6. Risk Assessment and Toxic Effects of Exposure to Nanoparticles Associated with Natural and Anthropogenic Sources

Humans have been exposed to airborne particles, especially to nanoscale particles, during their developing period, but this exposure has increased enormously over the last century due to anthropogenic sources. This increase is due mainly to combustion processes where these particles are released to the environment unintentionally but the rapidly growing field of nanotechnology is likely to become yet another source for such very small particles. Nanoparticles are natural products but their tremendous commercial use has encouraged the synthesis of these fine and ultrafine particles. Accelerated production of these particles may lead to increased risks to humans and the environment. Therefore, a detailed understanding of their sources, release interaction with environment and possible risk would provide a basis for safer use of engineered nanoparticles with minimal or hazardous impact on environment. Each of these particles carries different blends of chemicals and therefore poses a different health risk. Keeping all these points in mind the present work provides up to date information on sources, different types of interaction with environment and possible strategies for risk management of nanoparticles. An understanding makes a major contribution to the risk management that is needed to ensure that utilization of nanoparticles is made safely, is exploited to their full potential and disposed off safely.