Chapter 6 - Biophysicochemical transformations of ENMs in air

Abstract

Engineered nanomaterials (ENMs) are widely applied to meet the continuing market demand in a wide array of fields. The physicochemical properties of anthropogenic and natural nanomaterials might vary from those corresponding bulk materials in numerous ways, such as aspect ratio, reactivity, chemical composition, and toxicity. More importantly, such ENMs can undergo potential biophysicochemical transformations in the air, including physical, chemical, and biological reactions with atmospheric components such as humidity, vapors, gases, colloids, light, etc. Hence, the development of ENMs can bring significant unexplored risk factors for humans and the environment, which require substantial attention. Plants represent the major interface between the ecological system and environment, and they provide a large surface area for ENMs exposure through aboveground biomass such as leaf, and may serve as a potential pathway for ENMs transport and a route for bioaccumulation into the food chain. Therefore, it is important to understand the interactions between ENMs and plants. In this chapter, the potential transformations of ENMs in the air are discussed. Subsequently, the interactions of airborne ENMs with plant surface, including the uptake pathway, translocation pathway, and biotransformation of ENMs in plants, are explained. Finally, the negative and positive impacts of airborne ENMs on the plants are discussed.