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SLU researchers build displays to show how ozone affects plants

There's good ozone and there's bad ozone. The good kind sits up high up in the stratosphere, protecting us from the sun's ultraviolet rays. The bad kind is formed by burning fossil fuels and is found in the smog in Los Angeles and China. 

Bad ozone can cause health problems for children, for the elderly and people with lung diseases like asthma. It can also harm other living things, like plants. But like other greenhouse gases, it is invisible. So it's hard for scientists to show people the effects of bad ozone, which contributes to climate change, said Jack Fishman, professor of earth and atmospheric sciences at Saint Louis University. 

To get the message across, in recent years, Fishman and other researchers at SLU set up special gardens funded by NASA to demonstrate how ozone levels affect living organisms. Their work is expanding now that they've received a $91,000 grant from the Environmental Protection Agency to exhibit such plants year-round in "ozone chambers."

"Unless it's in really, really high concentrations, you don't see anything," Fishman said. "Even if you see it, you don't know what kind of damage it's doing."

The researchers' gardens contain plants such as the common milkweed and snap beans that are sensitive to ozone. Beyond levels at 40 parts per billion, the plants will show signs of ozone damage mainly through browning in the leaves. An average summer day in St. Louis can yield ozone levels up to 55 parts per billion.

"Instead of showing people pictures, you show them actual, real-time impacts of something that's happening to our planet," said Fishman, who before coming to St. Louis studied air quality at NASA for 30 years. 

Credit Provided by Saint Louis University
Where the ozone gardens are located

Through NASA's satellite technology, he saw the effects that ozone was having on agriculture. For example, the data showed that elevated ozone levels caused a drop in soybean crop yields by approximately 10 percent. 

Since 2012, SLU scientists have set up five gardens, which include its first one at the Saint Louis Science Center. With the EPA grant, the project has expanded to display ozone-sensitive plants year-round, since the gardens can only be seen in warmer seasons. But until now, the gardens could only display the plants in warmer seasons. The new EPA grant has paid for "ozone chambers," including one at the Missouri Botanical Garden. 

The EPA's grant will support the program through 2017. 

Eli is the science and environment reporter at St. Louis Public Radio.