ABSTRACT
This chapter details damage at several levels. Damage can occur at the system level, but many of the effects are initiated at the molecular scale. An environmental pollutant at a sufficiently high concentration can critically influence the physiological processes of a living organism. In order for a pollutant to exert its toxicity on an organism, it must first enter the host and reach its target site. An atmospheric pollutant-induced plant injury may follow a pathway that includes exposure, uptake, transport, storage, metabolism, and excretion. Stomatal resistance is vitally important in affecting pollutant uptake. The resistance is determined by stomatal size, number, anatomical characteristics, and the size of the stomatal aperture. The epidermis is the first target of atmospheric pollution as the pollutant first passes through the stomata of the epidermal tissue. Exposure to a pollutant by a host organism constitutes the initial stage in the manifestation of toxicity.
