Wildfires have torn across the western United States over the last decade. Displacing thousands of people, destroying homes and businesses, and taking lives, wildfires have become a common extreme weather event. While wildfires themselves present a dangerous public health hazard, the lingering effects of atmospheric pollution are also linked to increases in urban ozone concentrations. Ozone is a harmful air pollutant made up of three oxygen atoms and is linked to respiratory illness. Typically seen as a “good” environmental actor, ozone is the chemical compound that makes up the protective ozone layer, shielding the Earth from harmful ultraviolet radiation. However, ground-level ozone, or ozone forming below the stratosphere, acts as an air pollutant and the main ingredient in urban smog.

Wildfire smoke is known to contribute to increased ozone levels in urban areas, but the exact chemistry was never well understood. A new study has determined that the complex chemical cocktail of wildfire smoke mixed with nitrous oxide can result in harmful levels of ozone. Nitrous oxide, a common transportation byproduct, is often found in urban regions due to the high prevalence of traffic congestion. A joint project between the National Aeronautic and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) partnered with the Fire Influence on Regional to Global Environments and Air Quality flight campaign to create a flying laboratory. The research team collected air samples from this flying laboratory during times of wildfire to analyze the chemical components of the smoke plume. Using this data, lead researcher Dr. Xu and his team created an equation to calculate ozone production based on wildfire emissions.

As wildfire smoke drifts over cityscapes, the urban sources of nitrous oxide mix with the smoke to generate high volumes of dangerous ozone. Mixing could increase ozone concentrations by as much as 3 parts per billion (ppb), a figure well below the U.S. Environmental Protection Agency’s (EPA) health advisory of 70 ppb, but the increase may still result in increased respiratory distress, especially for those with pre-existing respiratory conditions. Climate change will only increase the frequency of wildfire events, leading to an increase in urban air pollution impacts. This poses a challenge for environmental regulatory agencies as wildfire smoke may undermine attempts to regulate ozone pollution.

Lu Xu is a research scientist in the tropospheric chemistry division of the National Oceanic and Atmospheric Administration. He holds a PhD in Chemical Engineering from the Georgia Institute of Technology and a Bachelors of Engineering in Chemical Engineering from Zhejiang University

Managing Correspondent: Samantha Tracy
Press Article: “Wildfire smoke may ramp up toxic ozone production in cities
Journal Article: “Ozone chemistry in western U.S. wildfire plumes
Photo Credit: Pixabay

10 thoughts on “A Deadly Mix: Wildfires and Urban Air Pollution Create Toxic Ozone

  1. The interaction between nitrous oxide (N2O) and smoke from wildfires leading to elevated levels of ozone is an interesting and concerning topic. While I don’t have access to the specific study you mentioned since my training data only goes up until September 2021, I can provide you with some general information about the relationship between nitrous oxide, wildfires, and ozone.

    1. Nitrous Oxide (N2O): Nitrous oxide is a greenhouse gas primarily produced by agricultural and industrial activities, as well as the combustion of fossil fuels. It is commonly associated with transportation emissions in urban areas due to traffic congestion and combustion processes in vehicles.

    2. Wildfires and Smoke: Wildfires release significant amounts of smoke, which consists of a complex mixture of particles, gases, and volatile organic compounds (VOCs). These VOCs include nitrogen-containing compounds, such as nitrogen oxides (NOx), which can react with other pollutants in the atmosphere.

    3. Nitrous Oxide and Smoke Interaction: When smoke from wildfires containing nitrogen-containing compounds, such as NOx, interacts with nitrous oxide in the atmosphere, a series of complex chemical reactions can occur. These reactions may lead to the formation of nitrogen dioxide (NO2) and other nitrogen-based compounds.

    4. Ozone Formation: Nitrogen dioxide (NO2) is a precursor to the formation of ozone (O3) in the lower atmosphere. In the presence of sunlight and other atmospheric conditions, NO2 can undergo reactions that produce ozone. High levels of ozone near the surface can have detrimental effects on human health and the environment.

    It’s important to note that the specific details and findings of the study you mentioned would provide more accurate and detailed insights into the exact mechanisms and impacts of the interaction between nitrous oxide and wildfire smoke on ozone levels. Additionally, the influence of other factors such as meteorological conditions, regional air quality, and the scale and intensity of wildfires can also play a significant role in the overall impact on ozone levels.

    If you have access to the study, I would recommend reading it for a more comprehensive understanding of the research findings and their implications.

  2. While the link between wildfire smoke and increased ozone levels has been recognized, the exact chemical processes involved were not well understood until a recent study. The joint effort between NASA and NOAA, in collaboration with the Fire Influence on Regional to Global Environments and Air Quality flight campaign, aimed to shed light on this issue. Their research involved collecting air samples from wildfire smoke plumes using a specially equipped flying laboratory.

  3. Wildfires are a significant source of air pollution, releasing a variety of pollutants, including carbon monoxide, nitrogen oxides, and volatile organic compounds. These pollutants can react with sunlight and heat to form ozone, particularly in urban areas that already have high levels of air pollution.

  4. The research, conducted by a joint project between NASA and NOAA, used a cutting-edge flying laboratory to collect air samples during times of wildfire.

  5. Ozone levels in the atmosphere can be dangerously high when nitrous oxide and wildfire smoke combine.
    Thanks for sharing this information.

  6. The smoke from a wildfire contains particles of fine soot and chemicals such as carbon monoxide, nitrogen oxide, and hydrocarbons. Once these particles are released into the atmosphere, they combine with the oxygen present to form ozone. Ozone levels in wildfire-affected regions can rise to levels that exceed the US Environmental Protection Agency’s standards for safe air quality. The presence of this ozone can cause respiratory problems, aggravate existing respiratory conditions, and increase the risk of asthma attacks.
    In addition to the direct impacts of urban ozone pollution on human health, the presence of ozone in the atmosphere can also have indirect effects. Warmer temperatures from high ozone levels can increase evapotranspiration and decrease air quality, leading to the release of more ozone-forming pollutants into the atmosphere. This can further contribute to the formation of ozone and create a positive feedback loop, leading to even more ozone and further health risks.
    The effects of wildfire-related urban ozone pollution can be long-lasting, with the potential to cause significant harm to public health. To mitigate these risks, local and federal governments must work together to create policies and regulations that will reduce the amount of ozone-forming pollutants released into the atmosphere. This can include reducing emissions

    1. A recent study found that the complex chemical reaction between nitrous oxide and smoke from wildfires might result in dangerously high levels of ozone. Nitrous oxide, a characteristic transportation contaminant, is typically seen in metropolitan areas due to the high incidence of traffic congestion.

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