As nanotechnology comes to be used on a wider basis in industry, engineered nanoparticles will also begin to be produced in ever greater numbers. Given the possibility that nanoparticles, by their nature, will interact with the environment, humans, animals, and plant life differently that the more bulky forms used in industry now, estimating how many nanoparticles there are has begun to take on greater importance.

"Estimates of Upper Bounds and Trends in Nano-TiO2 Production as a Basis for Exposure Assessment" published online by Environmental Science and Technology, (for a short summary of the paper, please read "Engineers attempt to count nanoparticles in the environment" from R&D Magazine), tries to estimate the current and future production of Nano-TiO2 particles.

While recent studies have estimated environmental TiO2 exposure based on release from end use life cycles. . .  our approach looks further upstream in the life cycle to create upper limits of nano-TiO2 exposure, identifying how much nano-TiO2 may be produced prior to incorporation in end use products. Three pieces of information are necessary to project sources of nano-TiO2 exposure over time: current nano-Ti)2 production volumes must be know to proviade a baseline or y-intercept of our projection function; the maximum potential production volume is considered here as the total TiO2 market, . . . and the growth rate over time (slope) must be estimated to describe how the production magnitude might increase from the baseline toward the maximum potential level. This work estimates these values.

The results of this study may be a bit flawed, since the companies that produce, use or import nano-TiO2 treat that information as proprietary.

Why is it important to have an estimate of how much nano-Ti02 and other nanoparticles the environment, workers, and consumers are exposed to?

With the growth of nanotechnology, engineered nanoparticles are produced and incorporated into products and processes across a broad spectrum of industries and will inevitably enter the environment. The novel properties resulting from their nanoscale size . . . may also cause nanomaterials to interact with the environment and living organisms in ways that may differ from their bulk scale counterparts. . . . Assessing the impacts and risks posed by nanomaterials requires estimates of potential environmental exposure to their materials. In turn, an understanding of the variety and physical magnitude of nanomarticle sources is the starting point for estimating environmental exposure to nanomaterials and interpreting exposure predictions for the purposes of formulating possible regulation and risk management strategies. Relevant exposure estimates are particularly urgent for those materials already finding their way into industrial and consumer products.

If the expectations regarding nanotech becoming significantly more prominent in the near future are realized, any potential negative impacts may have enourmous medical, economic, legal and policy related effects. In the face of certain growth and such uncertain effects, it is essential to produce toxicity and exposure risk assessments for nanomaterials, even if they begin as approximations, to frame the issue and understand the size of the potential problem.