2005 Fiscal Year Final Research Report Summary
ELUCIDATION OF GENERATION AND GROWTH MECHANISMS OF SECONDARY PARTICLES
| Project/Area Number |
14048216
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
OKUYAMA Kikuo Hiroshima University, Graduate School of Engineering, Professor, 工学研究科, 教授 (00101197)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMADA Manabu Hiroshima University, Graduate School of Engineering, Professor, 工学研究科, 教授 (70178953)
KODA Seiichiro Sophia University, Faculty of Science and Technology, Professor, 理工学部, 教授 (10011107)
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| Project Period (FY) |
2002 – 2005
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| Keywords | aerosol charging / homogeneous nucleation / ion-induced nucleation / mobility analyzer / uptake coefficient / carbon black / nanoparticle / particle size magnifier |
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| Research Abstract |
For assessment and prevention of the impact of secondary aerosol particles on atmospheric environment and human health, particle generation mechanism and methods for an accurate measurement of cluster ion and nanoparticles were investigated in this report.
1. MEASUREMENT OF AEROSOL SIZE DISTRIBUTION
In order to measure the particle size distribution of atmospheric aerosols from about 1nm to some microns, the differential mobility analyzer (DMA), mixing-type condensation nucleus counter (M-CNC), Faraday cup electrometer (FCE) were improved. Especially, combination of newly developed particle size magnifier (PSM) and conventional CNC made possible to measure number concentration of nanoparticles and ions down to 3nm in atmospheric and low pressure conditions. Moreover, in order to charge aerosol particles, alternative soft X-ray photoionizer was newly developed.
2. DEVELOPMENT OF THE CARBON-CONTAINING AEROSOL MEASURING METHOD
For an improvement of measuring technique for OC (organic carbon)
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and EC (elemental carbon) of aerosols, fundamental study for optical technique and comparison of OC concentrations with sampling methods were performed. For the improvement of carbonaceous particle measurement, standard filters with EC and OC reference particles were fabricated by a spray-drying method. The composite particles of SiO2/Carbon black were also prepared and the optical properties were also evaluated.
3. NUCLEATION AND GROWTH OF NANO-PARTICLES BY ION-INDUCED NUCLEATION
Experimental system, which consists of a drift tube ion mobility spectrometer/mass spectrometer and a cluster-DMA combined with FCE, was developed to investigate the relationship between cluster ions and nanoparticles. This system enabled mass spectrometric measurement of ions and high-resolution mobility spectrometric measurements of ions and ultrafine particles generated by ionizing radiation. Since gaseous pollutants have significant effects on atmospheric aerosol particle formation, effects of NO_2, one of main atmospheric gaseous pollutants, on particle formation in SO_2/H_2O/air mixtures irradiated by α-ray was experimentally investigated and relative importance of ion-induced nucleation to homogeneous nucleation was discussed. Less
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