Previously, as part of a community science effort called PurpleAir.com, the Environmental Protection Agency joined with residents nationwide, including Altadena residents — who placed air monitors on their rooftops at their expense to help grow the nationwide network of monitors.
But since the fire, one glance at the AirNow and PurpleAir.gov map for Southern California reveals a blank spot in Altadena with nearly zero monitors for smoke, dust and “larger particle pollution” known as PM10.
“The fire map was empty. There was nothing there,” said Haroula Baliaka, a graduate student in environmental science and engineering at Caltech. “We asked: What can we do to help the community?”
Her boss, Paul O. Wennberg, a professor of atmospheric chemistry and environmental science and engineering, and the rest of her team set out on Feb. 23 to rebuild the Altadena-based air monitoring system.
They’ve installed sensors spaced one kilometer apart to create a grid, mostly on the roofs of still-standing buildings, and they’ve also mounted the monitors on whatever part of a building is upright. They’ve even affixed sensors on poles.
Each sensor is placed two meters above the anchored platform and is powered by a small solar panel to send continuous readings.
They aimed to finish attaching 25 sensors by the end of this week. As of Wednesday evening, 21 were installed, Baliaka said.
The grid restores data but goes one step further. PurpleAir sites only measure smaller particles of a little more than 2 microns, called PM2.5, which is more about the soluble air pollutants that can cause lung disease, asthma and emergency room visits.
The Caltech project, called the Post-fire airborne Hazard Observation Environmental Network for Integrated Xposure-monitoring, or PHOENIX, measures larger particles that are indicative of urban fire ash and dust.
The timing coincides with the start of debris cleanup at burn sites.
Cleanup is a two-edged sword. Residents want to get the debris removed and sent to a landfill so they can rebuild, but ash from an urban fire may contain metals and other particles that can “resuspend” in the air during cleanup and cause health problems when inhaled.
“If we don’t get any resuspended dust, you won’t see it in PM10. If we did get resuspended dust, PM10 would spike up,” Baliaka explained. Because the data is public, a homeowner or a worker can stop their cleanup, or water it down and secure it properly to prevent airborne particles.
Her team even placed a sensor where trucks drive by carrying ash and debris, she said.
“The Eaton fire was an urban fire,” Baliaka said. “Structures became the fuel. Lead pipes, batteries and plastics went up into the air and all that came down as dust and ash.”
As a critical phase of the cleanup begins, testing the air emissions very close to the cleanup sites is timely and necessary. At the very least, the PHOENIX map of sensors and readings will give people peace of mind that the air is safe to breathe, officials said.
“Knowledge is super important,” said Bill Wentzel, 69, of Altadena, where he and his husband Martin Lo lived before the fire. “It’s nice to know.”
“Whenever we visit our burned out house I get a headache,” said Lo. “You can smell it. The air smells like burned chemicals.”
A JPL team will install a sensitive air monitor at the closed Odyssey Charter School at 725 West Altadena Drive. The device will be operational by the end of March, said Carl Percival, senior research scientist and group supervisor of the Laboratory Studies and Atmospheric Observations at JPL.
It will be equipped with an X-ray fluorescence technique to identify heavy metal particles such as iron, cobalt, nickel and selenium, as well as black carbon, he said, and it will run 24 hours a day. JPL hopes to leave the device up through the town’s rebuilding process, he said.
“We all know particulate matter in air is an issue,” Percival said. “We want to provide data which will help local authorities decide if there’s any danger. While we are providing the data, it is up to the health experts to make decisions.”
The scientists also are working with CalEPA. Data will be shared with the South Coast Air Quality Management District, already doing mobile air emissions testing in the Eaton and Palisades burn zones, and the California Air Resources Board (CARB).
The collaborative effort will inform the state’s regulatory agencies on the safety of debris cleanup. And because it is being made public by Caltech, it keeps affected residents up to date on the local air quality.
“Residents impacted want to know if they can go back to their homes, is it safe to go back home and let their kids go out to play,” said CalEPA Secretary Yana Garcia, in an interview on Tuesday, March 18.
For JPL, the work is personal. About 200 employees out of about 6,000 lost their homes in the Eaton fire, Percival said.
“I know colleagues who’ve lost their homes. And a lot of friends who’ve lost their homes,” he said. “I went into the burn zone last weekend and I was shocked how extensive it is.”
Though JPL has turned its research skills toward Mother Earth before, it is more known for sending space probes to explore outer planets, including Saturn and its moon, Titan, as well as other objects in our Solar System.
“We look at all the planets. Earth is the one I really like because I live on it,” Percival said.
Baliaka said she sometimes calls a school or a property owner to ask if they’ll allow a sensor on their roof. She said she always receives a good reaction.
“I think people really care. They care about what they breathe,” she said.
Late Wednesday afternoon, Baliaka, her husband Nikos Kanakaris, a post-doctorate fellow at USC, and Coleen Roehl, associate research staff member at Caltech, were installing a sensor atop a non-affected school building at the closed Eliot Magnet Middle School in Altadena.
They climbed three ladders to reach the highest spot — so the sensor would not be obstructed and air would pass through it freely. They formed a human chain to hoist up the heavy wood pallet, tripod poles, cement blocks, sensor device and solar panel.
“It is definitely the hardest one we’ve done,” Baliaka said as she stepped onto the school’s upper roof with the equipment. Like clockwork, she connected the poles, hoisted the sensor two meters high and hooked it up to the solar panels.
“This is where the air gets pulled in,” she said, pointing to the sensor box. “It is working. You can hear it humming.”
To get a broader view of the burn damage from both the Eaton and Palisades fires, JPL has flown its aircraft, the Airborne Visible/Infrared Imaging Spectrometer-3 (AVIRIS-3), over the burn scars to measure the amount of ash and help with ash sampling, reported Gov. Gavin Newsom’s office.
The aircraft has helped state and local agencies quantify the debris surge being washed into the ocean after a rainstorm, said Christine Lee, a JPL research scientist in the lab’s Water & Ecosystems Group.
JPL satellites look at changes in the water color to determine ocean and coastal resiliency, she said. “We can also see things like oil slicks.” Lee said her fellow JPL scientists want their research to translate into positive action.
“It definitely hits home,” she said. “Everyone is trying to have their expertise contribute to the recovery.”