Environment

Louisville’s air quality officially met the national standard for sulfur dioxide this week for the first time since 2013, but it continues to struggle with unhealthy levels of ozone, according to the U.S. Environmental Protection Agency.

The designation comes about eight years’ after Louisville Gas & Electric invested nearly $1 billion in pollution controls at the Mill Creek coal-fired power plant — the county’s largest source of sulfur dioxide (SO2).

The EPA’s designation is evidence of Louisville’s improving air quality, but it also highlights the more stubborn challenge that remains: ozone. There is no one single source for the pollutants that make ozone, and it’s going to require broader community participation to meet the national standard.

Those are the results of a new report drafted by Louisville’s air quality regulator, the Air Pollution Control District, in coordination with more than three dozen local and national non-profits, businesses and other government agencies.

“There is no SO2 scrubber kind of magic solution,” said Michelle King, APCD Director of Program Planning. “Because there (are) just so many different sources and products that, that is something that is more of a challenge for us.”

Improving air quality plays a big role in human health. In fact, researchers studied this exact thing in Louisville and found 400 fewer hospital visits for asthma attacks in the year after LG&E added pollution controls on Mill Creek.

But while the benefits of improving air quality help everyone, the detriments of pollution, including ozone and SO2, disproportionately impact disadvantaged communities. For example, the 2017 Louisville Metro Health Equity Report found nearly double the rates of inpatient asthma admissions among the city’s Black residents.

“We all need to understand there are health impacts from ozone non-attainment,” King said. “In some ways it’s the underlying health conditions that can be exacerbated by the same air quality in two different neighborhoods.”

Ground level ozone forms when oxides of nitrogen (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. The hotter and drier it is, the more ozone is created. That’s why Louisville’s ozone season runs from March through October when the days are longer and warmer.

NOx is a side effect of combustion, which isn’t great for a society that still largely derives its energy from burning fossil fuels. LG&E’s Mill Creek and Trimble County coal-fired power plants are still the two largest industrial emitters of NOx, and industrial sources overall are largest contributors to NOx pollution in the city, but emissions from vehicles are another large contributor, according to APCD’s Multipollutant Stakeholder Report.

The planes at Louisville’s airport, cars and trucks also contribute to the VOCs in the air, but as a whole the area’s single largest emitters can be traced back to bourbon, King said. In 2017, the latest data available, Jim Beam’s Clermont plant had the highest emissions in the region, followed by Heaven Hill, Brown-Forman and Four Roses distilleries, according to the report.

The largest overall share of VOCs come from what are called non-point sources and include everything from body shops, to dry cleaning, to woodworking. Much of that is due to the use of solvents in industrial, commercial and residents cleaning products.

A study within APCD’s report concluded Louisville would see the largest ozone benefit by reducing NOx, though it also noted it would help Louisville’s urban core to reduce VOCs.

APCD brought together a coalition of more than three dozen organizations to help the city reach the national standard. The group included many of the largest emitters of the pollution that forms ozone. For example, LG&E, Brown-Forman, Heaven Hill and Kosmos Cement Company worked alongside government agencies and non-profits to come up with recommendations for how to improve the city’s air quality.

The recommendations are numerous. Here are a few: Start a list of planned pollution reductions from stakeholders, encourage action from large emitters on air quality alert days, encourage energy efficiency projects and technology improvements that limit pollution, and implement strategies to expand the use of electric vehicles and bicycles.

LG&E made a commitment even before the report was released. In April, the county’s electricity and natural gas provider agreed to reduce NOx emissions at its Mill Creek plant from a high of as much as 36 tons per day to at or below 15 tons per day during Louisville’s ozone season.

APCD has already begun sharing the report’s recommendations with Louisville Metro Government and the EPA, but many of the improvements will require broader community involvement, said King with APCD.

“Air quality is something we all own,” King said. “It goes from government and large industry all the way down to residents to really own air quality and understand why it’s so important.”

Ryan Van Velzer is WFPL's Energy and Environment Reporter.