Air Pollution,  Climate Change,  Health,  Science

Ozone, Plants and Heat Waves: Team Players in Adverse Health Effects

By The Editors

Ozone, the principal component of the mixture of air pollutants known as “smog“, is produced from the action of sunlight on air contaminants from automobile exhausts and other sources.

According to the U.S. Environmental Protection Agency (EPA) “Ozone in the air we breathe can harm our health—typically on hot, sunny days when ozone can reach unhealthy levels. Even relatively low levels of ozone can cause health effects. Breathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ground level ozone also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue.”

Image Credit:
Image Credit:


Ozone Effects on the Airways.  Ozone is a powerful oxidant that can irritate the air ways causing coughing, a burning sensation, wheezing and shortness of breath and it can aggravate asthma and other lung diseases.






In the Summer, strong sunlight and hot weather result in harmful ozone concentrations in the air we breathe. Ozone can be transported long distances by wind.  For this reason, even rural areas can experience high ozone levels.  And, in some cases, ozone can occur throughout the year in some southern and mountain regions.

Plants can reduce ozone concentrations. However, in presence of heat waves, they become stressed and stop absorbing ozone and other pollutants. Results from a new study, set to quantify the impact of increased ozone levels on human life, show that this phenomenon led to about 406 premature deaths in the UK during the 2006 Summer heat wave. All estimated premature deaths were in addition to human health and mortality impacts from the heat itself.

Photo Credit: Wikimedia Commons
Photo Credit: Wikimedia Commons

The study, entitled “Scorched Earth: How will changes in the strength of the vegetation sink to ozone deposition affect human health and ecosystems?” was published a few days ago (July 18) in the scientific journal Atmospheric Chemistry and Physics.  

Dr. Lisa Emberson, lead author of the study, explains that “Vegetation can absorb as much as 20 per cent of the global atmospheric ozone production, so the potential impact on air quality is substantial. During heat waves – when the ground is especially dry – plants become stressed and shut their stomata (small pores on their leaves) to conserve water. This natural protective mechanism makes them more resilient to extreme heat and high ozone levels, but it also stops them from absorbing ozone and other pollutants.”

The extent of the problem depends on how dry the soil is, since it is the combination of heat and drought that stresses plants the most.

Dr. Emberson says the study highlights the importance of understanding the frequency with which such heat waves and droughts will occur in the future as well as how ozone uptake by vegetation is affected by droughts, extreme heat, and interaction with other pollutants.


  • Kalpesh Patidar

    Since the ozone can be absorbed through the stomata of the plants. It would be a good idea to find plants that are known to keep their stomata open the most in the environment one lives in, and keeping these plants around the house and near outside openings should ideally help reduce somewhat exposure at least within the household. This would be great because most people spend a great amount of time being home. With knowledge like this, the cities should devote into multiple parks that can provide housing for a grand multitude of plants to help reduce this pollution till a better solution can be found. Also with the use of genetic recombination, one can create a plant for optimal ozone intake. These plants could can better help the ozone issue if used widely.

  • sabzter

    The ozone, which is a highly active form of oxygen, has a reputation for creating atmospheric problems to humans, animals and plants. While NASA’s Earth Observatory suggests that the ozone reduces the human immune system’s ability to fight bacterial infections in the respiratory system (Allen, 2002). They also state that it decreases plant immunity as well. High ozone concentrations not only plant affect growth, but also affects soil fertility. Plants in low ozone concentrations metabolize carbon dioxide allowing microbes in the soil make use of the carbon to enrich the soil. While heat plays a major role in the stress response of plants, exposure to high ozone concentrations lead to the metabolizing of less carbon dioxide, giving soil microbes less carbon grow and thrive (Allen, 2002). This reduces soil fertility, thus suppresses nitrogen fixation and leaves malnourished soil for plants to live and survive on.

    Reference: Allen, Jeannie. “The Ozone We Breathe.” 19 Apr 2002. Web. 15 Sep 2013.

  • jgunn5

    Breathing unhealthy levels of ozone can make people sick. I personally deal with health effects of the ozone. Due to those effects, when I was younger I was prone to getting colds easier than most. I would have a sore throat with a horrible dry cough, and I had breathing problems. Over the years from being exposed to high ozone levels my asthma has worsened and some of my lung tissue has been scarred, luckily for me not much of my lungs has been damaged, so I only face wheezing and soreness problems.

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