Knox County Air Quality Improves

1/6/2017

The air you are breathing has become more breathable.

At least that’s the word from the Environmental Protection Agency, the Tennessee Department of Environment and Conservation and the Knox County Health Department.

“All of our air quality measurements in Knox County are meeting the federal standards,” said Lynne A. Liddington, director of Knox County Air Quality Management.

That wasn’t always the case for Knox, Anderson, Blount, Loudon and Roane counties. Those counties along with Hamilton, which includes Chattanooga metro, have been the only Tennessee counties designated by the EPA as “nonattainment” for failing to meet the National Ambient Air Quality Standard (NAAQS) for limiting PM2.5 as required under the Clean Air Act.

With the improvements, TDEC is in the process of seeking to get the “nonattainment” rating lifted.

It’s all about particle matter 2.5 (PM2.5). These are tiny particles 2.5 micrometers in diameter, a fraction of the diameter of a human hair. According to the EPA’s AirNow.gov website: “Fine particles are produced from all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning and some industrial processes.”

The recent Sevier County forest fires, for example, created a big bump in PM2.5, which was greatly responsible for sending hundreds of East Tennesseans to hospitals and doctor’s offices with respiratory problems. The extent of that bump is still being analyzed by TDEC and Knox Air Quality. Particles as small as 2.5 micrometers are a significant problem because they can easily get into lungs. They are even smaller than PM10, the category in which pollen, dust and mold fall.

The fine particles can cause: “irritation of the eyes, nose and throat; coughing, chest tightness and shortness of breath; reduced lung function; irregular heartbeat; asthma attacks; heart attacks; and premature death in people with heart or lung diseases,” the EPA states on AirNow.gov. “They are the main cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas.

In short PM2.5 is a nasty little bugger. It is composed of nitrates, sulfates, ammonia and organic carbon. If you live around Knoxville, you were breathing too much of it for some time. A chart on the EPA website shows those five counties being rated as nonattainment at least as far back as 2009.

For a while, they weren’t even close. Particle Matter 2.5 is measured in several ways including in micro-grams per cubic meter of air, called ug/m3. The EPA has been tightening its maximum allowable limit for ug/m3 from 15.0 in 1997 to 12.0 in 2006. Knox County was testing the air at three sites for 19982000: Francis Road, Vermont Avenue and Mildred Drive. Back then those three sites had ug/mc3 numbers of 19, 21.2 and 17.7, respectively. Test results are analyzed for three-year cycles.

“Industry and transportation were the leading causes of air pollution in this area,” Liddington said.

The fact that Knoxville is at the intersections of Interstates 40 and 75 made it a particular breeding ground for vehicle exhaust, but there likely was an even bigger contributor.

“Historically, TVA’s fossil plants (primarily Bull Run and Kingston) were substantial contributors to PM2.5 nonattainment in the area,” said TDEC spokeswoman Kim Schofinski in emailed responses to News Sentinel questions.

When a county is designated nonattainment, it is required to show progress toward meeting the guidelines within a three year period.

The good news is that the five-county area has improved its air quality greatly, so much so that the TDEC is in the process of asking the EPA to lift the nonattainment designation.

Tests for 2013-15 include an additional site on Stewart Street. They show Francis Road at 9.2, Stewart Street 9.9, Vermont Avenue 9.9 and Mildred Drive 9.1.

A public hearing was held at the TDEC Environmental Field Office in Knoxville on Nov. 28 before the Tennessee Air Pollution Control Board as part of the process to get the area redesignated. The board later approved TDEC’s request to the EPA to get the area redesignated, and TDEC submitted that request to EPA on Dec. 20. In the wide world of government acronyms, this comes in the form of a State Implementation Plan (SIP) revision. “The Clean Air Act (CAA) requires EPA to determine if the SIP revision meets CAA completeness criteria with 60 days of receipt,” Schofinski said. “The maximum time it could take is 20months (to gain re-designation) from when TDEC submits the SIP revision to the EPA for approval and official re-designation from nonattainment to attainment.

“The Knoxville area is currently measuring air quality concentrations that are attaining all the particulate matter standards, including the newly established 2012 PM2.5 standards,” said Enesta Jones, EPA spokeswoman. “Previously, the Knoxville area was designated as being out of compliance (nonattainment) for the 1997 and 2006 PM 2.5 standards; however, recently, the area has measured air quality meeting both these standards.”

How did improvements happen?

The five-county area took a big leap forward in improving air quality when TVA installed two scrubbers at its Kingston Fossil Plant in June 2010. When the plant was made operational in 1955, it was the largest coal burning power plant in the world, according to the TVA.com website. “Until TVA installed the scrubbers, the Kingston TVA fossil fuel plant was a contributor” to causing the PM2.5 problems, Liddington said.

According to information on the TVA site, “a scrubber removes sulfur dioxide emissions by routing flue gases produced from burning coal through a limestone and water mixture.” “SO2 (sulfur dioxide emission) reacts with other air pollutants to form sulfate particles, which are constituents of fine particulate matter (PM2.5),” the EPA states on its website. “Between 2000-2015, Bull Run and Kingston have each reduced SO2emissions by about 98 percent,” Schofinski said. “Several other facilities have recently converted from coal to natural gas, including the University of Tennessee Steam Plant and Tate & Lyle.”

In addition vehicle PM2.5 production has been shrinking.

“Federal vehicle standards have significantly reduced the N0x and SO2 emissions from motor vehicles, which has led to overall reductions in motor vehicle emissions in the area,” Schofinski said. “Our projected on-road mobile source inventory anticipates further reduction in motor vehicle emissions as older vehicles are gradually replaced with newer, lower emitting cars and trucks.”

A change some Tennessee counties, including Knox, made several years ago in how they measure PM2.5 likely also contributed to helping make the case for redesignation.

“Both TDEC and the Knoxville local program are using the Intermountain Laboratory (IML) for PM2.5 filter weighing,” Schofinski said. “The reason the state switched to IMP was because the state Health Department’s lab was unable to properly maintain the proper conditions necessary for weighing PM2.5 filters.”

Amber Talgo of Knox County Air Management said the EPA’s issues with the state lab, used by Knox and other counties, continued even into 2013.

“It wasn’t until 20132015 data was complete and certified by EPA that Knox County was able to be (in a position) to be designated attainment,” she said.

Talgo said, although the testing was judged accurate, the EPA’s concerns were that weather conditions such as humidity were not being taken into account. Even those tests that the EPA would not approve showed the area was not passing the air quality guidelines. So, while Knox County is now acknowledged by all involved to be meeting those guidelines, Knox and the other four counties will have to wait on their redesignation until the EPA hands down its ruling.

Out of the woods?

Meeting attainment is an ongoing process and, while agreeing that the Knox area is doing so now, the EPA warns that it’s no time to rest on its laurels.

“The state is developing plans to show how the Knoxville area will continue to achieve compliance with the standards for at least the next 10years,” Jones said. And, while the EPA might be satisfied, the American Lung Association still had issues with Knoxville’s air as late as April when it gave Knox County an “F” for air quality.

In a News Sentinel story at the time, Liddington said the association’s grade is partially based on the number of days it “alerts” residents to air that’s potentially harmful to breathe with its Air Quality Index. East Tennessee is likely to not do well in that category for the remainder of last year because of the historically bad wildfire season during a handful of days the Air Quality Index shot into the “Red Alert” area. Liddington said the air alerts are merely predictions that “error on the side of caution” and aren’t an accurate measure of air quality.

Source: Knoxville News Sentinel, by Steve Ahillen

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