This study continuously conducted ambient aerosol sampling at three Taiwan air monitoring stations (TAMSs), namely Sinjhuang, Jhongshan, and Judong stations. The sampling data were also incorporated with those from previous project for analyzing the seasonal variation of particle size distribution, mass concentration, composition of water-soluble ions, and metal compositions, etc. for each station.
Measurement difference between the PM2.5 concentrations measured by the dichotomous sampler (PM2.5,D) and those by the beta attenuation monitor (BAM, PM2.5,B) which is used in the TAMS was also investigated. Results show that the major reason for the systematic overestimation of PM2.5,B is the positive artifact due to acid gases adsorption by the glass fiber filter tape used by the BAM. It is suggested that the current non-FEM-designated BAMs used in the TAMS should be replaced by those with FEM designation or the glass fiber filter tapes used in the BAM should be replaced by those made by the material which is inert to acid gases adsorption such as Teflon filter.
In order to evaluate the PM2.5 measurement difference between manual samplers and real-time monitors and to investigate the sampling artifacts of traditional filter-based samplers, a home-made multi-filter PM10-PM2.5 sampler (MFPPS) was collocated with the commercial available manual samplers (Dichot and WINS PM2.5 sampler) and a tapered element oscillating microbalance-filter dynamic measurement system (TEOM-FDMS) at National Chiao Tung University (NCTU) campus and Judong air monitoring station for sampling comparison. Results show that the evaporation loss is severe during sampling process for filter-based sampler, and is increases with an increasing filter face velocity and a decreasing particle loading amount on the filter. For these two sampling sites, the major volatile components were found to be inorganic species, while the evaporation loss in organic matter was insignificant. The results of the comparison between TEOM-FDMS and manual samplers show that the former is able to correct sampling artifact and therefore to provide an accurate PM2.5 measurement. Hence, the standard operation procedure of the TEOM-FDMS was also edited in a hope to provide a reference to the community who intends to apply the TEOM-FDMS in the future.
For the assessment of nanoparticle emission during the use of nanoparticle incorporated products, it is found that for the three commercial available Ag-socks tested in this study, both the number concentration of nanoparticles emitted into the air and the amount of metal released into the water decreased after they have been washed. The Ag amounts contained in different parts of the sock were also measured, in which the toe part was found to have the highest amount. Among these three types of socks tested in this study, only the one listed in the Project on Emerging Nanotechnologies (PEN) web site was found to have a significant Ag amount (567.98 μg Ag / g sock) in the toe part of the sock, and its antibacterial ability was found to be good. However, the other two types of socks, one has the Taiwan nano-mark and the other has none, were found to have a very little Ag amount (2.74 and 7.82 μg Ag / g sock), and their antibacterial ability were found to be poor.
Finally, the feasibility of quantifying the metal concentration in ambient aerosol sample by the technique of using the Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to analysis the internal standard sample was also evaluated. Results show that the calibration curves of most of the metal elements have good correlation (R2 > 0.9), and the results from different tests are stable. This technique was further validated by analyzing the aerosol sampler collected in Syueshan highway tunnel. Results show that this technique is able to analyze the metal elements in aerosol sample efficiently and quickly. It is expected that the LA-ICP-MS technique can be used to measure the time-varying metal concentration with a short time interval.