This story is from Floodlight, a nonprofit newsroom that investigates the powers stalling climate action. Sign up for Floodlight’s newsletter here.
Across much of the U.S., people have little way to know when the air they breathe turns dangerous.
Over recent decades, federal funding for public air monitoring has declined, the number of monitors has fallen, and much of the remaining equipment is aging or located far from major polluters.
Now, the stakes are rising: Wildfire smoke is reaching more communities, data centers are adding pollution, and climate-driven heat waves are worsening ozone levels. The Trump administration, meanwhile, has delayed and rolled back requirements meant to hold companies accountable for their emissions.
As the public monitoring system has weakened, communities have increasingly turned to an alternative: low-cost sensors they can use themselves.
But a Floodlight investigation finds industry is moving to restrict that option, too.
Since 2024, lawmakers in Louisiana, Ohio and Kentucky have passed strikingly similar bills — backed by chemical or manufacturing trade groups — that curb the use of community-collected data in enforcement actions.
The bills share a common thread: They block regulators from using air-quality data for enforcement purposes unless it meets EPA-approved standards. Similar bills in West Virginia have yet to pass.
In case after case, proponents have made the same argument: Community monitoring isn’t reliable enough for regulatory enforcement.
Yet when lawmakers in West Virginia offered a version of a bill designed to ensure accuracy, industry resisted.
The bill “essentially codifies what we are trying to prevent,” an official at the chemical giant Chemours wrote in an internal email.
An early-warning system in decline
Thousands of small, often-unremarkable instruments serve as the nation's early-warning system for dangerous air — detecting pollution that people can’t always see or smell.
Some sit inside shelters the size of garden sheds. Others are mounted on rooftops or tucked into fenced compounds. Together, these monitors measure pollutants ranging from ozone and carbon monoxide to carcinogens such as benzene and vinyl chloride.
The network grew out of the 1963 Clean Air Act and transformed the way the nation tracked air pollution, giving regulators data they could use to identify dangerous conditions and hold polluters accountable. Since then, air pollution has fallen dramatically across much of the U.S.
But today, the network is “showing its age,” said Chet Wayland, who led EPA's Air Quality Assessment Division for nearly two decades. “And it's getting smaller over time.”
For example:
- Leaks, termites and ants plague monitoring stations in one state while officials in another have resorted to shopping on eBay for discontinued parts, according to a 2020 congressional watchdog report.
- Adjusted for inflation, federal grants to support the network have fallen more than 35% over the past two decades, while the Trump administration tried unsuccessfully last year to eliminate them entirely — and is trying again this year.
- The number of government air monitors nationwide fell by nearly half over the same 20-year period, according to EPA data.
The decline was especially pronounced among air monitors that track toxic chemicals, including those linked to cancer and other serious health effects.
For example, the network monitoring vinyl chloride — the carcinogen at the center of the 2023 train derailment in East Palestine, Ohio — shrank by more than half from 2004 to 2025. So did the network for chloroprene and benzene.
Floodlight analyzed the largest industrial sources of air pollution in Kentucky, Louisiana, Ohio and West Virginia — where the monitoring legislation was introduced — and compared what each one reported releasing against what public monitors in those states are capable of detecting.
For 71 of the 100 facilities examined, the chemical they release most isn't measured by any government monitor in the state.
Hydrochloric acid, sulfuric acid, methanol — no air monitor currently reporting to the EPA measures those toxic chemicals.
Nelson Roque, an assistant professor at Penn State, co-authored a 2025 study that found nearly six in 10 U.S. counties have no public air monitor at all.
Such gaps matter most in communities already facing higher risks. Black and low-income people bear a disproportionate share of elevated cancer risks from air toxics, according to the EPA.
“We've realized the value of other infrastructure, and yet not this one,” Roque said. “Last I checked, we all breathe air.”
The shrinking public network has set the stage for another fight: Who gets to measure the air, and whose data counts.
Louisiana: A monitoring gap, and the fight to keep it
Public air monitors in Louisiana — a national hub for oil, gas and petrochemicals — are often located miles from major industrial polluters and fail to test for some of the most dangerous chemicals, a recent Floodlight investigation found.
Community groups have tried to fill that gap. A $500,000 grant awarded under the Biden administration’s Inflation Reduction Act would have allowed the Louisiana Environmental Action Network to establish air monitoring in 27 communities it identified as pollution hot spots.
But the group was able to install monitors in only four communities before the Trump administration canceled the grant last year.
“It's like having your legs knocked out from under you,” said LEAN executive director Marylee Orr.
In 2024, meanwhile, Louisiana became the first state to restrict the use of community air monitoring data.
The Louisiana Chemistry Association helped draft the Community Air Monitoring Reliability Act (CAMRA), which cites the need for “science-based standards” and bars the use of air pollution data in enforcement or regulatory actions unless it’s captured by EPA-approved monitors. That equipment typically costs tens of thousands of dollars.
In a previous statement to Floodlight, LCA president David Cresson defended the law, saying it ensures “data used to enforce our state's environmental protection laws complies with minimum U.S. EPA standards” and doesn't stop residents from monitoring air quality for their own information — only from using unregulated methods for enforcement purposes.
The same period brought other rollbacks, some sought by the chemical industry’s most powerful national lobbying group. The American Chemistry Council — the LCA’s national counterpart — spent more than $22 million lobbying in 2024, ranking 10th among 9,200 organizations tracked by an independent watchdog group.
The ACC and the American Fuel & Petrochemical Manufacturers last year requested a blanket two-year exemption from Biden-era regulations meant to cut certain toxic emissions by nearly 80 percent at roughly 200 chemical manufacturing plants. They didn't get the blanket exemption — but individual plants that applied did.
So far, President Donald Trump’s EPA has granted more than 60 petrochemical facilities exemptions from the rule, and the agency is now weighing whether to rescind it entirely.
The ACC also successfully lobbied against federal rules that would have required about two dozen chemical plants to conduct fenceline monitoring for ethylene oxide, a carcinogen that contributes substantially to the elevated cancer risk in Louisiana's Cancer Alley.
The national trade group did not respond to Floodlight’s questions about its lobbying or its involvement in Louisiana’s CAMRA law. Nor did it explain its role in promoting similar legislation in other states.
But in an emailed statement, the ACC said it has invested in community air-monitoring projects and “publicly advocated for expanded access to credible air quality information.” It said it supports monitoring that produces reliable, transparent data and gives communities and regulators information they can use to make informed decisions.
Kentucky takes a page from Louisiana
Odors from Rubbertown, an industrial complex that housed tire and synthetic rubber plants during World War II, have long bothered residents in west Louisville, Ky. So, in the early 2000s, the city’s Air Pollution Control District, the EPA and others launched a study that confirmed what residents had long known: The air had unacceptably high levels of toxic pollutants.
A plan was enacted, regulations were revised, and the air was continuously tested. More than 15 years later, regulators announced toxic air contaminants in the Louisville metro area were down by almost 80 percent — with the most dangerous chemicals cut by 96 percent.
Despite the success of expanded air monitoring in Louisville, Kentucky lawmakers have moved in the opposite direction. In March 2025, 10 months after Louisiana’s CAMRA law, they passed House Bill 137, which also restricted how air-monitoring data can be used in enforcement actions.
Lloyd “Rusty” Cress, executive director of the Kentucky Chemical Council, told the Kentucky Lantern that the bill was similar to Louisiana’s community air monitoring legislation. The law says air needs to be tested with “scientifically defensible” methods — echoing a phrase used in an ACC blog post in 2023.
The ACC, the American Petroleum Institute, Dow Chemical and Chemours all lobbied for it.
Jess Loizeaux, a Chemours spokesperson, said the company doesn’t object to community air monitoring. “We object to community air monitoring results being used for enforcement decisions without first verifying the validity and accuracy of the data through official tests performed by trained technicians at the appropriate regulatory authority,” she told Floodlight.
Kentucky’s political push unfolded against a backdrop of major gaps in public air monitoring. Only one of the state’s 25 largest air polluters is close to an air monitoring station that measures the top toxic chemical it emits.
Fewer than a quarter of the state’s counties have an air monitoring station.
Ohio’s restrictions meet with legal challenge
Ohio’s new air monitoring rule was tucked into last year’s budget bill with no named sponsor. It, too, stops regulators from acting on air-monitoring data collected by community groups.
“When we take away the ability for those folks to have a reasonably priced monitor … for their own protection, we've just taken any tool they had right out of their hands,” said Miranda Leppla, an attorney who sued the state over the new rules last year on behalf of environmental groups.
The lawsuit also challenges another provision in the budget bill that instructs state regulators to remove Ohio’s “air nuisance rule,” which allowed citizens to take legal action against companies whose emissions endanger public health.
One of the plaintiffs, Donna Ballinger, lives in Middletown, Ohio, hundreds of feet from a steel manufacturing plant that frequently rains down black, white and gray particles onto her house and yard, she said. Fumes sometimes burn her eyes and throat, she said, and she often holds her nose when walking between her house and car.
“My fear is cancer,” Ballinger told Floodlight.
She has an air monitor mounted in her front yard. But Ohio’s new requirement has made it impossible to use the data such monitors collect “as evidence of the nuisance conditions,” the lawsuit says.
The Ohio Chemistry Technology Council backed the measure. The group did not respond to Floodlight’s requests for an interview.
Tony Long, general counsel for the Ohio Chamber of Commerce, said businesses are concerned that uncalibrated air monitors will spread misinformation.
“Given our litigious nature in this state, we think that the guardrails make sense,” he told Floodlight. “You don't want to be stopped for speeding on an uncalibrated speed gun.”
With more than 90 public air monitoring stations, Ohio has a more robust air monitoring network than some states. Yet none of Ohio's 25 largest air polluters are within 20 miles of a public air monitoring station that measures its top toxic emission. In fact, no air monitor in the U.S. measures the chemical that 10 of them release most.
Ohio’s Syensqo Specialty Polymers plant, which makes a resin used in plastics, released more than 130 tons of volatile organic compounds into the air last year.
The nearest air monitoring station is about four miles away — in West Virginia — and doesn’t measure VOCs.
Industry resistance stalls West Virginia efforts
West Virginia’s Department of Environmental Protection runs just 14 monitoring sites in 12 counties. The other 43 counties have no state monitoring stations at all.
None of West Virginia's 25 largest air polluters has a public air monitor within 25 miles that measures the pollutant it releases most. For 17 of the facilities, no air monitor anywhere in the U.S. measures their top toxic emission.
In 2024, a state bill backed by the West Virginia Manufacturers Association would have barred community air monitoring data from use in regulation, enforcement and lawsuits; it passed the House but died in the Senate — partly because industry couldn’t agree on what to include.
A compromise version of the 2024 bill, drafted to address the concerns of some lawmakers, would have let regulators use community data if the monitors met manufacturer standards. Industry refused to support it.
In emailed comments about the compromise bill, West Virginia Manufacturers Association Bill Bissett said it “neuters” the measure and was “now toothless.” Chemours’ Jeff Fritz wrote, “I do not like this draft,” and said the bill “essentially codifies what we are trying to prevent,” according to emails obtained by Mountain State Spotlight. Neither Bissett nor Fritz responded to requests for comment.
Subsequent bills, introduced in 2025 and 2026, also failed.
Why monitoring matters
Evidence shows that better monitoring can reduce pollution — and potentially save lives.
In 2018, the EPA made refineries begin monitoring benzene along their fencelines, and within five years, the number of refineries above EPA’s benzene action level dropped by half, according to a report by the Environmental Integrity Project.
While some states have made it difficult to know what’s in the air, others have been proactive:
- California is funding equipment and training for residents in fenceline communities to monitor for things like pesticides, hexavalent chromium and other toxic chemicals. From 2017 to 2025, the state budgeted $1.4 billion to help communities that have historically been overburdened with air pollution.
- Colorado required four industrial plants to install fenceline monitors that measure hydrogen sulfide, benzene and hydrogen cyanide in real time. The state also bought two mobile vans that regularly sample the same pollutants in surrounding neighborhoods.
- The Texas Commission on Environmental Quality and its contractors operate 33 automated gas chromatographs — sophisticated equipment that collects air samples every hour and provides near real-time readings of volatile organic compounds.
But in much of the U.S, those who live near industrial plants still have little way to know what they’re breathing.
An unanswered question
Reonda Victor lives in Louisiana's heavily industrialized corridor between Baton Rouge and New Orleans, where flares from industrial plants often illuminate the night sky.
Her mother, grandmother and sister all had breast cancer. Concerned about her own risk, she underwent genetic testing, which showed no predisposition to the disease, she said.
The closest public air monitoring station to her home — which lies in an area where air pollution poses one of the highest cancer risks in the country — tests only for lead.
Did industrial pollution cause the illnesses that struck her family members? She can’t say. But proper air monitoring could help answer that question, she said.
“Without information, we don’t know.”
Kentucky Public Radio contributed to this investigation.