Woodrow Wilson

The Project on Emerging Nanotechnologies is an initiative by the Woodrow Wilson Center and the Pew Charitable Trusts in 2005. As part of this initiative the Project has launched The Nanotechnology Consumer Products Inventory. This is the first online inventory of nanotechnology consumer products and contains some 212 manufacturer-identified nanoproducts. The inventory can be accessed online at www.nanoproject.org consumerproducts and at least some of the products and applications described here...

Secondary Particles

In addition to primary emitted particles there are also secondary particles in the atmosphere. Such particles are formed within the atmosphere itself from the condensation of low volatility vapours formed from the oxidation of atmospheric gases. Wholly new particles can be formed by a process known as homogeneous nucleation and relatively recent work has shown that in the presence of small concentrations of ammonia, sulfuric acid formed from the oxidation of sulfur dioxide is able to nucleate...

Source Strength of Traffic Particles

Various workers have sought to quantify the particle emissions from vehicles driving on the road. Such measurements have included the fine (PM2.5) fraction, assumed to arise mainly from engine exhaust, the coarse (PM2.5_10) fraction assumed to represent mainly abrasion sources (tyre, brake and road surface wear) and resuspended road dust, and the number of particles. Two main methods have been used - calculation from either concentration measurements made in tunnels with known ventilation...

Surface Area Concentrations

Measurements of particle surface area have been possible for some time using the BET method.30 However, it requires the collection of relatively large amounts of particles, and measurements are influenced by particle porosity (which may or may not be important) and collection support substrate -particularly where the quantity of material analysed is small. The first instrument designed specifically to measure aerosol surface area was the epiphaniometer.31 This device measures the Fuchs or...

References

Royal Society and Royal Academy of Engineering Nanoscience and nanotechnologies opportunities and uncertainties. The Royal Society, 2. A. Seaton, W. MacNee, K. Donaldson and D. Godden, Particulate air-pollution and acute health-effects, Lancet, 1995, 345, 176-178. 3. M.J. Utell and M.W. Frampton, Acute health effects of ambient air pollution the ultrafine particle hypothesis, Journal of Aerosol Medicine, 2000, 13, 355-359. 4. K. Donaldson, L. Tran, L. Jimenez, R. Duffin, D.E. Newby, N. Mills,...

Metal Oxides

The largest group of inorganic nanomaterials comprises metal oxides with titanium dioxide, zinc oxide and silicon dioxide as the largest volume materials. Copper oxide, cerium oxide, zirconium oxide, aluminium oxide and nickel oxide have also been produced commercially and are available in bulk. This category comprises the largest number of different types of nanomate-rials. Conducting an internet search for nanomaterial manufacturers generates many hits, with most of the companies identified...

Mass Concentration

Mass concentration measurements provide a link with current sampling conventions and methodologies for health-related aerosols. It is expected that the Occupational Exposure to Nanoparticles and Nanotubes 57 Table 1 Instruments and techniques for monitoring nanoaerosol exposure. The only devices offering a cut-point around 100 nm are cascade impactors (Berner-type low-pressure impactors or Microorifice impactors). Allows gravimetric and chemical analysis of samples on stages below 100 nm....

Free and Fixed Engineered Nanoparticles

Much of the recent speculation on the effects of engineered nanoparticles has focused on the free form, i.e. those not physically or chemically bound to larger structures. This has a certain logic given the relative mobility and ease of uptake into organisms of the free form. Nevertheless, the fixed form needs to be considered in aquatic systems because (a) the fixed form must have similar activity to the free form (or else it would not be useful commercially), (b) the fixed form may be...