The Smoke Comes Every Year. Sugar Companies Say the Air Is Safe.

This feature is the central story of Black Snow, a series by ProPublica and The Palm Beach Post investigating the health impacts – and government failures – of burning sugar cane among poor communities in Florida. Lulu Ramadan (formerly at The Palm Beach Post, now an investigative reporter at The Seattle Times) and ProPublica journalists Ash Ngu, Maya Miller, and Nadia Sussman won several awards for the series, including a Kavli Award, an Online News Association award, and KSJ at MIT’s Victor K. McElheny Award. To see the full interactive graphics, read the story at ProPublica.

In the fall of 2019, brothers Donovan and Jayceon Sonson spent eight weeks lying in hospital beds, struggling to breathe.

The young boys, then 5 and 6 years old, had developed upper respiratory infections on top of the severe asthma they’d had since they were toddlers.

Anytime they left their apartment, they took their “medicine box,” a plastic bin filled with red inhalers, prescribed steroids and a pink nebulizer shaped like a kitten. When the hospital released the boys just before Thanksgiving, doctors sent the family home with guidance on how to protect the boys from future episodes.

Among the instructions: “Keep your child away from secondhand smoke.”

Thelma Freeman, the boys’ grandmother, stared at the note. She didn’t smoke. Neither did anyone in her home. The problem was all around her, she thought, coming not from smokers but from an industry that provides thousands of jobs in her town: sugar.

This 3D map is zoomed in on a region of Florida called the Glades, highlighted in green on a gray background. A few specific towns are pinpointed with white dots: West Palm Beach, Pahokee, Belle Glade, South Bay.
Freeman and her grandkids are among the 31,000 people who live in the towns that dot the Glades, an agricultural region in Florida defined by its vast cane fields that produce more than half the nation’s cane sugar.
The same map from the previous image is now overlaid with sugar cane burns, represented by yellow-orange dots, and plumes of smoke, represented by light yellow triangles. The burns lead to smoke across the Glades region.
Nearly every day during the winter and spring, sugar companies set fire to dozens of cane fields across western Palm Beach County. These burns are a harvesting method that rids the plant of its outer leaves but releases harmful smoke. Locals call the resulting ash that blankets their community “black snow.”
The same map of the Glades is now overlaid with a layer of smoke, represented by yellow-white semi-transparent shapes that overlap each other.
Each burn lasted less than an hour, but an average of 25 fields were burned every day in the four months analyzed by The Palm Beach Post and ProPublica. The practice disproportionately affects residents in Pahokee, Belle Glade and South Bay, where about a third of the population lives in poverty. The smoke rarely reaches wealthier, whiter cities like West Palm Beach.

For years, residents in Florida’s heartland have complained about the smoke and ash that blanket this patchwork of mostly Black and Hispanic communities.

And for years, state health and environmental officials have said the air is healthy to breathe. So has the sugar industry, the largest employer in the region, with more than 12,000 workers during the six-month harvest season.

That battle has now escalated in federal court. In perhaps the largest challenge to the multibillion-dollar industry in years, Glades residents are suing sugar companies, alleging that pollution from cane burning damages residents’ health. The industry denies those claims, arguing as recently as November that a government-run air monitor in Belle Glade showed the area is in compliance with the Clean Air Act, the landmark 1970 law aimed at protecting the public from harmful pollution.

The problem? State officials found that the monitor was malfunctioning as far back as eight years ago, and, as of last week, it was still not fit to gauge Clean Air Act compliance. Documents obtained through public records requests show that the Florida Department of Environmental Protection flagged the faulty monitor in 2013, telling their federal counterparts that it didn’t meet strict accuracy standards and wasn’t suited to determine whether the air quality meets the requirements outlined in the federal law.

The monitor could cost the state as much as $35,000 to replace. But even if it were working properly, the state and federal framework for measuring air quality fails to capture the impact of sugar cane burning, an investigation by The Palm Beach Post and ProPublica found.

That’s because federal regulators rely on 24-hour and annual averages to track a type of particulate matter — an inhalable mixture of pollutants and debris tied to heart and lung disease — that is emitted by cane burning. These averages sometimes obscure short-term pollution, a defining feature of Florida’s harvesting process.

Photo of a sugar cane field being burned, emanating smoke into the sky
A sugar cane burn sends out smoke from a field near South Bay. Photo by Thomas Cordy, The Palm Beach Post.

The Post and ProPublica set out to see what the air is like in the Glades during the burns. The reporters analyzed cane burn permits and plume data from the Florida Department of Agriculture and Consumer Services, which projected where smoke would travel. They also worked closely with six experts in air-quality and public health from universities across the country, including three in Florida, as well as with residents, to place outdoor air sensors that measured particulate matter. The measurements were not intended to assess compliance with the Clean Air Act. Rather, the goal was to see if residents were being exposed to pollutants in ways that current monitoring systems would miss.

They were.

The sensors captured repeated spikes in pollution on days when the state authorized cane burning and projected that the smoke would blow toward them, our analysis found. While particulate matter can come from a variety of sources, air monitoring experts said the findings suggest the pollution is likely coming from cane burns. These short-term spikes, lasting less than an hour, often reached four times the average pollution levels in the area. Health and air-quality experts added that this exposure poses health risks both in the short term and over the course of the monthslong burn season.

Other major sugar-producing countries are moving to end or sharply limit cane burning, acknowledging that the practice is harmful because it subjects those nearby to many of the same pollutants that come from smoking tobacco, albeit with less intensity than inhaling from a filtered cigarette. Brazil, which produces more than 20% of the world’s cane sugar, has been phasing out the practice for more than a decade after researchers there raised concerns about particulate matter emissions.

Each year in the United States, tens of thousands of people die prematurely from exposure to particulate matter. People of color are disproportionately exposed, according to research published in April.

Palm Beach County emits more particulate matter from agricultural fires than any other county nationwide, according to Environmental Protection Agency emissions estimates from 2017, the latest year for which data is available. Those emissions are almost entirely byproducts of cane burning: 98.5% of the agricultural acreage burned in the county since 2010 has been for sugar cane, according to data from the state agriculture department.

The experts who reviewed The Post and ProPublica’s sensor analysis said the findings suggest policymakers should bolster air monitoring in the Glades, begin considering shorter-term spikes in pollution that are not currently built into federal air standards, and study community exposure to these pollutants.

Gallery of two photographs: on the left, a photo of a wooden sign on the side of a road, reading "Welcome to Belle Glade, her soil is her fortune,"; on the right, a photo of a highway billboard advertising job opportunities from U.S. Sugar.
For many residents, life in the Glades revolves around the sugar industry. Companies like U.S. Sugar and Florida Crystals are the main employers in the region. Photos by Thomas Cordy, The Palm Beach Post.

As residents and the industry battle in court, federal officials also have been eyeing changes. Under former President Donald Trump’s administration, the EPA considered — and rejected — strengthening regulation of particulate matter, which could have included a lower threshold for 24-hour averages or requirements for measuring in shorter durations. In June, President Joe Biden’s EPA announced that it would review that decision, acknowledging that evidence shows long- and short-term exposure to particulate matter can harm people’s health, “leading to heart attacks, asthma attacks, and premature death.”

But while the federal agency weighs more protections for public health, Florida lawmakers moved in a different direction this spring, passing legislation to protect farmers from legal challenges over air pollution, with some elected officials arguing that there’s no evidence of poor air quality in the state’s sugar-growing region. Gov. Ron DeSantis signed the bill into law in April.

U.S. Sugar and Florida Crystals, the region’s two largest sugar producers, disputed The Palm Beach Post/ProPublica analysis, criticizing the news organizations’ air-testing methods. The companies praised the quality of Florida’s air, again citing data from the state Department of Environmental Protection.

“By ignoring this data and instead using unqualified and error-ridden data to create a false and misleading narrative, these outlets are deliberately causing doubt and disbelief that will undermine the trust that the Glades communities have in their public health system at such a critical time,” said a spokesman for U.S. Sugar.

Florida Crystals also emphasized the knowledge of its experts in criticizing the reporting. In a statement, the company cited its investment in “innovative technologies” and its mission to “sustainably supply” food. “Our commitment to advanced, smart farming practices and to being a responsible member of our communities is rooted in our heritage in generational family farming, which led us to pioneer organic sugarcane farming in the US in the 1990s and continues to drive our vision today and for the future,” the company said.

Yet residents reveal a different reality. Over the course of a year, The Post and ProPublica spoke with dozens of Glades residents, teachers, custodians, doctors, nurses and field workers about their experiences with cane burning. Some responded to automated text messages sent when the newsrooms’ monitors detected spikes in pollution, allowing residents to share descriptions of smoke and their reactions in real time.

Many of these accounts paint a picture of a community often left with little choice but to stay indoors to avoid the smoke and ash outside.

Freeman keeps her grandchildren inside when she sees black snow — almost every day for six months of the year, she said. On a February afternoon, Donovan, clutching his scooter, tried to slip past her from the covered porch of her apartment in Pahokee. It was the 7-year-old’s third time outside that month.

Pressing her palm to his chest, she stopped the boy before he reached the lawn. “Not today, baby,” Freeman said. Ash was in the air and settling on grass and a makeshift swing hanging from a tree.

“Why would I risk it when I know what will happen?” she said.

Thelma Freeman shows how a nebulizer, a machine used to deliver drugs to the lungs, is used on her grandson Jayceon.
Thelma Freeman demonstrates how a nebulizer is worn on her grandson Jayceon. Freeman’s other grandson Donovan, seated, also uses a nebulizer. Photo by Thomas Cordy, The Palm Beach Post.

To reach the Glades from Palm Beach, you have to drive about 40 miles west — a straight shot along State Road 80 from former President Trump’s Mar-a-Lago home. Beachfront mansions and luxury suburban communities give way to vast stretches of rolling green crops and yellow highway signs warning of smoke. At the end, amid the lush fields, is a string of small towns made up of modest houses along crumbling streets, aging apartment buildings and trailer parks.

Tucked between Lake Okeechobee and the Everglades, the land is composed of nutrient-rich black muck, ideal for growing cane. The U.S. government transformed the region at the turn of the 20th century by damming the lake and draining the water at its southern bend, turning the marsh into an agricultural mecca.

Photo of a roadway sign in front of a sugar cane field. The sign is a yellow square, reading: "CAUTION, FOG-SMOKE AREA."
A roadway sign warns of low visibility from cane burn smoke. Photo by Thomas Cordy, The Palm Beach Post.

U.S. Sugar was the first company to settle in the region, in the 1930s. Florida Crystals followed in the 1960s. The two companies would soon become the largest producers of cane sugar in the country. Today, there are more than 410,000 acres of cane, the largest field crop contained to a single area in the state.

Florida farmers produced 21 million tons of cane sugar in the 2019-2020 harvest season, more than half the nation’s supply. The U.S. Department of Agriculture estimated the value of Florida’s sugar cane crops at about $648 million in 2019, the most recent year for which data is available.

While the sugar industry brings jobs to the area, the Glades communities remain among the poorest in the state. In fact, in the 1980s, Belle Glade was “so racked by poverty and AIDS that foreign service trainees were sent there to prepare for the Third World,” wrote Michael Grunwald in his book “The Swamp,” a history of the Everglades. Little has changed. Today, the median household income hovers at just above $24,000 — less than half the statewide figure.

The area is home to migrant field workers from Central America and the Caribbean, as well as Black and Hispanic American families who have lived in the Glades for generations. Many rely on the sugar industry for jobs.

Burning the cane is the cheapest method to prepare it for harvest, allowing sugar companies to maximize profits.

How Sugar Cane Is Burned and Harvested

This series of four images shows how sugar cane is burned and harvested. In the first, a worker on a tractor is lighting a cane field on fire, smoke billowing up behind him. The second shows the burns, highlighting smoke coming up from the field. The third shows the aftermath of a burn, with plants' outer leaves withered and brown. The fourth shows cane stalks on a truck, about to travel to a mill.
1. Before harvest, a worker lights the cane on fire with a torch-wielding truck. 2. The burns release smoke containing pollutants harmful to people and the environment. 3. In roughly 15 to 40 minutes, the fire burns through the plant’s outer leaves. 4. The stalks are harvested and transported to mills to be turned into sugar. Photos by Thomas Cordy, The Palm Beach Post.

To cope with the smoke and “black snow,” the flurries of ash that carry into neighborhoods, residents have adopted a series of unwritten rules: If you can’t shut your windows in the heat, press an air conditioner filter against the opening to keep the smoke out; rush children inside at the first whiff of the familiar, acrid stench; brush the flakes off your clothes instead of rubbing them off, otherwise they’ll stain; and, importantly, keep an inhaler or nebulizer nearby.

Burning season brings an influx of patients complaining of breathing problems to clinics and hospitals, doctors and nurses said.

“I basically learned how to treat asthma when I moved here,” said Beverly Jean Hunt, a registered nurse at a pediatric practice in Belle Glade, where she moved from Miami in 1995. “[Patients] almost become accustomed to it so they know they have to come in early on. They tell us, ‘Cane season is starting,’ to get their prescriptions for asthma medication filled early.”

At some schools, administrators warn about smoky conditions in campuswide announcements. Teachers say that, during burning season, they cancel outdoor recess and send kids home after asthma attacks.

“The conditions can be unbearable,” said Sayed Moghani, a math teacher at Pahokee Middle School. “Sometimes, when kids miss too much class, I do home visits to check on them and I find out their parents just proactively kept them at home because of their asthma and the smoke.”

Despite complaints like this from educators, the industry is so intertwined with the community that it leases fields from the local school district. Rosenwald Elementary School in South Bay collects about $7,000-12,000 a year from U.S. Sugar, which harvests cane on district-owned land adjacent to the campus, Type Investigations and Grist reported last year. The Post and ProPublica identified two additional land-leasing contracts that the Palm Beach County School District has with sugar companies — one near the Pahokee Middle-High School campus and another near the district’s bus depot in Belle Glade.

Since 2015, some Glades residents have pushed back, working with the Sierra Club on a campaign to end cane burning.

Others have been successful at stopping the smoke from reaching their neighborhoods. In 1991, the wealthier, suburban communities of Wellington and Royal Palm Beach, east of the cane fields, flooded state officials with complaints about smoke and soot reaching their homes.

The Florida Department of Agriculture acted swiftly: It banned sugar growers from burning when the wind blows east.

Photo of a newspaper clipping from The Palm Beach Post in 1991. Headline: "Cane burning curbed to reduce ash, soot in the skies."
A 1991 article from The Palm Beach Post reports on tougher cane burning restrictions.

Officials with the Department of Agriculture, which is in charge of regulating cane burning, at the time said they were responding to intense criticism and a growing population that needed protection from smoke compounding urban pollution. “We’re trying to eliminate the potential problems for people having to breathe the ash and deal with stuff falling on their cars and in their swimming pools,” David Utley, an agriculture official, said at the time.

About 35,000 people lived in Wellington and Royal Palm Beach in the early 1990s, when the complaints first flowed. Today, about 31,000 people live in the Glades.

The more recent effort to curb burning in the area did appear to prompt Agriculture Commissioner Nikki Fried to announce a slate of changes to the state’s sugar cane burn program in October 2019. Restrictions on burning, such as denying permits when the air quality is poor, would minimize the impact of smoke, the department said.

The Florida Forest Service, the arm of the agriculture department in charge of cane burning, did deny more permits from October 2020 through March 2021 than it has on average in the last five harvest seasons, rejecting about 12% of requests, compared to about 5% in the past. Forest Service officials said they rejected requests on days when wind projections suggested the smoke wouldn’t disperse. Still, officials ultimately authorized roughly the same overall number of burns as they have in the past, with about 11,000 fires approved throughout the season, department data shows.

Fried’s changes don’t bar burning when the wind is blowing in the direction of the Glades, and residents and environmental advocates say the rules did little to alleviate the impact of the smoke reaching the neighborhoods.

Meanwhile sugar industry representatives have fiercely defended cane burning, denying that it causes major pollution or health problems.

U.S. Sugar recently ran an ad on a billboard in Belle Glade that reads: “The air out here is cleaner than congested urban areas.”

In Tallahassee, the sugar industry operates one of the most formidable lobbying forces in Florida. U.S. Sugar and Florida Crystals have individually outspent every other company in the state on lobbying at the administrative and legislative levels since 2018, when the state first started its digital lobbyist pay database, a Post and ProPublica analysis found. That includes outspending corporate giants like Walt Disney Co., Florida Power & Light, and HCA Healthcare.

At times, the two sugar companies combined employed more lobbyists than there are state senators. Over the objections of environmental groups, they’ve successfully lobbied lawmakers to change environmental regulations regarding water policies that affect farming operations.

But lobbying is only one reason sugar companies have so much influence; the other is jobs.

The industry is the largest in the Glades, employing more than 12,000 workers, both seasonal and permanent residents, during harvest season, which lasts about six months. Any change to harvesting practices would have a “significant economic impact,” Judy Sanchez, a vice president at U.S. Sugar, told The Post and ProPublica in an interview.

“For so many of us, this is the only way to make a living,” said Phyllis McAllister, a local teacher whose husband retired from a job at a sugar mill because of breathing problems that his doctor attributed to “weak lungs.”

“It would be nice to end the burning,” McAllister said, “but I don’t want my neighbors to lose their jobs.”

Local officials agree, echoing the company line. “If it were possible to stop the smoke and keep all of our jobs, why not? But it isn’t,” said South Bay Mayor Joe Kyles.

South Bay Mayor Joe Kyles stands in front of sugar cane fields, with smoke visible in the distance.
South Bay Mayor Joe Kyles watches a cane burn in the distance while attending a food distribution event at a local church. A U.S. Sugar ballcap shields his face from the sun. Photo by Thomas Cordy, The Palm Beach Post.

While American sugar executives argue they can’t overhaul their processes, the country is an outlier on the global stage. The U.S. is the fourth-largest sugar producer in the world. China is the only other top five sugar-producing country that hasn’t moved to end cane burning.

In the last decade and a half, the three other top sugar-producing countries have turned away from burning as researchers and public officials raised concerns about a specific byproduct of the practice: fine particulate matter, or PM2.5. The toxins are so tiny — 1/30 the width of a human hair — they can be easily inhaled, inflaming the throat on their way to the lungs, and in some cases making their way into the bloodstream.

In 2007, researchers in Brazil, the world leader in sugar production, found links between exposure to smoke from cane fields and increased hospitalizations for asthma. Officials responded to pollution concerns with a plan to completely stop burning and instead remove cane leaves with blades before harvesting the sugar. Brazil still burns cane today with plans to phase the practice out within a decade.

Likewise, Thailand has restricted burning while transitioning to a total ban within the next two years. One study estimated it will cost growers between $3 and $6 more per ton of sugar to harvest cane without torching it. In May, Vietnamese news publications reported that Thailand’s cabinet approved a $192 million subsidy program to aid farmers in the transition after complaints from growers about the financial impact. Some farmers defied the burn ban by burning their fields at night, Thai media reported.

India, the second-largest producer of sugar, already has banned and criminalized crop burning. Officials there have fined and even arrested some who have violated the ban, according to Indian media reports.

Florida Crystals said that South Florida shouldn’t be compared to foreign countries, noting that the farming practices, soil and weather conditions, and regulations in those places differ. The company also noted the large role that government subsidies played in the transition away from burning elsewhere.

Even in the U.S., however, sugar interests in one state — Louisiana — have made changes. Farmers there tweaked their burning practices in the mid-1990s, after state regulators pressed for change in response to hundreds of complaints from residents each year about smoke. Instead of burning the cane while it stands in the field, as farmers do in Florida, most Louisiana farmers now cut the cane before burning it, said Joey Breaux, an assistant commissioner at the state agriculture department.

This post-harvest burning produces a less intense fire and, in turn, less smoke and soot, which led to fewer complaints, Breaux said. Because Louisiana doesn’t track individual field burns the way Florida does, it’s difficult to verify the pollution impacts in Louisiana and compare the two states. In interviews, Louisiana officials said the agriculture department had seen a steep drop in complaints since the mid-1990s. When asked for any complaints made about cane burning since 2015, Louisiana agriculture officials provided just eight.

In the same decade that Louisiana was taking action, the federal EPA became increasingly concerned about particulate matter. Mounting research tied PM2.5 to heart and lung disease, asthma and premature death.

A group of young men walk on a road in front of a sugar cane field, with a tractor driving in the background. The air is hazy with smoke.
Young men walk near a burning cane field, looking for rabbits to chase down. For some families in the Glades, selling rabbit meat is their only source of income. Photo by Thomas Cordy, The Palm Beach Post.

In 1997, the EPA set national air-quality standards that aim to reduce exposure enough to protect public health. Regulators charged individual states with monitoring the air.

In Florida, that task falls to the state Department of Environmental Protection, which measures PM2.5 and other toxins using a network of air monitors — equipment owned and operated by local health departments. The state, in turn, sends that data back to the EPA, where federal officials determine potential violations.

This diagram shows a map of the Glades area, highlighting the cities of Belle Glade and Royal Palm Beach. The two cities both have air monitors, but are about 30 miles apart.
The state operates one air monitor in the Glades sugar-growing region. The next-closest monitor is to the east, in Royal Palm Beach.

But across 400,000 acres of sugar crops that span three counties, there is only one monitor, in Belle Glade. Tucked in a government complex next to the local free clinic and jail, the air monitor was flagged eight years ago because it wasn’t fit to enforce EPA standards. By comparison, the rest of Palm Beach County has three monitors, all situated in suburban neighborhoods or cities, all recording data to enforce those standards. That’s because under the Clean Air Act, population is a main factor in deciding where to place monitors. Environmental regulators originally designed the rules to protect large populations from industrial pollution.

That has left rural areas like the Glades with far fewer monitors — and has left swaths of the country with no oversight at all. More than 65% of counties across the country do not have an EPA monitor, which can cost between $10,000 and $35,000 depending on the model. The agency is looking into ways to improve air-quality oversight in rural areas, including places with agricultural burning, an agency spokesperson said.

At least at first, the state intended the Belle Glade monitor to be used to assess EPA compliance. Florida installed the Belle Glade monitor in 2009. Within four years, though, state officials noticed something odd. Officials used two monitoring methods at the Belle Glade site to gauge the accuracy of the monitor’s pollution measurements — a normal practice for air-monitoring agencies. The pollution measurements between the two differed by 23% to 43%, with each monitoring method producing both lower and higher measurements at times, well outside the requirements needed to meet the EPA’s strict quality standards.

The next-closest monitor, about 30 miles east in Royal Palm Beach, just outside the sugar region, also produced suspect readings.

In separate records obtained by the news outlets, the Florida Department of Environmental Protection wrote to the EPA to ask the federal agency to remove both air monitors from its national network, which the EPA uses for enforcing federal law. The EPA approved the removal, meaning federal officials could no longer use the monitor to hold polluters accountable if they found Clean Air Act violations.

Some states, after spotting a problem, will go beyond what’s required by federal law by replacing monitors, adding more monitors or adopting modeling to collect better data. In California, for example, officials deployed portable PM2.5 monitors during wildfires last year to enhance pollution monitoring.

And in other places, because of population growth, the state is required to replace the monitor; that’s what happened with Florida’s Royal Palm Beach monitor in 2017, according to a Department of Environmental Protection report that year.

But the original Belle Glade monitor, the one best positioned to capture agricultural pollution, remained, as of last week.

Alexandra Kuchta, a spokesperson for the state’s Department of Environmental Protection, defended the monitor, saying it wasn’t intended to provide data to enforce the Clean Air Act. Instead, it is used to provide more general information about where air falls on the Air Quality Index, a tool that broadly tells the public whether the air is good, unhealthy or hazardous. The AQI is fueled by monitors that do not have to meet the EPA’s strict accuracy standards.

Academic studies and news reports, however, have questioned the AQI’s ability to accurately gauge pollution risks. For example, a Reuters report last year highlighted a Philadelphia oil refinery explosion; the AQI showed that day as one of the year’s cleanest in the city, despite the refinery owner reporting that the blast had released large amounts of hazardous chemicals.

Florida’s use of the monitor is concerning, said Ricardo Cisneros, an environmental health professor at University of California, Merced and expert on air quality monitoring. He pointed out that the same model of monitor is used by California officials and is usually known for producing very accurate pollution readings — making the Belle Glade monitor’s discrepancies especially worrisome.

“You have data now saying you have an instrument that is not working properly,” said Cisneros, who reviewed state documents describing the monitor’s problems at the request of The Post and ProPublica. “I would question its validity.”

After the news outlets started asking questions about the Belle Glade air monitor, Kuchta, the Department of Environmental Protection spokesperson, said in January that Palm Beach County, whose department of health owns the equipment, plans to replace the monitor “in the future.” The new monitor, which a June 29 department report said was expected to be installed this month, will meet the EPA’s standards, she added. The Palm Beach County Department of Health would not respond to any questions for this story.

This map shows the locations of PurpleAir sensors, represented by yellow dots. The sensors, both placed in the city of Pahokee, are much closer together than the state air monitors shown in the previous diagram. This image also shows photos of the sensors at the bottom.
The Post and ProPublica analyzed data from low-cost air sensors placed at two homes in Pahokee during the cane-burning season.

In addition to sparse monitoring in rural areas, experts have identified other gaps in the regulatory system that leave communities like the Glades vulnerable. Chief among them is how the EPA measures particulate matter. Officials use 24-hour and annual averages to determine whether the air is safe. The metrics were designed to capture long-running sources of pollution. That means that short-term pollution — like the smoke from sugar cane burns, which usually last less than an hour — can fly under the radar.

On paper, areas with bursts of pollution but otherwise clean air average out to normal levels.

“The thing that the standards are not very good at protecting is these localized exposures,” said Dr. Mark Frampton, a pulmonologist at the University of Rochester who served on the EPA’s Clean Air Scientific Advisory Committee, the team tasked with assessing the nation’s standards for this type of pollution.

To get a better sense of what Glades residents were experiencing in real time, The Post and ProPublica consulted with a panel of six air-quality experts, five of whom have used low-cost sensors to track air quality elsewhere in the country. With their guidance, the news organizations placed three such sensors, made by Utah-based PurpleAir, outside homes in Pahokee during the cane-burning season. Two of the sensors collected data for four months. A third sensor experienced technical issues, so the news organizations omitted it from the analysis.

The news organizations found sensor hosts through an outreach campaign that included mailing letters to area teachers, knocking on doors to distribute flyers and calling registered voters. None of the sensor hosts are part of the ongoing legal challenge or affiliated with environmental groups.

This gallery of two images shows a couple outside of their home, and zooms in on a purple air sensor attached to the outer wall. The sensor is a small, white, metal container hanging from a hook.
Jose and Sandra Fonseca in front of their home with a PurpleAir sensor provided by The Post and ProPublica. The sensor collected real-time air-pollution data for four months. Photos by Thomas Cordy, The Palm Beach Post.

Jose Fonseca, a parks worker who grew up in the Glades, was among those who hosted a sensor. He doesn’t have any major health problems but often experiences coughing fits when he’s outdoors during cane season. His mom, Sandra, also struggles to breathe when there’s smoke outside.

“People say that it’s unhealthy and we see the smoke, we smell it, but I wanted to know how much of that we’re exposed to,” Fonseca said.

To be sure, the low-cost sensors aren’t as precise as the pricier equipment used by the federal and state governments, and research shows they tend to give higher readouts. The sensor readings, however, can be corrected using an EPA formula.

PurpleAir sensors are among the most accurate low-cost air sensors on the market, according to studies by the South Coast Air Quality Management District, the largest air-quality agency in Southern California, where officials are battling some of the poorest air quality in the nation.

In fact, the EPA deploys the same PurpleAir sensors to communities as part of air-testing programs in the Midwest, California and tribal communities in the Northwest. These efforts have helped the EPA get a more complete understanding of air quality across regions, an EPA spokesperson said, adding that the agency considered the programs a success.

Experts advised The Post and ProPublica to use the Glades sensors to gauge real-time changes in air pollution, not to compare exact measurements to Clean Air Act standards.

Data from these sensors appeared to back up what residents often described during burn season: smoke from cane burns reaching neighborhoods intermittently.

This diagram shows a line chart displaying PM2.5 levels on Dec. 21. The line is fairly even at low pollution levels, with a few scattered increases.
Our two sensors in Pahokee measured air pollution in real time for four months. This is what the average PM2.5 levels looked like on Dec. 21. Even though about 1,400 acres were burned, projections showed that the smoke would blow away from Pahokee. The sensor report was relatively calm.
This line chart from Feb. 18 shows more spikes in PM2.5 readings, representing higher air pollution.
These are the PM2.5 levels from Feb. 18. On this day, roughly 1,800 acres were burned and the smoke was projected to blow toward Pahokee. The sensors picked up on air pollution in the morning and afternoon.
This graphic includes two line charts, showing the difference between PM2.5 levels when smoke is projected to blow towards Pahokee versus when it's projected to blow away. In the former scenario, there are high PM2.5 levels and many spikes; the latter is calmer.
Since PM2.5 can also come from sources like cars and wildfires, it is tough to tie these spikes to cane burning specifically. But our analysis of more than 100 days of data found repeated spikes in PM2.5 on days when the state authorized cane burns and projected smoke would blow toward instead of away from town.
This chart zooms in on PM2.5 patterns on days when smoke is projected to blow towards Pahokee. The chart highlights pollution spikes with light silver boxes overlaid over the yellow lines.
Spikes often reached four times the average pollution level in the area. The sensors also reported more spikes in PM2.5 between 9 a.m. and 8 p.m. — the hours when cane is burned and the resulting smoke may linger. These findings strongly suggest a link between air pollution and cane burning, said Christopher Holmes, a Florida State University professor who reviewed the news organizations’ findings.
The same chart, displaying PM2.5 patterns on days when smoke is projected to blow into Pahokee, is now all highlighted with a yellow background.
A growing body of research shows that any level of PM2.5 can be harmful, but it’s difficult to know the precise health impact of exposure to these short bursts of air pollution. While the World Health Organization says PM2.5 should not exceed 25 micrograms per cubic meter over 24 hours, there is no standard for exposures lasting less than an hour.

Sugar companies challenged The Post and ProPublica’s analysis because it is based on pollution measured in 10-minute intervals, rather than the 24-hour averages that state and federal officials use. The companies added that the Belle Glade monitor hadn’t registered PM2.5 levels that exceed 24-hour federal standards, though the EPA says that monitor couldn’t be used to make such determinations.

The news organizations measured shorter intervals because individual cane fires generally last less than an hour. Experts said that short spikes in pollution might not appear in 24-hour averages — which include about 13 hours a day when cane burning doesn’t take place and spikes in pollution are rarely recorded.

Sheryl Magzamen, a Colorado State University professor who studies the health impact of exposure to environmental toxins and reviewed the news organizations’ analysis, said the short bursts of PM2.5 recorded by the PurpleAir sensors in the Glades can have immediate health effects.

“We’ve seen that spikes in air pollution, even short-term changes, had meaningful impacts on inhaler use, which we take to be signs of asthma and COPD [chronic obstructive pulmonary disease] exacerbation,” she said, referring to her past research. “It shouldn’t be surprising to us that inhaling smoke is bad for you.”

Magzamen, who spoke regularly with The Post and ProPublica over the past year, submitted a grant proposal to NASA to expand on the media outlets’ research. She aims to partner with academics and community leaders to deploy a larger network of sensors across Florida’s sugar-growing region, examine satellite data and analyze health trends — actions the state has never taken.

“Everyone has kind of said, ‘Why aren’t we studying this?’” she said. “These exposures are here, in our communities, and nobody is doing anything about it.”

Christopher Holmes, a Florida State University professor and expert in air quality monitoring, said The Post and ProPublica’s analysis highlights a need for more scrutiny. With better equipment and data, government agencies can examine whether spikes in pollution are directly tied to the smoke and assess the health impact on residents, he said.

To get a sense of what Glades residents experienced, The Post and ProPublica deployed automated text messages to 51 residents across the region in the moments after the low-cost sensors picked up spikes in pollution. (To find participants, the outlets called every sixth person in the area’s voter rolls, knocked on doors in Glades neighborhoods and handed out flyers at food banks.)

Some described coughing, itchy eyes and trouble breathing. Others simply described the smell of the smoke or shared pictures.

Many who replied opted to stay anonymous, some citing fear of repercussions in a town reliant on sugar companies. “Ash everywhere hard breathing,” a former U.S. Sugar mill worker with severe asthma replied during a spike. He asked that his name not be used for fear of losing retirement benefits.

Health and air-quality researchers said some of the symptoms residents say they experienced align with elevated exposure to PM2.5.

“I’m not surprised that there would be effects even with shorter-term exposure, especially if the exposures are repeated and recurrent,” said Frampton, the pulmonologist and former EPA adviser. “If you have asthma, that can trigger immediate effects. It doesn’t have to be around for very long at all.”

2020 EPA rule proposal, citing research on pollution and health impacts, notes that exposure to high levels of PM2.5 lasting less than one hour can impair heart function, promote clot formation and increase blood pressure. The report adds that studies have linked mortality to daily exposures below the federal 24-hour standard. The EPA is currently reassessing that standard.

For other pollutants, health effects related to short-term exposure have moved the EPA to create standards for shorter durations, such as every hour or every five minutes. While that could be an option here, some experts warn that monitoring particulate matter the same way could present enforcement problems. For example, Frampton said, with shorter averages, local governments run the risk of violating the Clean Air Act every time there’s a single burst of pollution, like a house fire.

Even so, he added, that doesn’t dismiss the need for state regulators to step in and address recurring short-term pollution like cane burning in rural areas.

“Do some monitoring, demonstrate that people are getting exposed to something that’s in the range that’s known to cause adverse health effects, and then do something about that local situation,” he said.

A man dressed in a suit stands in front of a blue banner reading, "Drop The Cane Burn Suit."
Local clergy joined citizens and mayors from Clewiston, South Bay and Belle Glade to voice their support for the sugar industry, which faces a federal lawsuit. Pastor Robert Rease of Belle Glade spoke at the press conference in October. Photo by Thomas Cordy, The Palm Beach Post.

For now, 10 Glades residents are pressing their case in federal court. The complaint claims sugar cane companies were negligent in burning cane and spilling ash into the community, despite the fact that alternatives exist.

The residents are also asking the court to force sugar companies to pay for annual lung cancer screenings, citing research by the World Health Organization that has linked the illness to the same pollutants produced by cane burning. The suit seeks class-action status on behalf of thousands living near cane fields.

But as the case worked its way through the court system, lawmakers passed a measure in April to expand the state’s Right to Farm Act, which aims to protect farmers from so-called nuisance lawsuits, typically filed by neighbors seeking to curb odors, noise and other side effects of farming. At first, the Right to Farm laws were a response to urban sprawl in the 1970s and 1980s, when several states moved to protect farmers from development that drew closer to rural areas and exposed farmers to lawsuits over practices that predated suburban growth. The laws have since been expanded to shield a range of farming and ranching practices from legal scrutiny.

Sponsors of the legislation insisted that it wouldn’t affect the pending lawsuit in the Glades. But while sugar cane burning wasn’t mentioned in the Florida legislation, lawmakers did add “particle emissions” to the list of protected farming operations, creating a hurdle for those seeking to sue farmers over air pollution in the future. DeSantis signed the legislation into law.

That means the current case may be the last in Florida to consider pollution from cane burning as a central issue. The case hinges on the question of air quality, said Matthew Moore, the chief lawyer for Glades residents. Lawyers from Boca Raton-based Berman Law Group, Moore’s firm, hired an environmental engineer who used air modeling estimates that suggested pollution emissions were higher than those recorded by the state-run Belle Glade monitor, legal filings show.

In a motion to dismiss the case, sugar companies cited readings from the Belle Glade monitor to write that pollution concentrations “were well within NAAQS,” or the standards in the Clean Air Act, even though the monitor couldn’t be used to determine that. The motion to dismiss added in its criticism that the complainants didn’t “perform any monitoring of their own.”

Last week, a federal judge ruled that the case should move forward on negligence, pollution discharge and health-monitoring claims. He dismissed two of the plaintiffs’ other claims alleging battery and civil rights violations. Previously, the judge dismissed a nuisance claim, among others.

Meanwhile, environmental groups are calling on the state to step up its monitoring. The Sierra Club released a study in May, headed by a Ohio-based Miami University researcher, that found that the single monitor in Belle Glade cannot capture smoke pollution across the region. Environmentalists and residents leaned on the report to push for better air monitoring and no-burn buffer zones near towns.

For now, residents like Otishia Harvey live with the burning.

An elementary school teacher, Harvey has spent most of her life in the Glades, raising five children in her Pahokee home. She developed asthma as an adult and regularly wakes up with attacks so severe, she can’t move. Three years ago, after her first severe asthma attack, she taught her then-5-year-old son, Zaiden, how to squeeze steroid drops into tubes that connect a medical mask to Harvey’s nebulizer, a device the size of a lunchbox. Zaiden would place the mask on his mom’s face and wait by her bedside until her heavy breathing slowed.

A young boy stands in front of a blank background, holding a nebulizer mask.
Otishia Harvey’s son Zaiden prepares a nebulizer treatment for his mother at their home in Pahokee. Photo by Thomas Cordy, The Palm Beach Post.

Now, she navigates around the sugar cane burns, avoiding the outdoors when she can.

“Breathing is the most normal thing you can do. It’s the most effortless thing,” she said. “And it’s to the point where if I don’t take the asthma medication, it feels like I’m going to die.”

After an intense asthma attack in October, she said her doctor told her she should leave the Glades if she ever wants her breathing to improve.

“It isn’t fair,” Harvey said. “I’m like most people here. We can’t leave.”

A woman sits on the right side of the photo, wearing the same nebulizer mask from the previous image. She's in front of a blank wall, and a television sits on the floor on the left side of the photo. The woman is wearing a pink T-shirt reading, "FIGHT FIGHT FIGHT FIGHT FIGHT."
Otishia Harvey sits with her nebulizer at her home in Pahokee. Photo by Thomas Cordy, The Palm Beach Post.

Methodology: ProPublica and The Palm Beach Post analyzed sugar cane burn permit data and PM2.5 readings from Dec. 10, 2020, to April 4, 2021. The permit data was provided by the Florida Department of Agriculture and Consumer Services, and we filtered the records down to burns originating in Palm Beach County. PM2.5 readings were collected from three PurpleAir outdoor air sensors placed at residences in Pahokee, Florida. The burn season was ongoing during the entire time period the air sensors were collecting data. Data from one sensor was omitted entirely from the analysis because it did not meet the quality assurance standards described below.

PM2.5 Analysis: PurpleAir sensors are low-cost air-quality sensors that provide real-time measurement of fine particle pollution, including PM2.5. PurpleAirs are not regulatory-grade monitors, but they are useful in monitoring rapidly changing air quality in local contexts when raw output values are adjusted.

PurpleAir sensors consistently overestimate PM2.5, according to results from a nationwide study by the EPA. To address this, the EPA developed a formula that adjusts PurpleAir sensor data using relative humidity and other correction factors. At this time, the agency has tested the formula mainly under wildfire conditions, and continues to refine it.

We averaged raw data using 10-minute intervals and then omitted points that had a greater than 70% difference between channels as part of a quality assurance method recommended by EPA researchers. We then used the EPA’s formula to adjust the data and then averaged the results across both sensors. We chose to calculate averages over 10-minute intervals because cane burns typically last roughly 15 to 40 minutes.

We looked at sensor data between 9 a.m. and 8 p.m. because that is the authorized window for burning. Burns are generally permitted between 9 a.m. and one hour before sunset (roughly 6 p.m.) for noncertified burners and two hours after sunset for certified burners. Experts advised that we should include a buffer for allowing smoke to disperse into communities.

Burn Permit Analysis: The burn permit data provided by the state contained a location and a modeled smoke plume for each authorized burn.

To determine whether smoke was likely blowing toward Pahokee or not, we categorized each day into one of two categories:

  • “Toward Pahokee”: At least one sugar cane smoke plume that day had potential to be blown toward the sensors located in Pahokee.
  • “Away from Pahokee”: All sugar cane smoke plumes were unlikely to be blown toward the sensors.

Assuming that plumes might disperse somewhat farther than their modeled boundaries, a burn was categorized as “toward Pahokee” if at least one of the following conditions was met. Burns that met none of the following conditions were categorized as “away from Pahokee”:

  • Its plume’s projected boundaries were within a 2.5-mile radius of the Pahokee sensors.
  • Its plume was pointed within 15 degrees of Pahokee, even if the projected boundaries did not intersect with a 2.5-mile radius around Pahokee.
  • Its plume was wider than 150 degrees (indicating variable winds) and the burn was less than 10 miles away from Pahokee.

If any of the burns that day fell into the “toward Pahokee” category, we categorized that day as “toward.” If none of the burns that day fell into the “toward” category, we categorized that day as “away from Pahokee.”

Data Quality and Limitations: In analyzing burn permits, we confirmed with the Florida Department of Agriculture which permits were canceled, leaving only those that were authorized. Though the department has no mechanism for confirming that each burn ultimately took place, it said requesters generally cancel permits or indicate a change in acreage to 0 or 1 if they do not burn the field.

Burn-permit data was missing or likely incomplete on a handful of days. The Florida Department of Agriculture said its server was down on occasion, but could not specify which days or times across the entire time period. We therefore omitted days from our analysis that had unusually low burn counts of fewer than 3. We also omitted permits that listed an acreage of 0 or 1. The Department of Agriculture said these burns were authorized but not ultimately conducted.

One sensor also reported an anomalously high raw value of roughly 1,800 micrograms per cubic meter on Feb. 20, which we omitted from our analysis.

The following air-quality experts guided The Post and ProPublica in planning our sensor effort and analyzing our data: Christopher Holmes, Florida State University; Ricardo Cisneros, University of California, Merced; Sheryl Magzamen, Colorado State University; Darby Jack, Columbia University. Two additional academics from Florida universities guided The Post and ProPublica in the analysis. They asked not to be named because of university policies.

Credits: Lulu Ramadan is an investigative reporter at The Palm Beach Post. Ash Ngu is a reporter, designer and developer with ProPublica’s news apps team. Maya Miller is an engagement reporter with ProPublica focusing on health, environment and housing. Al Shaw and Erin Smith contributed reporting to this story. Photography by Thomas Cordy with The Palm Beach Post. Videography by Greg Lovett with The Palm Beach Post. Additional contributions by Sally Beauvais, Jan Byun, Adriana Gallardo, Maryam Jameel, Ryan Little, Beena Raghavendran, Ariana Tobin, Kengo Tsutsumi.

You may view this story in its original format at ProPublica.