Photo via National Environmental Satellite, Data, and Information Service

Over the past few weeks, there has been a light haze in the air from the Canadian fires and at times, the haze has become very dense. The wind has been carrying the smoke down into the United States and decreasing air quality across our state of Illinois. As shown in the animation below on June 8th, 2023 from the National Environmental Satellite, Data, and Information Service, the smoke was stuck between the low-pressure system over the state of Maine and the high pressure system over the central U.S. According to NOAA meteorologist, Brian Jackson, the smoke was caught in a stationary front over Minnesota to North Carolina. This weather pattern explains the travel sequence of smoke through the Midwest and warranted an air quality alert by the Illinois Environmental Protection Agency in Springfield, Illinois. This alert is important for human health, but how is the poor air quality affecting plant health?

Photosynthesis comes up as a large concern when looking out across crop fields in the Midwest in correlation to the smoke. In 2021, there was also a similar concern for crops when there were wildfires in California. University of Minnesota Extension published an article about this topic in 2021 and addressed some of these concerns.

Wildfire smoke creates a haze in the air but diffuses the radiation from the sun in a form that is more usable for plants. Essentially the sunlight is absorbed better when the sunlight is spread out across the atmosphere rather than the light directly hitting the leaves. As far as photosynthesis goes, it has the potential to increase during these hazy times.

The real concern with wildfire smoke comes when other pollutants are introduced like ozone and aerosols. These air pollutants enter plants through their stomata, which is how CO2 is taken up to produce O2, and that is when the poor air quality can contribute to photosynthesis interference. Closer to where the fires are actively occurring, ash settling on the leaves can also become a physical barrier to light infiltration to the plant. Depending on how long the smoke lingers in the air, the plants should not become stressed and show damage. The plants can become stressed when there is prolonged poor air quality and other pollutants contributing to decreased photosynthesis.

We have collected several other recent University articles for you to learn more about wildfire smoke effect on crop growth:


Wildfire smoke and potential impacts to crops – Cool Bean

How could the haze of wildfires affect crop growth? | Agronomic Crops Network (

Purdue Crop Chat Episode 52, Northeast Indiana Crop Update & the Smoky Air from Canada – Hoosier Ag Today

Wildfire smoke impacts on crop production | Integrated Crop Management (

Smoke From Canadian Wildfires Blankets U.S. | NESDIS (

Managing wildfire smoke: impacts to crops and workers (

How Does Wildfire Smoke Impact Corn Growth? 

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About the Author: Shelby Stoner

Shelby Stoner is the 2023 Agronomy Team Intern for the Illinois Soybean Association. Originally from Congerville, IL, she just graduated from Illinois State University in May 2023 with a degree in Agronomy Management. She will be continuing her education at Illinois State in the fall pursuing her master's degree in agronomy.

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