Ozone levels here, or what most refer to as smog, are often twice the federal health standard. In 1995, the standard was exceeded on 98 days at one or more Basin locations, most frequently in the east San Gabriel Valley. The answer depends on the situation. How long a person is exposed to pollution, the type and concentration, the place, time and day, temperature, weather and more.
Lungs are ozone's primary target.
Studies on animals show that ozone damages cells in the lung's airways, causing inflammation and swelling. It also reduces the respiratory system's ability to fight infection and remove foreign particles. Ozone may pose a particular health threat to those who already suffer from respiratory problems such as asthma, emphysema and chronic bronchitis. Ozone may also pose a health threat to the young, elderly and cardiovascular patients. Ozone affects healthy people as well.