2. Environmental Safety Assessment—

2. Environmental Safety Assessment—Finding the Contributing Factors to Environmental ToxicityThe famous statement of “There is plenty of room at the bottom” by Richard Feynman back in 1959 painted a bright future for nanotechnology.[6] Feynman’s vision of manipulating individual atoms and building novel materials from the bottom up has since inspired generations of materials scientists and led to the creation of sophisticated nanochemistry and libraries of nanomaterials with ever-changing compositions, structures, and architectures. On top of the periodic table of elements that can be used as building blocks for nanomaterials, other nano￾specific physicochemical characteristics, such as size, shape, surface functionalization/defect, and nanoparticle aggregation/agglomeration state, have created additional layers of sophisti￾cation to nanomaterials. As depicted in Figure 1, nanomaterials