Anthropogenic nanoparticles

Equally as speculative as our attempts to foresee possible toxicity issues is the issue of nanomaterial exposure. Exposure will be determined in large part by the chain of production, use, and disposal of nanomaterials. Although the mobility of nanoscale particles in the environment is poorly understood, speculation based on laboratory experience in making nanomaterials and experience garnered from colloid science suggest that the mobility of anthropogenic nanoparticles, and thus the potential for exposure, may often be small. Nonetheless, as in the case of toxicity, the relevance of our current experience in this domain is unclear. 

The field of nanogeoscience has recently emerged as a subdiscipline of the geosciences in response to the recognition that natural and anthropogenic nanoparticles,... 

Murr, L.E., Garza, K.M., Soto, K.F., Carrasco, A., Powell, T.G., Ramirez, D.A., Guerrero, P.A., Lopez, D.A., and Venzorlll, J. (2005) Cytotoxicity assessment of some carbon nanotubes and related carbon nanoparticle aggregates and the implications for anthropogenic carbon nanotube aggregates in the environment. International Journal of Environmental Research and Public Health, 2 (1), 31-42. 

Emission of nanoparticles in the atmosphere from anthropogenic sonrces (machines, aero engines, power stations, smelters, plasma, welding and heat treatment processes) has been continnonsly inaeasing ever since the beginning of the indnstrial revolntion. 

Nanoparticles originate from both natural and anthropogenic activities. This section provides a brief overview of the anthropogenically produced nanoparticles from gasoline and diesel-fuelled road vehicles, with a special focus on the emerging class of nanoparticles (i.e. ENPs). A brief overview of natural and anthropogenic sources is also presented for the completeness of the chapter. Wherever felt necessary, readers are directed to the relevant literature for detailed information. 

Nanoparticles produced from anthropogenic sources can either be formed inadvertently as a by-product of combustion activities (i.e. emissions from road vehicles and industries) or produced intentionally (e.g. ENPs) due to their particular characteristics [15]. The following section describes the ENPs in detail and provides only a brief overview of other anthropogenic sources. 

Other anthropogenic sources of nanoparticles can include brake and tyre wear [40], industrial emissions such as from power plants [86], idling, taxiing and... 

Airborne nanoparticles empirically fit well to log normal distributions and exhibit bimodal distributions in atmospheric urban environments. These arise from both natural and anthropogenic sources. Road vehicles remain a dominant source, contributing up to 90% of total PNCs, in polluted urban environments. 

Nanoparticles are not only a product of new nano-technologies, but are also present in the environment, and nanoscale phenomena permeate and often control natural processes.12 Humans have always experienced exposure to nanosized particles, but with the advent of the industrial revolution, this exposure from anthropogenic sources (e.g. internal combustion engines, power plant etc.) has increased dramatically. 

Zhang, R., L. Wang, A. F. Khalizov, X. Zhao, X. Zheng, R. L. McGraw and L. T. Molina (2009) Formation of nanoparticles of blue haze enhanced by anthropogenic pollution. Proceedings of the National Academy of Sciences of the United States of America 106, 17650-17654... 

Incidental nanoparticles are produced as a side product of anthropogenic processes such as in automobile exhausts. One interesting but unexpected source of incidental nanoparticles relates to the discovery that silver and copper metallic nanoparticles are formed spontaneously on the surface of manmade objects (made of Ag and Cu) that humans have long been in contact with and that macroscale objects represent a potential source of nanoparticles in the environment. 

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