Is Ozone safe when breathed in?

Inhaling ozone can cause respiratory irritation, including coughing, shortness of breath, wheezing, sore throat, chest pain, and inflammation and damage to airways.

Why here

Ozone is a powerful oxidant that directly reacts with and damages the cells lining the airways and lung tissue when inhaled.

What would have to be true

Even relatively low levels of ozone can cause health effects. The U.S. EPA's National Ambient Air Quality Standards (NAAQS) for ozone are 0.070 parts per million (ppm) averaged over eight hours. The Occupational Safety and Health Administration (OSHA) permissible exposure limit for workers is 0.1 ppm as an 8-hour time-weighted average. The National Institute for Occupational Safety and Health (NIOSH) recommends an upper limit of 0.10 ppm, not to be exceeded at any time. The Food and Drug Administration (FDA) requires ozone output of indoor medical devices to be no more than 0.05 ppm.

Ozone inhalation can aggravate existing lung diseases such as asthma, emphysema, and chronic bronchitis, and increase the frequency of asthma attacks.

Why here

Ozone inflames and damages airways, making them more susceptible to irritation and exacerbating pre-existing respiratory conditions.

What would have to be true

Effects can be more serious in people with lung diseases, even at levels found in many cities during summer months.

Ozone can reduce lung function, and repeated short-term ozone exposure may lead to permanent lung damage and reduced lung function, particularly in children.

Why here

Ozone damages the cells lining the air spaces in the lung, leading to inflammation and potential scarring over time.

What would have to be true

Long-term ozone exposure is associated with increased respiratory illnesses. Children are at greatest risk because their lungs are still developing and they are more likely to be active outdoors when ozone levels are high.

Long-term ozone exposure is associated with increased respiratory illnesses, metabolic disorders, nervous system issues, reproductive issues (including reduced male and female fertility and poor birth outcomes), and increased respiratory and cardiovascular-related mortality.

Why here

As a powerful oxidant, ozone can cause systemic effects beyond direct lung damage with prolonged inhalation exposure.

What would have to be true

Long periods of breathing ozone, defined as longer than eight hours, including days, months, or years. A 10 ppb (0.01 ppm) rise in ozone levels has been associated with a 4% increase in respiratory mortality.

Ozone is a lung and respiratory irritant that can cause coughing, chest tightness, shortness of breath, throat irritation, and can worsen chronic respiratory diseases like asthma, potentially leading to permanent lung damage with elevated exposure.

Why here

Ozone generators are designed to intentionally release ozone into indoor spaces, and other air cleaning devices can produce it as an unintended byproduct, leading to direct inhalation by occupants.

What would have to be true

Exposure to ozone in indoor air, even at relatively low concentrations (e.g., above 0.05 parts per million (ppm), which is the FDA limit for medical devices and CARB's emission limit for air cleaners), can cause respiratory irritation and damage. The WHO's peak season 8-hour mean guideline for ambient ozone is 60 µg/m³ (approximately 0.03 ppm).

Ozone reacts with other common indoor chemicals, such as those from fragrances or cleaning products, to create additional toxic pollutants, including formaldehyde and ultrafine particles, which can also be irritating and corrosive.

Why here

When ozone is introduced into indoor air, it chemically reacts with volatile organic compounds (VOCs) and other substances commonly found in homes, forming secondary pollutants that are harmful when inhaled.

What would have to be true

This reaction occurs when ozone is present in indoor air, even at concentrations below those considered effective for air purification, as ozone reacts with common indoor chemicals.