Hamilton County's air quality continues to suffer as a result of climate change as hotter temperatures negatively impact ozone levels nationwide, according to a new report from the American Lung Association, but a county official is discrediting those findings, assuring residents the air quality is better than it's ever been.
The county received a "D" grade for high ozone days, which ranked it among the worst counties in Tennessee, according to the 20th annual State of the Air report, sliding from last year's "C" rating. Only Shelby County, which received an "F," ranked lower. The report used the most recent air pollution data, collected between 2015, 2016 and 2017, for counties with air quality monitors.
"We're seeing more ozone days across the country from warmer weather, which makes ozone more likely to form and harder to clean up," American Lung Association in Tennessee Healthy Air Campaign Manager Christine Hart said. "Climate change plays a big role in ozone pollution."
The Chattanooga area is disproportionately affected by temperature changes due to the area's topography, Hart said. The surrounding mountains trap pollutants into the valley, creating a bowl for smog to settle. Smog is also caused by vehicle emissions, raising concerns from the lung association about the state's attempt to end a longstanding requirement for emissions testing in the county.
The high ozone levels can shorten life, cause lung cancer and have other harmful effects, according to the report. The increased levels put anyone who spends time outdoors at risk but especially affects children and teens, anyone older than 65, people who work or exercise outside, people with existing lung diseases, and people with cardiovascular disease.
The "report adds to the evidence that a changing climate is making it harder to protect human health," according to the report. "The three years covered in this report ranked as the hottest years on record globally. High ozone days and spikes in particle pollution zoomed, putting millions more people at risk and adding challenges to the work cities are doing across the nation to clean up."
However, the findings are frustrating for county leaders and citizens who have worked for decades to clean the air, said Bob Colby, the director of the Chattanooga-Hamilton County Air Pollution Control Bureau. The American Lung Association standards are tougher than standards set by the Environmental Protection Agency and don't exclude events the EPA considers to be outside human control, such as wildfires, Colby said.
"Their formula doesn't count in the real world," he said. "The one that counts is the EPA standards, and they say we meet them all. The American Lung Association disagrees with where the levels are set. They have constantly throughout the years."
Colby added that county leaders have worked incredibly hard throughout his 30 years with the bureau to continue to meet tightening EPA standards. He is pleased by the work of local residents and officials to famously improve air quality from the worst in the country 50 years ago to among the best in 2017. He also believes the report ranks air quality too harshly.
"We're really not in love with what the American Lung Association does because many counties throughout the U.S. are meeting the health-based EPA standards but are getting bad grades in this," he said. "The air is cleaner than it has ever been. We're pretty much able to say that every year, and it's getting cleaner and cleaner and cleaner."
The report looks at two key readings: ozone, also known as smog, and particle pollution, known as soot. It found that the air quality in the Chattanooga area is still much better than it was in the mid-to-late 20th century - and is much better nationally than it was a decade ago - but has slid locally since the 2017 report found the Chattanooga area was among the best in the country in air quality, anchored by low particle pollution levels. Hamilton County received a "B" grade for particle pollution in this year's report.
For the 19th time in 20 years, Los Angeles had the worst ozone pollution in the U.S. Three Tennessee counties - Anderson, DeKalb and Wilson - received an "A" rating for ozone days. Dyer, Lawrence, Madison, Maury, Montgomery, Putnam, Shelby and Sumner counties all received "A" ratings for particle pollution levels.
The lung association's goal is for the report to educate the public about air safety and whether residents are living with unhealthy levels of smog or soot. State organizations and the lung association are ramping up educational efforts ahead of Tennessee's Air Quality Awareness Week. This year's theme is "Check the AQI and Get Outside," encouraging residents to stay informed about the air quality index.
Participating groups are working on an air quality flag program, similar to the federal fire danger signs. Air quality is classified into five color-coded categories: green, yellow, orange, red and purple. The groups are recruiting schools to fly a flag matching the color of the day's air quality.
Contact staff writer Mark Pace at mpace@timesfreepress.com or 423-757-6659. Follow him on Twitter @themarkpace and on Facebook at ChattanoogaOutdoorsTFP.