A lapse in federal government oversight during shutdowns corresponds with a significant increase in air pollution from coal-fired power plants, according to a recent study. Researchers found that when federal employees are furloughed and enforcement activities are paused, emissions of harmful particulate matter rise, suggesting that regulatory oversight is a crucial, active deterrent against the release of certain pollutants into the atmosphere.
Using the 35-day U.S. government shutdown of 2018–2019 as a natural experiment, a team of economists and environmental researchers analyzed daily emissions data from nearly 200 power plants. They discovered that while some pollutant levels remained stable, the concentration of atmospheric soot, or particulate matter, increased measurably. The findings, published in the Journal of the Association of Environmental and Resource Economists, indicate that power plant operators may strategically alter their operations and reduce pollution control efforts in immediate response to a known pause in federal inspections and enforcement.
A Natural Experiment in Emissions
The extended shutdown at the end of 2018 and into 2019 provided a unique opportunity for researchers to isolate the effect of federal enforcement on environmental compliance. For 35 days, a significant portion of the U.S. Environmental Protection Agency’s (EPA) staff was furloughed, effectively halting routine inspections and compliance monitoring activities across the country. This created a clear before-and-after scenario to assess how industrial facilities behave when the primary environmental regulator is temporarily offline.
The 2018–2019 Shutdown Case Study
Lead author Ruohao Zhang, an assistant professor at Penn State, and his colleagues treated the shutdown as a real-world test of regulatory impact. By comparing daily operations and emissions from coal-fired power plants just before the shutdown to their behavior during the furlough period, the team could identify short-term changes directly attributable to the absence of regulatory pressure. The study focused on a large sample of plants, providing a comprehensive view of the power sector’s response. The core question was whether the day-to-day threat of inspections, fines, or other enforcement actions actively incentivizes companies to keep pollution levels down.
The Particulate Matter Anomaly
The study produced a striking result: while emissions of sulfur dioxide and nitrogen oxides did not change, emissions of particulate matter rose significantly. This disparity was not random but was instead tied directly to how each pollutant is monitored by the EPA. The different outcomes for different pollutants provided strong evidence that the plants’ behavior was a calculated response based on their knowledge of the regulatory system and its temporary weaknesses.
Why Soot Increased but Other Pollutants Did Not
The key to the discrepancy lies in technology and procedure. Since 1995, the EPA’s Clean Air Markets Division has used a continuous emissions monitoring system for pollutants like sulfur dioxide and nitrogen oxides. These systems are typically installed directly within a power plant’s smokestacks and automatically transmit data to the agency around the clock, regardless of whether government employees are at their desks. Power plant operators know this monitoring is constant and automated, leaving no room to emit excess pollutants without detection. Therefore, emissions of these gases remained flat during the shutdown.
In contrast, monitoring for particulate matter is often more labor-intensive. The EPA relies on a network of over 1,200 sites across the country where filters collect ambient air samples. These filters must be physically collected and analyzed by personnel. When EPA enforcement staff are furloughed, these activities stop. Operators are aware that this crucial part of the enforcement chain is broken during a shutdown, creating an opportunity to scale back costly pollution control measures, such as electrostatic precipitators or baghouses that capture soot before it is released.
Quantifying the Pollution Spike
The increase in particulate matter was not trivial. The research shows that during the 35-day shutdown, particulate matter pollution from the studied coal plants increased by an average of 15 to 19 percent. This demonstrates a rapid change in operational behavior, occurring within days of the EPA furlough taking effect. The researchers also analyzed a related atmospheric measure called aerosol optical depth, which measures the concentration of tiny solid particles and liquid droplets suspended in the air.
They found that within a three-kilometer radius of the power plants, the aerosol optical depth increased by an average of 0.018 to 0.022. While the numbers seem small, they represent a significant increase over the typical U.S. average of 0.1 to 0.15, confirming a localized spike in airborne particulate matter surrounding the facilities. This data provides a secondary line of evidence supporting the primary finding that more soot was entering the atmosphere.
Enforcement as an Active Deterrent
The study’s authors conclude that the findings highlight the critical importance of active, consistent regulatory enforcement. The results suggest that for certain pollutants, compliance is not a passive, long-term state but an active, daily operational decision influenced by the perceived likelihood of getting caught. Co-author Neha Khanna, a professor at Binghamton University, noted that companies appeared to “strategically” sidestep environmental rules when they knew inspections were halted.
This implies that the mere existence of environmental laws is insufficient without the personnel and resources to enforce them. The threat of inspection appears to compel facilities to run their pollution-scrubbing technologies more rigorously or consistently. When that threat is removed, even temporarily, some operators may choose to reduce those efforts to save on operational costs, leading to immediate environmental consequences. The study underscores that budget cuts and furloughs at regulatory agencies are not just administrative issues but can have direct and measurable impacts on environmental quality.
Public Health and Policy Implications
An increase in particulate matter pollution, even for a short period, carries significant public health risks. These tiny particles, often 2.5 micrometers or less in diameter, can penetrate deep into the lungs and enter the bloodstream, contributing to respiratory and cardiovascular problems. Researchers noted that even minor increases in exposure to this type of pollution are linked to elevated mortality risks. Vulnerable groups, including children, the elderly, and individuals with preexisting health conditions living near these power plants, are at the highest risk.
The study’s authors propose that policymakers should focus on ensuring stable and continuous inspection and enforcement capacity to prevent such pollution spikes in the future. Recommendations include minimizing enforcement gaps and expanding the use of continuous, automated emissions monitoring for a wider range of pollutants, which would make the system less vulnerable to disruptions from government shutdowns or budget cuts. The research serves as a clear warning that interruptions in governance can undo the daily work of protecting air quality and public health.
