Oxidative Stress, the Paradigm of Ozone Toxicity in Plants and Animals.

Tropospheric ozone represents a relevant atmospheric pollutant, because of its strong oxidizing potential. The risk for animal (human) and plant health, at molecular and cellular level, arises from the oxidative damage to lipids, proteins and nucleic acids, depending on the dose. Therefore, ozone concentration and exposure time determine the chronic or acute toxicity and, consequently, the severity of injury at biochemical and physiological level. In living organisms, reactive oxygen species (ROS), directly or indirectly derived from ozone exposure, are scavenged by enzymatic and non-enzymatic antioxidant defensive mechanisms, overall deputed to preserve cell structures and biomacromolecules from the oxidative damage. These defences are essentially those also involved in detoxifying the ROS inevitably produced by the metabolism of organisms living in oxygenic atmosphere.