Inhaling ground-level ozone can result in health effects that are observed in broad segments of the population, including respiratory symptoms, reduced lung function, and airway inflammation

Respiratory symptoms can include coughing; throat irritation; pain, burning, or discomfort in the chest when taking a deep breath; chest tightness, wheezing, or

How are people exposed to ozone?

  • Ozone exposure occurs when people inhale ambient air containing ozone
  • The rate of exposure for a given individual is related to the concentration of ozone in the surrounding air and the amount of air the individual is breathing per minute
  • Ozone concentrations are higher outdoors than indoors
  • Increased physical activity increases a person’s rate of ozone exposure

How does ozone react in the respiratory tract?

  • Ozone reacts with chemical constituents of airway lining fluid throughout the respiratory tract, producing very reactive chemical intermediates

What are ozone’s acute effects?

  • Ozone or its reactive products stimulate airway neural receptors, resulting in respiratory symptoms and decreases in lung function

What effects does ozone have at the cellular level?

  • Ozone or its products damage airway epithelial cells which results in inflammation, an increase in nonspecific airway reactivity, and an increase in epithelial permeability
  • Over a period of days to a week, inflammation subsides and cell damage is repaired

What are the other potential effects of short-term ozone exposure?

  • High daily ambient ozone concentrations are associated with increased school absence, increased hospital admissions for respiratory disease, and possibly increased mortality

Hoes does response vary among individuals?

  • A wide range of responsiveness to ozone exists among otherwise healthy people
  • With regard to lung function, young adults (teens to thirties) are more responsive than older adults (fifties to eighties)

At what exposure levels are effects observed?

  • People of average sensitivity experience responses at levels as low as 0.08 ppm during extended exposures
  • Asthma attacks seem to increase when 8-hour average concentrations rise above 0.06 to 0.08 ppm

What are the effects of recurrent or long-term exposure to ozone?

  • Airway injury continues to occur with ongoing, recurrent exposure
  • Some evidence suggests that long-term exposure may be related to the induction of new cases of asthma and that recurrent exposure of young children may result in abnormal development of their respiratory systems

 U.S. EPA Website