New research shows that high levels of pollution negatively affect plants and insects

Did you know that air pollution and poor air quality affects not only humans but also plants life and insects? According to a study, high levels of pollution found in several major cities worldwide can negatively impact both insects and plants.

Researchers from the University of Sheffield conducted the study, and the findings were published in the journal Nature Communications.

Nitrogen dioxide’s (NO2) adverse effects on plant life

Data from the study revealed that when plants are exposed to high levels of nitrogen dioxide (NO2), such as levels recorded in major urban centers, they are “able to better defend themselves against herbivorous insects.”

Dr. Stuart Campbell from the University of Sheffield’s Department of Animal and Plant Sciences, who also led the study, said that their research showed that plants exposed to high levels of NO2 are capable of producing more defensive chemicals in their leaves. The insects feeding on these leaves grew poorly, which implies that high levels of air pollution could have “cascading negative effects on communities of herbivorous creatures.”

Dr. Campbell, who also belongs to the P3 Centre (a center of excellence for translational plant science at the University of Sheffield), explained that while NO2 is a pollutant that is linked to severe health problems in humans, the study has also confirmed that it could also have a significant impact on plants and insects.

When exposed to nitrogen oxide, humans can suffer from negative side effects such as:

  • An increased likelihood of respiratory problems.
  • It can trigger more frequent and more intense asthma attacks. Children with asthma and older people diagnosed with heart diseases are at high risk.
  • Reduced immunity to lung infections (NO2 inflames the lining of the lungs). This can result in bronchitis, colds, coughing, flu, and wheezing.

The role of insects in ecosystems

Insects are essential to the healthy functioning of ecosystems. Aside from being important factors in food production, insect pollinators, like thousands of species of bees, butterflies, flies, and moths, are also necessary for the long-term survival of shrubs, trees, and wildflowers. (Related: Environmental pollution affects the scent of flowers, explaining the decline of various plant species and insect populations.)

Herbivorous insects that feed on plants also help return plant nutrients to the soil. These insects are also consumed by other insects, mammals, reptiles, and wild birds. Additionally, insects are needed for decomposing decaying organic matter and maintaining healthy soils. Scientists cautioned that massive declines in insect numbers are alarming, especially for those who value nature and sources of food.

Dr. Campbell warned that NO2 is a major component of smog and that NO2 levels are still very high in cities. The study findings illustrate some of the hazards of pollution on the environment, and it also emphasizes the need to resolve this issue and prevent further damage.

The international research team, which includes a researcher who is currently working at the Environmental Protection Agency (EPA), also examined if insects can affect the ability of plants to absorb NO2 from the environment. The study determined that plants that had been fed on by insects absorbed much less NO2. The researchers reported that this could be due to insects possibly influencing the amount of pollution removed from the air by urban green spaces.

While urban trees can absorb gaseous pollutants such as NO2, the effects may vary depending on the species and location. This could also be influenced by the actions of herbivorous insects.

Dr. Campbell pointed out that something must be done to protect these plant-eating insects and that continued study can help determine an effective method to do so. She concluded, “Research suggests that urban vegetation plays a modest role in taking up NO2. More work is needed, because many factors may influence the effect of urban plants on air quality, including herbivory. [Plant-feeding] insects, however, face a number of different human threats, potentially including air pollution.”

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