Shelby Co. Health Department issues first-ever “Code Purple” air quality alert


Memphis metro residents got an air quality wake-up call that seemed to come out of nowhere today.  A Code Orange Air Quality Alert that has become the norm under hot and stagnant air conditions was raised to Code Red about 4:30pm as ozone levels climbed, then raised again to uncharted territory – a Code Purple alert – two hours later.

Though the unprecedented Code Purple only lasted for about 90 minutes until the sun set, it still seemed to catch many metro residents by surprise.  The overwhelming comment on MWN’s Facebook post relaying the information was “wow!”

EPA color-coded air quality forecasts and their health concern level

Shelby County Health Department air pollution meteorologist Mike Goldstein indicated that this was the first ever Code Purple issued for the metro, which includes Shelby County, as well as Crittenden County in east AR and DeSoto County in northwest MS. “Our numbers are …as high as I’ve seen in many years,” Goldstein said.

A Code Purple, which is the second highest of the color-coded air pollution levels, means that the general population, not just those who are in the “sensitive groups” category, could be affected. Ground-level ozone is different from upper-level ozone that people generally think of when referencing a hole in the ozone layer. Low-level ozone is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources react chemically in the presence of sunlight. Ozone at ground level is a harmful air pollutant.  At Code Purple levels, ozone can cause serious and lasting damage to the lungs.

Diagram courtesy

As long as hot high pressure remains over the Mid-South, MWN expects at least Code Orange alerts to be issued daily.  If the right conditions come together, we could see more Code Red days, though hopefully not Code Purple.  You can keep up with the current and forecast air quality levels, as well as tips to help reduce air pollution on the MWN Air Quality page or at

For weather information for Memphis and the Mid-South, where and when you need it, visit on the web, on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

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