The American Lung Association has released its 2018 State of the Air report, and Knoxville is earning mixed grades when it comes to the most widespread air pollutants.
According to the report, Knoxville has seen a slight increase in some air pollutant compared to the last report that was conducted in 2014. However, the metro area earned a "Pass" in all recorded metrics for pollution, meaning levels were below the weighted national average.
Knoxville roughly is in the middle of the pack in the U.S. when it pollution levels. The report found that, while air quality has drastically improved in the past two decades, unhealthy levels of ozone and particle pollution remained in Knoxville.
The ALA said these levels could put some people with health issues at risk for premature death, as well as other serious health effects such as asthma attacks and breathing issues, as well as lung cancer for long-term exposure.
“Across the nation, the report found continued improvement in air quality, but still, more than four in 10 Americans – 133.9 million – live in counties that have unhealthful levels of either ozone or particle pollution, where their health is at risk,” said Heather Wehrheim, Director of Advocacy for the ALA in Tennessee.
In the report, Knoxville experienced 3 unhealthy days of high ozone and ranked 58th in the nation, which was slightly worse than prior reports in 2014. The report also found Knoxville had more unhealthy days compared to earlier in the decade when short-term spikes in particle pollution reached unhealthy levels in 2014-2016.
The ALA said many of these spikes were directly linked to weather patterns, particularly the rash of wildfires and drought across East Tennessee in summer and fall of 2016. The report said the spikes in particle pollution are likely to increase because of climate change and high emissions from wood-burning devices.
However, overall annual particle pollution levels were lower than the last previous recorded values between 2010-2012 at about 10.4 µg/m3.
However, when looking at the long term changes in air quality, Knoxville has come a very long way -- particularly in reducing ozone pollution.
In the mid-90s and early 2000s, Knoxville averaged more than 80 days with high ozone levels each year-- attributed to coal-fired power and vehicle emissions. Knoxville now sees less than 5 days of high ozone on average, which has been the case since 2013.
The same trends in reduction of daily and annual particle pollution could be seen. Knoxville had markedly higher levels of pollution over are larger number of days in the early 2000s, which saw a large reduction in the mid-2000s and has fallen to passable levels in this latest report.
Nationally, the ALA said air quality saw continued improvement, but four in 10 Americans still live in counties that have unhealthy levels -- at least for sensitive populations -- of ozone or particle pollution.