Ozone or “O3” is a colorless gas composed of three atoms of oxygen (O3). There are two types of ozone, both “good” ozone and “bad” ozone.
What is “Good” Versus “Bad” Ozone?
Ozone is either considered “good” or “bad”, depending on where it occurs. “Good” ozone is also known as stratospheric and “bad” ozone is more commonly known as ground-level.
Stratospheric Ozone
The “good” ozone, otherwise known as stratospheric, occurs naturally in the upper atmosphere. This ozone forms a protective layer that shields us from the sun’s harmful ultraviolet (UV) rays. The sun’s UV rays can cause UV radiation. Potential health effects of UV radiation include skin cancer, skin damage such as premature aging, cataracts and other eye damage, and immune suppression.
Ground-level Ozone
The “bad” ozone or ground-level ozone is sourced from human activity. This harmful air pollutant affects people, the environment and is the main ingredient in “smog”.
How is Ground-level Ozone Formed?
Ground-level ozone is created by chemical reactions of pollutants in the presence of the sun. The pollutants involved in these chemical reactions include oxides of nitrogen (NOx) and volatile organic compounds (VOCs). The sources of these pollutants can be emitted by cars, power plants, industrial boilers, refineries, chemical plants, and so on.
The Environmental Protection Agency (EPA), breaks this down into the following imagery:
Who is at Most Risk from Ground-level Ozone?
While everyone is exposed to ozone at some level, several groups of people are more sensitive. If you or someone you know is at risk, consult your physician to learn more about precautions to reduce or prevent exposure to ozone.
- People with existing lung diseases can be particularly sensitive to ozone due to it being in the air we breathe. The effects of ozone on lung diseases may include increased medication use, doctor and emergency room visits, and hospital admissions. These lung diseases may include asthma and chronic obstructive pulmonary disease or “COPD”, which includes chronic bronchitis and emphysema.
- Children, including teenagers, have lungs that are still developing and are more likely to have asthma. In addition to these sensitivities, they are generally outdoors more often. Outdoors, especially during warmer weather, have higher levels of ozone.
- Older adults are more likely to have pre-existing lung disease and are therefore more sensitive to ozone.
- Active people outdoors, of all ages, are more sensitive to ozone. As mentioned previously, the outdoor air contains higher levels of ozone. Those who participate in physical activity tend to breathe faster and deeper, drawing more ozone into the body. These people include both those who exercise outdoors or do physical work outdoors.
- People with reduced intake of certain nutrients are also more susceptible to ozone. Those with a reduction or deficit of vitamins C and E are at a greater risk from ozone exposure.
- Some healthy people may be more sensitive to ozone even without any of the risk factors that the other sensitive groups have. This category applies to those who may experience health effects at lower ozone levels than the average person.
What are the Health Effects of Ozone?
Exposure to ozone affects the lungs and respiratory system in many ways depending on your risk level and amount of exposure. See below for potential health effects of ozone.
- Irritation of the respiratory system. This irritation can cause coughing, wheezing throat soreness, airway irritation, chest tightness, or chest pain when taking a deep breath.
- Reduction of lung function can be uncomfortable, and you may notice that you are taking more rapid and shallow breaths than normal. This reduced lung function may also make it more difficult to breathe deeply and vigorously, especially while exercising.
- Aggravate asthma and other chronic lung diseases, such as emphysema and bronchitis. Those with chronic lung diseases visit doctors and emergency rooms when concentrations of ozone are high. Specifically, those with asthma need to be precautious when it comes to ozone. Ozone makes people more sensitive to allergens, which are the most common trigger for asthma attacks. The other health effects that come along with ozone such as reduced lung function and airway inflammation, affect asthmatics more severely than others. Consulting a doctor and following a plan of action is suggested for those with lung diseases, especially asthma.
- Increase susceptibility of the lungs. Ozone makes the lungs more susceptible due to the damage it has on the lungs and their defenses.
- Inflame and damage the cells that line the lungs. After the cells in the lungs are damaged, they replace and shed the old cells. Repeated occurrences of this type of inflammation may permanently scar and reduce the function of the lungs.
- Cause permanent lung damage. Children may experience lung damage to their still-developing lungs, leading to reduced lung function into adulthood. Ozone exposure to adults may accelerate the natural decline in lung function that occurs with age.
Effects of Ozone Pollution on the Environment
The effects of ozone don’t stop at humans. Ozone affects sensitive vegetation and ecosystems. It is particularly damaging during the growing season.
Ozone’s Effect on the Ecosystem
Negative impacts of ozone onto the ecosystem include:
- Changes to water and nutrient cycles
- Changes to habitat quality
- Changes to the specific assortment of plants present in a forest
- Loss of species diversity; this means less variety of plants, animals, insects, and fish
Ozone’s Effect on Sensitive Plants
Ozone damages plants by entering leaf openings and oxidizes (burns) plant tissue during respiration. Effects include the following:
- Reduction of photosynthesis
- Slowing of the plant’s growth
- Increase sensitivities to:
- Disease
- Harm from severe weather
- Effects of other pollutants
- Damage from insects
- Reduction of crop and timber yields
- Ozone disturbs the stability of ecosystems, leading to sensitive species dying
- Some plants may show visible marks on their leaves
