Ambient particles (PM10-2.5、PM2.5、PM0.18-0.1、PM0.1-0.056及PM0.056) were studied at the road side of Poai Street and in the Eighteen-Peak mountain in Hsinchu, in the Syueshan high-way tunnel in Taipei, in the Experimental Forest of NTU in Nan-Tou and a TiO2 powder manufacturing factory in Kaohsiung, Taiwan, using a TSI model 3936 SMPS, two MOUDIs (MSP Model 110) and two Dichots (Thermo Scientific SA 241) in parallel. As well as particle size distribution, chemical compositions were analyzed by ICP-MS for elements, ion chromatograph for ions and Thermo-Optical Reflection (TOR) method for OC and EC. The road side sampling showed similar results with those of Cass et al. (2000) who measured the mass concentration of nanoparticles at seven urban areas in California. The average concentration of two road side sampling was 1.5 mg/m3. The high-way tunnel sampling and real-time measurement showed the concentration of nanoparticles at day time was 20-40 mg/m3 while it decreased to 5-15 mg/m3 at night time. Nanoparticle concentration of the NTU experimental forest was as low as 0.99 mg/m3 (MOUDI). Meanwhile from the real-time concentration distribution (SMPS) of nanoparticles, it is concluded that the NTU Experimental Forest is a specific biogenetic source of nanoparticles. Similar and low concentrations of nanoparticle were observed at the ambient and workplace of the TiO2 powder factory, indicating that nanoparticle emission was not severe. Chemical analysis showed ions were the most abundant species at the road side and the eighteen-peak mountain. The first two high-way tunnel samplings (before 2008/11/15) showed that OC was the most abundant component while the third and fourth tunnel samplings showed the most abundant species was EC. This was mainly due to the admission of bus driving in the tunnel from Nov. 15, 2008 and an substantial increase of diesel vehicles after that. Ions were the main component of nanoparticles in the forest, on the other hand the proportion of OC was only 11.3 %. This value indicates the OC might have been underestimated. This study also reviewed the latest papers about ten nanotechnolgy knowledge gaps, including the measurement methods of environmental nanoparticles, the protection instrument and equipment of manufactured nanomaterials, and developing the assessment methods of the toxicity of manufactured nanomaterials in water, etc. On the ten topics, ten seminars were held and the comments from the attending experts were collected. We summaried the suggestions in this report both on the technical and policy aspects of the nanotechnology knowledge gaps. It is hoped this report is useful to the agencies concerned with nanotechnogy EHS.

sampling of nanoparticle,component analysis of nanoparticle,measurement of nanoparticle concentration