What air quality sensors around Boyle Heights warehouse are telling us

With kids headed back to classrooms for the school year, environmental health officials with LAUSD say there is no significant health risk from air contamination for students in Boyle Heights and the surrounding neighborhoods.

Residents, though, continue to worry about the health effects of air pollution from the Lineage warehouse fire. They're still reporting headaches, nausea and difficulty breathing weeks after the fire was put out.

The fire began June 17 and burned for nearly a week, sending a plume of thick smoke into surrounding neighborhoods.

Then, after the fire was extinguished, tens of millions of pounds of refrigerated food stored in the massive warehouse rotted, sending foul odors and pests into the surrounding neighborhood. Lineage said 92% of the food had been removed as of Tuesday.

What's being measured

Much of the air quality data collected in the area after the fire comes from South Coast Air Quality Management District sensors located at Eastman Avenue Elementary School and Robert Louis Stevenson Middle School, both of which are less than a mile from the warehouse.

They take readings on an hourly basis and publish the data online.

Here's what these air quality monitors have been recording over the last few months:

• PM 2.5: The sensors at the two schools have been monitoring fine particulate matter since they were installed on June 19. They are able to pick up particles as small as 2.5 micrometers, or about 30 times smaller than a human hair. Particulate matter, in this case, was mostly associated with smoke generated while the fire was active.
• Methane: The sensors started measuring methane on July 9. Methane is a greenhouse gas that can be harmful to the environment and is only harmful to humans at extremely high concentrations. The sensors have picked up levels that are fairly typical for the region.
• Hydrogen sulfide: The sensors started measuring hydrogen sulfide on July 9. Hydrogen sulfide creates what’s often described as a “rotten egg” smell, and is the chemical that caused some of the stench created by the rotting food left behind after the fire. Still, scientists say just because people can smell it, that doesn’t mean the levels of hydrogen sulfide are high enough to cause harm. They say they haven’t seen huge peaks.
• Ammonia: The devices were not equipped with ammonia sensors until July 23. Like hydrogen sulfide, the chemical is also created by rotting food. Unlike hydrogen sulfide, ammonia was also used as a refrigerant at the facility. Ammonia levels have spiked repeatedly since the sensors went into use, with the most recent spike at the beginning of August. Scientists say ammonia exposure can have adverse health effects, especially on children and other vulnerable populations. Officials say levels are not consistently high enough to pose a risk.

What additional testing found

The Air Quality Management District also employed mobile monitoring to test test for several other compounds in neighborhoods near the fire immediately after it started.

While officials reported finding high levels of particulate matter, they reported other pollutants — including hydrogen fluoride and several toxic metals — to be mostly fall short of public healths standards that would raise concern. For example: Levels of bromine and chlorine while elevated stayed below the state’s short-term exposure threshold, which officials say is not unusual during structure fires.

The L.A. Unified School District also tested for other substances, including lead and formaldehyde, and says schools in the area are safe for students. At the same time, they flagged that lead levels at two schools are higher than California’s acceptable standard.

South Coast AQMD did not respond to LAist's questions before publication time.

Air quality monitors near the Lineage warehouse measure four main substances: particulate matter, methane, hydrogen sulfide and ammonia. But scientists say there could be other pollutants that aren't being picked up.

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Allen J. Schaben

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Los Angeles Times via Getty Images

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Why ammonia is concerning 

Despite assertions from environmental health officials that the neighborhoods around the warehouse are now safe, some scientists and community members continue to worry about air pollution.

Jill Johnston, associate professor of Environmental and Occupational Health at UC Irvine, said the spikes reported in ammonia levels are particularly worrisome.

“Ammonia is an air toxicant. It's a respiratory irritant,” she said. “[It] can also cause eyes, nose, throat irritation, and suppression of your lung function.”

Johnston found that ammonia levels have been spiking ever since the sensors that pick up the chemical were installed in late July, and as recently as the last few weeks.

An analysis published Aug. 5 by the Community and Environment Research Lab at UC Irvine and East Yard Communities for Environmental Justice found high levels of ammonia in streets close to Lineage.

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Courtesy Jill Johnston

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UC Irvine

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Environmental health officials with LAUSD say the ammonia levels found at nearby schools were not persistent or widespread enough to amount to a health hazard.

Johnston stopped short of saying it’s definitely the cause of the symptoms local residents continue report, which include headaches, nausea and difficulty breathing.

“Those symptoms can come from a lot of different chemicals, so it's not like a linear correlation there,” Johnston said.

Still, she says there’s simply not enough understanding of how long-term ammonia exposure affects the human body, especially when it comes to children and other vulnerable populations.

Why it's hard to detect other pollutants

The ammonia could also be a sign of other contaminants that have yet to be tested.

“Ammonia may just be a marker of a whole mixture of pollutants coming from the site,” Johnston said. “We just totally don't know yet because those haven't been fully characterized.”

The bottom line is, Johnston says, air quality monitoring has its limits, and there is a lot that isn’t measured or understood when it comes to air pollution following industrial fires like the one at the Lineage warehouse in Boyle Heights.

The limitations go beyond industrial fires.

Scientists have developed technology that’s significantly more advanced than the standard sensors used by most air quality management officials for routine pollution monitoring. The more complex sensors can pick up a wider range of pollutants.

More advanced technology, however, is also more complicated to use, which limits its use in the field.

How to report an air quality issue

South Coast AQMD gives you three ways to file a complaint:

• Call 1-800-CUT-SMOG (1-800-288-7664)
• Visit www.AQMD.gov/Complaints
• Using the South Coast AQMD Mobile App

Be prepared to share:

• Date and time of what you experienced
• Type of air quality event (odors, dust, asbestos, smoke, etc.)
• Odor description (gas, chemical, rotten eggs or other familiar odor)
• Address or location of suspected source