Nanotechnology is the core scientific tool that is indispensable for enabling non-linear evolution in various technological fields and settlement of pressing issues such as energy/environmental and life science. Strategic investment on nanotechnology R&D is in place, but commercialization of nanotechnology R&D shows little progress. A comprehensive approach encompassing societal implication of nanotechnology becomes much more important for addressing this situation. Since the publication of papers on hazard identification of carbon nanotube (CNT), environmental, health, and safety (EHS) issues have become crucial among the regulatory bodies around the world. But societal implication involves more than EHS issue, such as standardization and Intellectual Property issues. As a result, necessary information to address societal implication of nanotechnology is enormous. We carry out gleaning information which is relevant to the societal implication and provide it to the stakeholders. We are about to start an online portal information sharing system. We support commercialization of core nanotechnology R&D outcomes with the practical use of the system.
Although it is very important to characterize manufactured nanomaterials in order to estimate the harmful effect of the nanomaterials, there is little research on the characterization in the world. The characterization of nanomaterials with a well-dispersed state was accompanied by New Energy and Industrial Technology Development Organization (NEDO) project in Japan, and animal exposure studies to well-characterized nanomaterials have been performed. We have reviewed the harmful effect of nanomaterials mainly based on NEDO project. There are no consistent data on cytotoxicity of fullerene in vitro study, but the animal exposure studies including NEDO project showed that fullerene either induced transient inflammation in the lung or no induction. Based on these results, we suggested that fullerene may not have high potentials with inflammation and fibrosis. Single and multi walled carbon nanotube induced cytotoxicity in vitro study and acute inflammation in animal model. Intratracheal instillation study of multi-walled carbon nanotube in NEDO project also induced acute inflammation in lung of rat. These data suggested that carbon nanotube may have potentials to inflammation. However, it is important to examine the chronic effect such as chronic inflammation, fibrosis and cancer in animal study in order to estimate harmful effect of carbon nanotube. Therefore we expect to come out with new data and research on the chronic effect of carbon nanotube in the future.
Documentary standards related to measurements of aerosols, including those of engineered nanoparticles, that are developed in ISO are explained in this article. Those standards are developed in Subcommittee 4 of Technical Committee 24 (TC 24/SC 4 : Particle characterization) and Technical Committee 229 (TC 229 : Nanotechnologies). This article explains the purpose, scope, target users, and the current development status of the standards, and who are involved in the development.
This article explains the light scattering aerosol spectrometer, which is one class of optical particle counters. Exposure level of workers to airborne nanoparticles in the working environment is sometimes evaluated investigated with a set of a condensation particle counter (CPC) and an optical particle counter (OPC). However, since many OPC are designed for measurements of low particle concentrations such as those in a clean room the counting of OPC is often saturated and does not provide accurate particle concentrations for the measurements of atmospheric or workplace aerosols measurements. A few OPCs can operate at high concentrations, and the aerosol spectrometer is one of them. In this article, the measurement principle and a typical instrument design are explained along with the contents of the new ISO standard 21501-1 for the aerosol spectrometer.
The exposure measurement of nanomaterial aerosol is important in risk management, and there exist several problems for conducting quantitative measurement of nanomaterials in workplace air. In the present paper, we introduce several problems we are now facing at the real workplace. From our experience, the exposure measurement needs three steps, i.e., pre-survey, preliminary survey and further survey. The pre-survey includes understanding the work processes, materials handled in the workplace and probable emission sources. At the preliminary survey, emission sources are identified by portable particle counters. Characterization of particles by size distribution measurement and electron microscopic observation, and quantitative measurement by chemical analysis are conducted at the further survey. At present, an appropriate combination of several metrics should be selected in order to evaluate the workplace environment.
Recently, toxicological studies on health effects related to aerosol exposure suggest that nanoparticles (particles with diameter less than 100 nm) may cause health effects after their inhalation. It is necessary to consider protective measures against inhalation of the nanoparticle aerosols. In this paper, we overview the performance of fibrous air filters for nanoparticles and selection process of personal protective equipments, such as dust respirators, at the workplaces where workers handle any nanomaterials.
The present work studied the photocatalytic degradation of VOC gas by a mist formed by ultrasonic nebulization of TiO2 suspension with various wave lengths of UV rays. With UV365 irradiation, toluene was decomposed by photocatalytic reaction either on the mist surface or inside it. The toluene removal efficiency increased with the TiO2 concentration of the suspension. Water-soluble intermediates formed by the decomposition of VOC gases were completely trapped in the mist and were not detected at the reactor exit. Under UV254+185 irradiation, the complete decomposition efficiency to CO2 and H2O was higher than that with UV365 or UV254 irradiation. With UV254+185 irradiation, it was found that VOC gases were immediately degraded and converted to water-soluble intermediates by not only direct photolysis but also oxidation by OH radicals, because the removal rate of several organic gases depended on the reaction rate with OH radicals. On the other hand, ozone mainly contributed to complete decomposition of intermediates, because the complete decomposition efficiency of intermediates was decreased without ozone generation under UV254+185 irradiation in N2. Finally, we proposed the degradation mechanisms of organic gaseous pollutants on the mist surface.
Community aerosol inlet is designed for the super sites of SKYNET ground monitoring network in accordance with the guideline proposed by World Meteorological Organization/Global Atmosphere Watch project. The basic structure of this GEOSS-SKYNET inlet consists of a vertical pipe installed through the roof of the laboratory so that air is brought from the inlet top (>4.5 m from the ground level) to the iso-kinetic air splitter attached at the bottom of pipe with minimal bending. Aerosols are pre-separated at the inlet top with PM10 impactor head which is newly designed for SKYNET super sites. The size separation characteristic of the inlet is tested with poly-dispersed fly-ash particles in a factory. The fly-ash particles collected on Nuclepore filters in the experiment were counted with Coulter counter method in 300 size bins. The obtained 50 % cut-off particle diameter of the inlet is 6.65 μm, which corresponds to 9.4 — 10.3 μm in aerodynamic diameter. Although the size separation characteristic of the inlet deviates from that of single-jet impactor with flat impaction plate in low Stokes Number region, it has better performance than commercially available PM10 inlets in the region of relatively small Stokes number.