Ozone: What Is It?

• October 20, 2021

Ozone: What Is It?

When you hear the word “ozone”, you probably picture the ozone layer; the layer of the earth’s atmosphere that protects the planet from the harmful UV rays of the sun. While it’s true that this is a type of ozone and it’s beneficial, when ozone occurs at ground levels, the very gas that protects us can actually be extremely harmful; not only for individual health, but for the health of everything on earth – including the planet itself. Breathing in ozone gas can exacerbate respiratory issues, such as asthma and chronic obstructive pulmonary disease (COPD).

In the United States, the federal Air Quality Index measures pollutants in the air, including particulate matter and ozone. While keeping tabs on the Air Quality Index is certainly a good idea, sometimes, you can actually detect ozone yourself, due to the very distinctive scent that it produces. Understanding the basics of ozone is important so that you can protect yourself and avoid the adverse health effects that exposure to the harmful gas can pose. What is ozone? Why is it harmful? How can you detect it? How can you minimize your exposure to ozone? To find the answers to these questions and more, keep on reading.

What is ozone anyway?

In the most basic sense, ozone is a form of oxygen. According to the US Environmental Protection Agency (EPA), ozone (or “O3”), is a “highly reactive gas composed of three oxygen atoms.” The gas is both naturally and man-made. As mentioned, it occurs in the upper atmosphere of the earth’s atmosphere (the stratosphere), as well as the lower atmosphere (the troposphere). Depending on what part of the atmosphere it is located in, ozone impacts the planet in different ways; some good and some bad.

In the stratosphere, ozone forms naturally as a result of the solar ultraviolet (UV) radiation interacting with molecular oxygen (O2). The ozone layer, which sits starts at about 6 miles above the surface of the earth and expands up to 30 miles, helps to cut out the amount of UV radiation and the harmful effects that it can cause from reaching the surface of the planet.

In the troposphere, or at ground level, ozone is primarily formed as a result of reactions between photochemicals that are produced by two major classes of air pollutants: volatile organic compounds (VOCs) and nitrogen oxides (NOx). Traditionally, these reactions increase when heat and sunlight levels are high – typically during the summer season – which results in increased concentrations of ambient ozone. As per the EPA, over the span of the past decade or so, increased concentrations of ozone have also been seen during cold weather when specific conditions are present. These conditions include high levels of local emissions of VOCs and NOx, which has specifically been seen in locations where elevations are high, such as in the Western parts of the United States, when there is a layer of snow on the ground and the air temperatures are close to or below freezing. When you see hazy conditions (known colloquially as “smog”), part of that haze is comprised of ozone gas. Primarily, hazy conditions are still most common in the summer season; however, in some parts of the country –such as southern and mountainous locations – haze can occur at any time of the year.

While some stratospheric ozone moves into the troposphere, and some VOC and NOx are naturally-occurring, most of the ozone that occurs at ground level is caused by the reactions that are brought about by VOCs and NOx that are produced by man; largely as a result of pollution caused by manufacturing and power plants, for example.

Ozone in the stratosphere and troposphere: A further examination

As mentioned, in the stratosphere, ozone’s primary job is to protect the earth from harsh radiation caused by UV rays. Stratospheric ozone breaks down and is replenished naturally; however, it has been found that man-made chemicals (caused largely by industrial manufacturing and power plants) are depleting the ozone layer. These chemicals are known as “ozone-depleting substances” (ODS), and when they are released into the air, as they travel from the planet up to the stratosphere, they slowly degrade. When ODS levels are high enough, the intensity of the UV rays that the sun produces slowly break them down, and as they breakdown, radicals, such as bromine and chlorine, are released and destroy the beneficial ozone layer.

The depletion of the ozone layer allows more UV radiation to reach the surface of the planet. High UV rays can be harmful to humans, animals, and plants. In humans, prolonged exposure to high UV levels can increase the risk of skin cancer and cataracts, and it is believed that it may suppress the immune system, too.

At the closest layer of the surface of the earth, the troposphere, ozone is classified as an air pollutant, and it can be quite harmful to humans, animals, and plants The troposphere extends about 6 miles above the surface of the earth, where it runs into the stratosphere (the layer of the atmosphere that contains good ozone). Ground-level ozone is the result of chemical reactions that occur between oxides of nitrogen (NOx) and volatile organic compounds (VOCs), as previously discussed. Man-made pollutants, such as emissions from factories, power plants, and vehicles, react with sunlight, ozone occurs in the troposphere.

While making an effort to minimize the use of substances that deplete ozone and working to restore the ozone in the stratosphere is important, learning how to detect and protect yourself from the damage that tropospheric (ground-level) ozone causes is crucial.

What scent does ozone produces?

There’s no doubt that you’ve heard people say “it smells like it’s going to rain”. In fact, you have probably experienced the scent of rain coming in yourself. What you’re smelling isn’t the rain, but rather what you are smelling is ozone. Interesting fact: the word “ozone” is derived from ozein, the Greek word for “smell”, which makes total sense, given the fact that the chemical compound known as ozone produces a powerful aroma.

The scent that ozone produces is quite distinctive; in fact, you can even smell it in miniscule concentrations as low as 10 parts per billion. What does ozone smell like? Here are a few of the ways that the scent is described:

• Metallic
• Chlorine
• Burning wire
• Sweet
• Pungent
• Electrical sparks
• “Clean”

By knowing what ozone smells like, you will be able to determine if there are high concentrations of the potentially dangerous gas in the air that surrounds you, and you can take the precautions that are necessary to protect yourself.

How does ozone affect your health?

At the stratospheric level, as mentioned, ozone is essential, as it protects the planet and everything on it from harmful UV radiation. The ozone layer can be equated to the sunscreen you apply before you head out for a day in the sun; just like sunscreen protects your skin from the harmful effects of UV rays, stratospheric ozone protects the earth from the harmful effects of the sun’s UV rays.

Direct exposure to the sun’s UV rays can increase the risk of skin cancer, which is one of the reasons why you apply sunscreen before you head out for a day at the beach, by the pool, or at the park. Research has also shown that UV exposure can increase the risk of cataracts, as well as immune system suppression. It is for this reason that scientists and climate activists are concerned about the degradation of stratospheric ozone and are exploring ways to restore it to its natural state.

With that said, however, exposure to tropospheric (ground-level) ozone, which is considered to be a pollutant, can cause a wide range of several other negative health effects. These negative effects can even occur when exposed to low levels of ground-level ozone. The majority of these issues affect the respiratory system and lungs, and can include:

• Reduced functioning of the lungs
• Inflammation of the airways
• Induction of respiratory-related symptoms

According to several studies, it has been determined that short-term ozone exposure (even up to 8 hours) can result in the following symptoms:

• Coughing
• Wheezing
• Feelings of tightness in the chest
• Shortness of breath
• Irritation of the lungs and throat
• Painful breathing, especially when taking deep breaths

The majority of these adverse effects occur as a result of narrowing of the airways. The good news is that the effects of ozone exposure can be reversed; but, it is important to note that prolonged exposure to ozone may be irreversible. As such, minimizing the amount of ozone that you and your loved ones are exposed to is absolutely crucial. Long-term effects that have been linked to ozone exposure include:

• Increased risk of developing respiratory disorders, such as bronchitis, pneumonia, and asthma
• Scarring of lung tissue, which can impair lung capacity
• Weakening of the immune system’s ability to combat bacterial infections in the respiratory system

Who is at the greatest risk of ground-level ozone?

While inhaling ozone can be hazardous to everyone, there are specific groups of individuals who have a heightened risk of experiencing health issues as a result of exposure to the pollutant. The groups of people who are most at-risk include:

• Children, as their lungs aren’t fully developed and they are more likely to be highly active outdoors
• Those who suffer from asthma
• The elderly
• Those who work outdoors
• Individuals who are deficient in vitamin C and vitamin E

How can you minimize ozone exposure?

In order to avoid the risks that exposure to ozone can cause, it is important to take active steps to reduce the amount of this pollutant that you are exposed to. Some tips that you can use to minimize your risk of ozone exposure include the following:

• Check air quality levels. Checking outdoor air quality levels is highly recommended before you spend the day outside. If reports show that the ozone levels are high, you might want to change your plants and remain inside as much as possible. You should also consider closing the windows. Avoid strenuous outdoor activities, such as exercise, yard work, biking, and sports. If you’re very active when ozone levels are high, you can end up breathing in even more of the noxious gas, which can further increase your risk of experiencing adverse health effects. If possible, wait to do any activities outside until the temperatures are cooler; in the evening, for example.
• Minimize indoor ozone levels. The majority of ozone exposure occurs outside; however, up to 75 percent of a person’s exposure to ozone actually happens inside. When outdoor ozone levels are high, be sure to close the windows in your home and cut down the rate of ventilation that is coming in from the outside. Avoid using appliances that are known to generate high levels of ozone, such as welders, plasma cutters, ozone generators, and ionizing air purifiers.
• Exercise caution when using ozone generators. A lot of people use ozone generators to improve the quality of their home’s indoor air. These air purifiers claim that they can disinfect, deodorize, and remove dangerous particulate matter; however, they produce ozone, which can cause adverse health issues. In a study that was conducted by the EPA, an ozone generator was run in a controlled home at its max setting. When the researchers sampled air from the test room, the concentrations of ozone were found to be “equal to a stage one smog alert”, an alert that is issued when local air pollution control districts notify the public to avoid partaking in some kinds of outdoor activities to reduce the risk of adverse health effects. While some manufactures state that their ozone generators are approved by governing entities, the reality is that these appliances have not be approved by any federal agency.
• Reduce ozone production. In addition to being aware about your exposure to ozone on a regular basis, you should also make an effort to reduce the amount of ozone pollution you are creating. To do so, the EPA suggests the following:
  • Conserve energy use
  • Carpool, make use of public transport, bike, or walk whenever you can
  • Adhere to gas refueling instructions to ensure efficient vapor recovery, taking care not to spill gas and tightly closing gas caps
  • Keep engines of cars, motorcycles, boats, and other vehicles properly tuned-up
  • Ensure your tires are inflated properly
  • Use paints, cleaning agents, and other products that are deemed environmentally safe
  • Try to compose or mulch yard waste materials
  • Keep vehicle idling to a minimum
  • Conserve electricity consumption as much as possible
  • Run air conditioners no lower than 78 degrees
  • Avoid using gas-powered lawn equipment, or put off using these tools until evening

Ozone pollution is a serious cause for concern, as it has the potential to cause a variety of adverse health effects. In order to combat exposure to this pollutant, being aware is an absolute must, which includes being aware of how to detect when levels are high and what you can do to protect yourself. Reducing the amount of ozone you are putting into the air is also important.