How Does Ozone Contamination Affect Crops?

Ozone can be beneficial to the planet in its stratospheric form, when it provides a protective shield which filters out the most harmful rays of the sun. However, tropospheric ozone is a damaging pollutant which can contribute to climate change, exacerbate respiratory conditions in humans and animals and, according to the results of a new study, inhibit the growth of crops such as maize.

Conducted by a team of researchers from the University of Illinois Urbana-Champaign, the study concentrated on the effects of ozone pollution on maize crop yields over a period of more than 20 years. Using sophisticated air quality monitoring techniques, they found that excessive levels of ozone in the lower layers of the atmosphere were responsible for reducing the yields produced by the food staple, as well as altering the chemicals present inside the leaves of the plant.

Where does ozone come from?

Ozone has its origin in nitrous oxide (N2O), which is emitted from the tailpipes of vehicles and the smokestacks of power plants and other industrial facilities. Once present in the atmosphere, it is broken down by sunlight and reacts with other compounds in the air to form ozone, which is when it takes on unpleasant characteristics leading to damaging consequences.

For example, ozone is a contributing factor to climate change due to its ability to retain heat, thus elevating ambient temperatures around the globe. However, it can also cause serious damage to the lungs and respiratory system of the human body when inhaled. Even relatively small concentrations of the pollutant can irritate the chest and lungs, causing coughs, sore throats and shortness of breath, as well as exacerbating previously existing conditions like asthma.

Maize impacted

Additionally, it also appears that ozone can negatively affect agricultural yields. In the aforementioned study, scientists examined how three different types of maize (two inbred varieties and one hybrid strain) performed when exposed to elevated levels of ozone in their atmosphere. Surprisingly, both inbred plants were unaffected by the contamination, but the hybrid strain suffered a 25% deficit in its overall growth.

On the other hand, the hybrid cross (which is a mixture of the other two strains) was more sensitive to the pollution and produced higher levels of the chemicals α‐tocopherol and phytosterol in a bid to deal with the ozone. This not only expands our knowledge of the ozone tolerance of maize and suggests how similar plants might deal with pollution, but also asks interesting questions about the complex nature of advanced agricultural techniques, such as engineered nanotechnology and genetically modified organisms (GMOs).