Health effects of ozone on respiratory diseases.

Ozone is known to cause bronchial inflammation and airway hyper-responsiveness via oxidative injury and inflammation. While other ambient air pollutants such as particulate matter (PM) and NO2 showed decreasing trends of mean annual concentrations, ozone concentration did not decline recently in most countries worldwide. Short-term exposure to high concentration of ozone has been associated with increased mortality and cardiovascular and respiratory morbidity in many regions of the world. However, long-term effects of ozone were less investigated than short-term exposure due to the difficulty of modeling for ozone exposure and linking between individual exposure and health outcome data. Recently developed modeling of ozone exposure enabled investigation of long-term ozone effects on health outcomes. Recent findings suggested that long-term exposure to ozone is associated with an increased risk of cardiovascular and respiratory mortality. Longitudinal studies using large cohorts also revealed that long-term exposure to ozone was associated with a greater decline in lung function and progression of emphysema. Keeping standards for ozone as well as PM is needed to protect respiratory health of the general population and subjects with chronic respiratory diseases.