Wildfire Smoke Impacts



The Canadian Wildfires are playing havoc on humans, livestock, and agriculture. At least 3,000 Canadian wildfires have burnt over 20 million acres with over 500 wildfires still active. The fire season in Canda runs from May to October and this is the worst fire season (Level 5) since 1989. Dry weather, drought, plus poor forestry management has led to a lot of fuel for these wildfires, resulting in smoke and air pollution for the Midwest and Northeastern USA.

The hazy atmosphere is due to excess smoke and fine particulates in the atmosphere and can cause lung and breathing issues. Fine particulate matter (PM 2.5) in smoke inhaled in the lungs can lead to many health problems. Wildfire smoke symptoms include coughing, stinging eyes or eye irritation, fatigue (tiredness), headaches, rapid heartbeat, scratchy throat, short breath, runny nose, and wheezing. People with asthma and heart disease are at the most risk of having adverse reactions to the smoke and fine particulates.

Humans are not the only creatures at risk. Pets, livestock and wildlife can also suffer from smoke inhalation. Animals need to breath good clean air, just like humans so when the air is full of toxins, it impacts their health. Animals and humans under air pollution stress will experience breathing issues, have more inflammation, and have reduced immune functions. Expect slower weight gains in livestock or even a loss of weight if the impact is severe. Plants also suffer from poor air quality. Under smoky conditions, the plants may reduce their rate of photosynthesis by up to 50%. The stomata on the underside of leaves will shut down, so the plant can not take in carbon dioxide for plant growth. The hazy conditions also reduce sunlight needed to make photosynthesis work. Crops are already at least 2-3 weeks behind in their development, so continued wildfire smoke this summer may reduce and restrict plant growth, leading to possible reduced crop yields.

Corn is the most susceptible to reduced yields due to weaker stalks, stalk pathogens, and insect damage to weak plants. Corn is affected by three major factors: reduced light intensity, increased sunlight diffusion from the haze, and increased atmospheric ozone levels. Wildfire smoke has the biggest impact on reduced solar radiation. Just like too much cloud cover, less solar radiation leads to less photosynthesis, less sugars, and less proteins and enzymes produced for biological growth. Corn is a C4 plant which are affected the most with C3 plants like soybeans and wheat less affected. C4 refers to the biological process of producing four carbon sugars versus three carbon sugars in C3 plants.

Smoke can also diffuse or scatter sunlight, making it less intense. Some taller or denser plants with a higher leaf canopy may benefit from sunlight that is diffused sunlight while shorter less dense leaf canopy plants may suffer. While results can vary for different plants, overall; if the smoke gets too intense, less sunlight equals less photosynthesis.

The third factor is increased ozone production which naturally occurs in the upper atmosphere. Ozone in the upper atmosphere protects humans and plants from ultraviolet radiation. However, in the lower atmosphere it is harmful to both humans and plants because it is highly reactive. Ozone is a strong oxidant and can damage plant tissue. When high ozone levels occur, it is thought that dicot plants like soybeans may be more affected than monocot plants like corn, although both are susceptible to yield loss from ozone pollution (Heagle, 1989; McGrath et al., 2015).

Smoke and fine particulate air pollution can also impact engine performance. To burn fuel cleanly and efficiently, engines need clean oxygen, not fine particulates (soot) or smoke which has more carbon dioxide and other noxious gasses (nitrogen oxide). Smoke tends to reduce engine performance and clog up air filters on tractors, trucks, and other vehicles. Vehicles may experience some strange sounds and have reduced performance and reduced engine power. Sensors may malfunction and check engine lights problems may become more frequent. Smoke and air pollution also has an impact on solar collectors. Many farms are using solar collectors to generate electricity for livestock or farm buildings. The Canadian wildfire smoke reduced solar collection at least 20-25% in June 2023 compared to the previous year due to the increased haze.

Smoke can also impact the weather. One slightly positive factor is that smoke particulates create denser clouds and increases water droplets by a factor 5X. However, some of these water droplets may be smaller and may not come to earth. Smoke can also impact the wind direction and change weather patterns. Let’s hope for less smoke, better weather, and better growing conditions.