  This review is written with the goal of informing public health concerns
related to nanoscience, while raising awareness of nanomaterials toxicity among
scientists and manufacturers handling them. We show that humans have always
been exposed to nanoparticles and dust from natural sources and human
activities, the recent development of industry and combustion-based engine
transportation profoundly increasing anthropogenic nanoparticulate pollution.
The key to understanding the toxicity of nanoparticles is that their minute
size, smaller than cells and cellular organelles, allows them to penetrate
these basic biological structures, disrupting their normal function. Among
diseases associated with nanoparticles are asthma, bronchitis, lung cancer,
neurodegenerative diseases (such as Parkinson`s and Alzheimer`s diseases),
Crohn`s disease, colon cancer. Nanoparticles that enter the circulatory system
are related to occurrence of arteriosclerosis, and blood clots, arrhythmia,
heart diseases, and ultimately cardiac death. We show that possible adverse
effects of nanoparticles on human health depend on individual factors such as
genetics and existing disease, as well as exposure, and nanoparticle chemistry,
size, shape, and agglomeration state. The faster we will understand their
causes and mechanisms, the more likely we are to find cures for diseases
associated with nanoparticle exposure. We foresee a future with
better-informed, and hopefully more cautious manipulation of engineered
nanomaterials, as well as the development of laws and policies for safely
managing all aspects of nanomaterial manufacturing, industrial and commercial
use, and recycling.
