As It Turns Out, Louisville’s Particle Air Pollution Was As Bad As The EPA Thought
Jefferson County is one of more than 50 counties across the country that failed to meet federal health standards for fine particle pollution from 2011 to 2013, but was misclassified by the Environmental Protection Agency, according to a new study released in September.
The study from nonprofit Resources for the Future mapped fine particle pollution across the country to look at the difference between what the EPA rated as meeting the health standard and what researchers could find using high-resolution satellite data.
The purpose was to measure how many people live in areas where pollution levels are high, but go undetected by air-quality monitors. In total, they found more than 1.2 million people in Kentucky lived in counties misclassified by the EPA.
Across the country, only about one in five counties monitor fine particle pollution. Of those, less than half have just one monitor, according to the study. That makes it difficult for researchers to track air pollution and exposure.
“So all of these problems are mitigated, if not solved, mitigated by the satellite data,” said Daniel Sullivan, co-author of the study. “It’s a sanity check, it’s a peak at the other player’s battleship board.”
Kentucky environmental quality officials are less convinced. The study is scientifically valid, but doesn’t provide the precise, quality-assured data needed to evaluate federal health standards, said Kentucky Department of Environmental Protection Deputy Commissioner Sean Alteri.
“I think there is merit in those principles, however I don’t believe that this study accurately characterizes the air quality in Louisville in particular, and throughout the state,” said Alteri, who formerly lead the Division of Air Quality.
Air quality monitors are essential for observing fine particle pollution. At 2.5 microns, the particles are one-twentieth the diameter of a human hair — though they can be even tinier. Fine particle pollution is in car exhaust, emissions from power plants and factories, dust from construction, demolition and mining and much, much more.
Every day researchers are learning more about the adverse health impacts of breathing in these fine particles. Already, year-round exposure is linked to increased risk of asthma, heart disease, lower birth weight and infant mortalities, according to the American Lung Association.
Other studies cited by the group have found that long-term exposure may increase the risk of developing type 2 diabetes while recent research from Arizona State University finds it may even increase the chances of dementia.
The Resources for the Future study found people living in misclassified counties are seeing fewer improvements in air quality. As a result, Sullivan estimates improved air quality may have prevented 5,452 premature deaths in misidentified counties across the country.
“If your county is flagged as being in attainment with the Clean Air Act, it doesn’t necessarily mean it’s an area with clean air,” Sullivan said.
The impact of Louisville’s misclassification is less clear.
Satellite data found a significant portion of the Louisville-Metro area exceeded health standards for fine particle pollution from 2011 to 2013, but long-term trends show Louisville has made significant strides in reducing fine particle pollution.
Louisville’s Incomplete Data
Louisville is keenly aware of the risks posed by air pollution. Smoke from burning coal that heated homes and generated electricity blanketed the city in black soot through both world wars.
In 1945, the city created the Louisville Smoke Commission to address the city’s soot, smog and smoke.
That tradition continues today under the Air Pollution Control District – renowned for reducing toxic emissions from large industries through the 2005 STAR program.
Unlike other cities in the study, Louisville currently has 10 air-quality monitors measuring different aspects of the pollution, said Billy DeWitt, air monitoring program manager with Louisville’s Air Pollution Control District.
“We measure pm 2.5 every hour, every day,” DeWitt said.
But in 2013, when federal standards changed, the EPA didn’t use any of Louisville’s air quality monitors to measure the city’s fine particle pollution.
That’s because multiple audits found failures in the lab at the Air Pollution Control District. The EPA disqualified years of air quality data. The void left little reliable data for EPA regulators to interpret.
The EPA instead looked at air quality monitors across the river in Indiana. Those, too, indicated Louisville wasn’t meeting the health standard and in January 2015 the EPA ruled the city was in “nonattainment.”
But the EPA reversed its decision. After a review of supplementary data early certified by Indiana, the EPA officially changed the city’s status in April 2015 to “unclassifiable,” a reflection of Louisville’s incomplete data.
What The Study Found
The Resources for the Future study offers a second chance to revisit those decisions.
Researchers found that much of the Louisville-Metro area exceeded health standards for fine particle pollution from 2011 to 2013. Bullitt, Campbell, Daviess, Henderson and Kenton counties also exceeded EPA standards, according to the study.
Researchers used satellites to capture data on the density of airborne particles by measuring aerosol optical depth.
They compared the intensity of solar radiation at the top of the atmosphere with the amount of radiation reflected off the earth’s surface. The more fine particle pollution there is, the less radiation is reflected back at the satellite, according to the study.
Louisville’s Air Pollution Control District agreed the satellite data was actually very close to what APCD was seeing at the time.
“Our ground-based monitors indicated nearly the same thing for that time period,” DeWitt said.
The study's methods do have drawbacks though. They don’t measure fine particle pollution directly and they can’t measure conditions near the ground on cloudy days so they make up for it by collecting data over months and years.
DeWitt says ground-based monitors remain the best way to measure fine particle pollution.
“[The satellite instruments] are calibrated using the ground-based monitors, so it looks like the ground-based monitors are still the standard at this point,” DeWitt said.
Where Are We Now?
Resources for the Future estimates misclassified counties including Louisville experienced a 3.9 percent increase in deaths in areas where fine particle pollution was above EPA’s health standard, and a smaller increase in mortality for the rest of the affected county.
But there’s also evidence Louisville might be an exception to the study’s estimates.
The study assumes that misclassified counties don’t see the same average decline in pollution levels because regulators are not required to develop plans to reduce emissions.
Louisville, however, has seen a steady decline in fine particle pollution for more than a decade, according to Air Pollution Control District data. Among the largest contributing factors, are changes in the county’s power plants.
First, Louisville Gas and Electric added pollution control devices to the Mill Creek coal-fired power plant, which reduced harmful pollutants including sulfur dioxide in addition to reducing fine particle pollution.
Then, in 2015, LG&E closed the coal-fired power plant at Cane Run and switched to natural gas, which burns significantly cleaner than coal.
In August, the EPA announced the Louisville area — which includes Jefferson and northern Bullitt counties — is meeting air quality standards for fine particle pollution.
“Air quality in Kentucky is improving, and across the nation dramatically,” said Alteri, with the Department of Environmental Protection. “And [fine particle pollution] levels have decreased significantly in the last 10 years.”
This story has been updated.