Biomedical subjects

Guor-Cheng Fang

Publications and source records attributed to Guor-Cheng Fang.

At least 19 recordsLinked to original sources

PubMed2006

Overall dry deposition velocities of trace elements measured at harbor and traffic site in central Taiwan.

For reasonable and convenient assessments of the characteristics of the dry deposition velocities between Taichung harbor site and Wuchi town site in central Taiwan, the overall dry deposition velocities of several metallic elements were calculated as the particulate diameter (D(p)) distributions of large particles (D(p) > 10 microm), coarse particles (10 microm < D(p) < 2.5 microm), and fine particles (D(p) < 2.5 microm) based on the ambient measurements during March-December of 2004. In this work, the dry deposition fluxes showed the higher correlation with coarse particle concentrations than large particle concentrations; however, the least well correlation was observed between the dry deposition fluxes and the fine particle concentrations. The calculated best-fit overall dry deposition velocities obtained using coarse particle concentrations varied from approximately 0.2 cm s(-1) for Cr to 1.5 cm s(-1) for Pb and 0.2 cm s(-1) for Fe to 2.6 cm s(-1) for Pb at Taichung harbor and Wuchi town site, respectively. In general, the crustal elements had higher deposition velocities than anthropogenic elements. In addition, overall dry deposition velocities for crustal elements were higher in Wuchi town site than in Taichung harbor site. The results identified the dry deposition flux was mainly contributed from large and coarse particles due to their high deposition velocities. The results also indicated that the best approach to estimate overall dry deposition was by depending on the characteristics of particles with diameters larger than 2.5 microm.

Air Pollutants↗

PubMed2006

Study of ambient air particulates pollutants near Taichung airport sampling site in central Taiwan.

This study monitored the atmospheric pollutants at Taichung airport (TA) sampling site during September to December of 2005 near Taiwan Strait in central Taiwan. The distributions of the particle concentrations between the TSP, coarse and fine were also displayed at TA sampling site. Analysis the average percentage of various kinds of metallic elements, the data obtained here indicated that the average percentage concentrations of metallic elements Fe and Mg were higher in fine particulate than that of the coarse particulate at Taichung airport sampling site. These foundry factories were by the TA sampling site was the possible reason responsible for this result. In addition, by a non-parametric (Spearman) correlation analysis, the results indicated that Fe, Mn and Pb have high correlation coefficients of metallic elements in different particle size. The results indicate that the airport pollutants might come from similar pollutant sources at this airport sampling site. In addition, high correlation coefficients of non-airport pollutants were observed on the ionic species of SO(4)(2-), NH(4)(+) and K(+). The r(sp) correlate values between closed to r(sp)=0.7 and 0.9 at different particles size mode. Besides, the ionic Ca(2+) has high negative values (r(sp)=-0.66, -0.66 and 0.61) with the increasing of the temperature, relative humidity and wind speed, respectively at fine particle size.

Air Pollutants↗

PubMed2006

Atmosphic pollutants study of particles ionic species during high wind speed (>7 m s(-1)) near Taiwan strait in central Taiwan from 2004 to 2005.

This study monitored atmospheric pollutants during high wind speed (> 7 m s(-1)) at two sampling sites: Taichung Harbor (TH) and Wuci traffic (WT) during March 2004 to January 2005 in central Taiwan. The correlation coefficient (R (2)) between TSP, PM(2.5), PM(2.5-10) particle concentration vs. wind speed at the TH and WT sampling site during high wind speed (< 7 m s(-1)) were also displayed in this study. In addition, the correlation coefficients between TSP, PM(2.5) and PM(2.5-10) of ionic species vs. high wind speed were also observed. The results indicated that the correlation coefficient order was TSP > PM(2.5-10) > PM(2.5) for particle at both sampling sites near Taiwan strait. In addition, the concentration of Cl(-), NO(3) (-), SO(4) (2-), NH(4) (+), Mg(2+), Ca(2+) and Na(+) were also analyzed in this study.

Air Pollutants↗

PubMed2006

Influence of meteorological parameters on particulates and atmospheric pollutants at Taichung harbor sampling site.

Atmospheric aerosol particles and metallic concentrations, ionic species were monitored at the Experimental harbor of Taichung sampling site in this study. This work attempted to characterize metallic elements and ionic species associated with meteorological conditions variation on atmospheric particulate matter in TSP, PM2.5, PM2.5-10. The concentration distribution trend between TSP, PM2.5, PM2.5-10 particle concentration at the TH (Taichung harbor) sampling site were also displayed in this study. Besides, the meteorological conditions variation of metallic elements (Fe, Mg, Cr, Cu, Zn, Mn and Pb) and ions species (Cl(-), NO3 (-), SO4 (2-), NH4+, Mg2+, Ca2+ and Na+) concentrations attached with those particulate were also analyzed in this study. On non-parametric (Spearman) correlation analysis, the results indicated that the meteorological conditions have high correlation at largest particulate concentrations for TSP at TH sampling site in this study. In addition, the temperature and relative humidity of meteorological conditions that played a key role to affect particulate matter (PM) and have higher correlations then other meteorological conditions such as wind speed and atmospheric pressure. The parameter temperature and relative humidity also have high correlations with atmospheric pollutants compared with those of the other meteorological variables (wind speed, atmospheric pressure and prevalent wind direction). In addition, relative statistical equations between pollutants and meteorological variables were also characterized in this study.

Air Pollutants↗

PubMed2006

A review of atmospheric fine particulate matter and its associated trace metal pollutants in Asian countries during the period 1995-2005.

Many studies have monitored atmospheric particulates and gaseous phases of PM(2.5) in Asia over the past 10 years. This work also compared and discussed different sample collection, pretreatment and analytical methods in Asia countries in past decade. The results indicated that the main PM(2.5) sources are traffic exhausts. PM(2.5) concentrations are also ranked highest in the areas of traffic, followed by the urban sites, and lowest in rural sites in Asian countries. This work elucidates the sources, analytical tools, and the average concentrations for PM(2.5) and related metallic elements during 1995-2005. The results indicated that the average highest concentrations order of metallic elements for PM(2.5) were Fe>Mg>Zn, and the average concentrations of lowest metallic elements was Pb>Cu>Mn>Cr>Cd. The results also indicated that the concentration of metallic element Cu increased as the averaged concentrations of metallic element Zn and Mn increased during the past 10 years in Asian countries.

Air↗

PubMed2006

Characteristic study of dry deposition, concentration, compositions for particulates mass and ionic species during summer and autumn season at a traffic sampling site.

Aerosol samples for dry deposition and total suspend particulates (TSP) were collected from August to November of 2003 in central Taiwan. Ion chromatography was used to analyze the related water-soluble ionic species (Cl(-), NO(3)(-), SO(4)(2-), Na(+), NH(4)(+), K(+), Mg(2+) and Ca(2+)). The results obtained in this study indicated that the ambient air particulate mass concentrations in the daytime period (averaged 975.4 microg m(-3)) were higher than the nighttime period (averaged 542.1 microg m(-3)). And the daytime dry deposition fluxes (averaged 58.12 microg m(-2) sec(-1)) were about 2.2 times as that of nighttime dry deposition fluxes (averaged 26.54 microg m(-2) sec(-1)) of the downward dry deposition. The average values downward and upward of dry deposition fluxes for the weekend period were almost higher than the weekday period for either daytime or nighttime period. Furthermore, the average daytime dry deposition fluxes (averaged 26.37 microg m(-2) sec(-1)) were also about 2.3 times as that of nighttime dry deposition fluxes (averaged 11.52 microg m(-2) sec(-1)). Moreover, the results also indicate that SO(4) (2-) and Ca(2+) have higher average composition for total suspended particulates in the daytime period while Ca(2+), SO(4) (2-), and Na(+) have the higher average composition for total suspends particulates in the nighttime period.

Air Pollution↗

PubMed2006

Source identifications of PM10 aerosols depending on hourly measurements of soluble components characterization among different events in Taipei Basin during spring season of 2004.

Continuous measurements of hourly PM10 soluble ions were performed by the in situ IC technology in order to assess the impact of Asian outflows on local air quality. The intensive aerosol observation was carried in Taipei from 11 February 22:00 to 7 April 19:00, 2004. Concentrations of the water-soluble ions (Cl(-), NO(-)(2), NO(-)(3), SO(2-)(4), Na(+), NH(+)(4), K(+), and Ca(2+)) were measured in a total of 3,300 samples. The characteristics of air pollutant events in Taipei Basin were classified as frontal dust, dust, northeast monsoon, south wind and sea/land breeze according to the hourly meteorology and air pollutant concentrations. Factor analysis was conducted based on hourly data for 13 variables to find the group of variables with similar behavior. According to the source characteristics of high loading species, the possible sources of PM10 aerosols in each group were identified. Three to four factors were identified for each event. The total variances of frontal dust, dust, northeast trade, south wind, and sea/land breeze events were explained about 85%, 86%, 76%, 77%, and 80%, respectively, indicating that the identified factors were satisfactory.

Aerosols↗

PubMed2006

Apply appropriate statistic methods in analyzing ambient air particulate and metallic elements concentrations at a traffic sampling site.

A study of the characteristics of the metallic elements concentrations in fine and coarse particulates at traffic sampling site in central Taiwan by using appropriate statistical analysis methods was described in this paper. The Spearman correlation analysis and non-linear regression analysis were used to analyze the collected data during sampling period from August 2003 to March 2004. During a half-month analysis periods, the average metallic elements concentrations, the major meteorological effects and temporal variation were discussed in this study. The major meteorological parameters during daytime and nighttime sampling periods are temperature, average wind velocity and prevailing wind degree. The relationships between the metallic elements concentrations and meteorological parameters in fine and coarse particulates during daytime and nighttime are also established in this paper. According to the proposed equations, the variation of the particle concentrations can be predicted with known meteorological parameters during daytime and nighttime at traffic sampling site in central Taiwan.

Air Pollutants↗

PubMed2006

Ambient air particulate concentrations and metallic elements principal component analysis at Taichung Harbor (TH) and WuChi Traffic (WT) near Taiwan Strait during 2004-2005.

The purpose of this study is to characterize metallic elements associated with atmospheric particulate matter of total suspended particulate (TSP), fine particle (particle matter with aerodynamical diameter <2.5 microm, PM(2.5)), coarse particle (particle matter with aerodynamical diameter 2.5-10 microm, PM (2.5-10)) at the Taichung Harbor (TH) and WuChi Traffic (WT) sampling site of central Taiwan during March 2004 to February 2005. The result indicated the average total suspended particulate concentration in 1 year was 157.31 and 112.58 microg m(-3) at TH and WT sampling site, respectively. Fine particle (PM(2.5)) size was the dominant species at TH and WT sampling site. In TH sampling site, higher correlation coefficient was observed on total suspended particulates of metallic elements Fe and Zn. And in WT sampling site, higher correlation coefficients displayed on total suspended particulates of metallic elements Fe and Zn, Fe and Mn. Ambient airborne particle principal component analysis of metallic metals was used to identify the possible pollutant sources in this study. At the TH sampling site, 50.81% of the total variance of the data was observed in factor 1. Higher loading of Fe (0.86), Zn (0.79), Pb (0.76), and Mn (0.68) were contributed by traffic emission and the soil source. At the WT sampling site, factor 1 explained 53.74% of the total variance of the data and had high loading for Zn (0.86) and Cu (0.85), which were identified as industrial/traffic emission sources.

Air↗

PubMed2006

Dry deposition, ionic species measured and source interpretation during seasonal cycle at offshore areas near Taiwan Strait.

The characterization for water-soluble species of total suspended particulate (TSP), dry deposition flux, and dry deposition velocity (V(d)) were studied at Taichung Harbor (TH) and Wuchi traffic sampling sites at offshore sampling site near Taiwan Strait of central Taiwan during March 2004-January 2005. The average concentrations of TSP and dry deposition flux at the TH sampling site were higher than at the WT sampling site during the sampling period. The samples collected were analyzed by a ion chromatography (DIONEX-100) for the ionic species (Cl(-), SO(4)(2-), NO(3)(-), NH(4)(+), Na(+), Ca(2+), and Mg(2+)) analysis. The dominant ionic species for TSP are SO(4)(2-), NO(3)(-), and NH(4)(+) of the total mass of the inorganic ions at both sampling sites. In addition, the results indicated that the NH(4)(+), NO(3)(-) and SO(4)(2-) showed higher concentrations in winter and lower in summer for both TH and Wuchi sampling sites. Statistical methods such as correlation coefficient and principal component analysis were also used to identify the possible pollutant source.

Air Movements↗

PubMed2006

A study of polycyclic aromatic hydrocarbons concentrations and source identifications by methods of diagnostic ratio and principal component analysis at Taichung chemical Harbor near Taiwan Strait.

Fine (PM(2.5)) and Coarse (PM(2.5-10)) particulates concentrations of ambient air particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously from February 2004 to January 2005 at the Taichung Harbor (TH) sampling site near Taiwan of central Taiwan. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on quartz filters, the collected sample used soxhlet analytical method extracted with a dichloromethane (DCM)/n-hexane mixture (50/50, v/v) for 24h, and then the extracts were subjected to gas chromatography-mass spectrometric (GC-MS) analysis. The results indicated that vehicle emissions, coal combustion, incomplete combustion and pyrolysis of fuel and oil burning were the main source of PAHs near Taiwan Strait of central Taiwan. Diagnostic ratio and principal component analysis (PCA) were also used to characterize and identify PAHs emission source in this study.

Air Pollutants↗

PubMed2006

Atmospheric pollutants study of particles and metallic elements during high wind speed (wind speed >6 m/s) near Taiwan Strait around central Taiwan.

The purpose of this study was to characterize metallic elements associated with atmospheric particulate matter in total suspended particulate (TSP), fine particles (particle matter with an aerodynamic diameter of <2.5 microm, PM2.5) and coarse particles (particle matter with an aerodynamic diameter of 2.5-10 microm, PM2.5-10), at high wind speed (wind speed >6 m/s) at Taichung Harbor (TH) and Wuci traffic (WT) in central Taiwan from March to December 2004. The correlation coefficient (R2) between TSP, coarse, fine particulate concentrations versus wind speed at the TH and WT sampling site during high wind speed (>6 m/s) are shown in this study. In addition, the correlation coefficients between TSP, coarse and fine particles of metallic species versus high wind speed were also observed. The results indicated that the correlation coefficient order was TSP> coarse>fine for particles at both sampling sites during high wind speed (>6 m/s) near central Taiwan. In addition, the concentrations of Fe, Zn, Mn, Cu, Pb, Cr, Mg for TSP, coarse and fine particulates were also analysed in this study.

Air Pollutants↗

PubMed2006

Characteristic study of ionic species in nano, ultrafine, fine and coarse particle size mode at a traffic sampling site.

A micro-orifice uniform deposit impactor (MOUDI) and a nano-MOUDI were used to measure the atmospheric coarse (PM2.5-10), fine (PM2.5), ultrafine (PM0.056-1) and nano (<0.056 microm) particle concentrations at a traffic sampling site in central Taiwan during the winter period from November 2004 to January 2005. Meanwhile, concentrations of major ionic species (Cl-, NO3-, SO(2-)4, NH4+, Na+, K+, Ca2+ and Mg2+) were also extracted from various particle size modes (nano, ultrafine, fine and coarse) and analysed by ion chromatography (DIONEX-100). The mass size distribution of ambient suspended particles exhibited two modes. The size ranges of the particles at these two particle size modes were between 1.0 and 1.8 microm and 3.2 and 5.6 microm, respectively. The average mass media aerodynamic diameter (MMAD) of suspended particles was 0.99 microm in this study. In addition, statistical methods, such as correlation coefficient and principal component analysis, were also used to identify the possible pollutant source for various particles size modes (nano, ultrafine, fine and coarse) during the winter months at a traffic sampling site in central Taiwan.

Air Pollutants↗

PubMed2006

Seasonal variation in concentration and metallic constituents of atmospheric particulates near the western coast of central Taiwan.

In addition to determining the concentration and metallic constituents of particulate matter at Taichung Harbor in central Taiwan, this study attempts to characterize the mass, metallic elements, composition and concentrations of total suspended particulates (TSP), fine particles and coarse particles. Statistical approaches, such as the Spearman tests, were also adopted to determine the seasonal variations of concentrations of these pollutants. Experimental results indicate that the mean TSP, fine particulate and coarse particulate concentrations in spring and winter are higher than in summer and autumn on the western coast of central Taiwan. Spearman statistical analysis of metallic elements Mn and Pb showed high concentration coefficients for fine and coarse particulates on the western coast of central Taiwan. The order of mean metallic concentrations in TSP, coarse particulates and fine particles was Fe > Zn > Mg > Cu> Cr > Mn > Pb in TSP, Fe > Cu > Zn > Mg > Mn > Pb > Cr in coarse particulates and Fe > Cu > Mg > Pb > Zn > Mn > Cr in fine particulates.

Air Pollutants↗

PubMed2005

Atmospheric polycyclic aromatic hydrocarbons (PAHs) in Asia: a review from 1999 to 2004.

Polycyclic aromatic hydrocarbons (PAHs) are present in both gaseous and particulate phases. These compounds are considered to be atmospheric contaminants and are human carcinogens. Many studies have monitored atmospheric particulate and gaseous phases of PAH in Asia over the past 5 years. This work compares and discusses different sample collection, pretreatment and analytical methods. The main PAH sources are traffic exhausts (AcPy, FL, Flu, PA, Pyr, CHR, BeP) and industrial emissions (BaP, BaA, PER, BeP, COR, CYC). PAH concentrations are highest in areas of traffic, followed by the urban sites, and lowest in rural sites. Meteorological conditions, such as temperature, wind speed and humidity, strongly affect PAH concentrations at all sampling sites. This work elucidates the characteristics, sources and distribution, and the healthy impacts of atmospheric PAH species in Asia.

Air Pollutants↗

PubMed2005

Characteristic of polycyclic aromatic hydrocarbon concentrations and source identification for fine and coarse particulates at Taichung Harbor near Taiwan Strait during 2004-2005.

Fine (PM(2.5)) and coarse (PM(2.5-10)) particulate concentrations of ambient air polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously from February 2004 to January 2005 at the Taichung Harbor (TH) sampling site near Taiwan of central Taiwan. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on quartz filters; the collected sample was Soxhlet extracted with a dichloromethane (DCM)/n-hexane mixture (50/50, v/v) for 24 h, and then the extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). The results indicated that vehicle emissions, coal combustion, incomplete combustion and pyrolysis of fuel and oil burning were the main source of PAHs near Taiwan Strait of central Taiwan. Diagnostic ratios and principal component analysis (PCA) were also used to characterize and identify PAHs emission sources in this study.

Air Pollutants↗

PubMed2005

Characterization of atmospheric particulate and metallic elements at Taichung Harbor near Taiwan Strait during 2004-2005.

Air aerosol samples for TSP (total suspended particulate), coarse particulate (particle matter with aerodynamical diameter 2.5-10 microm, PM(2.5-10)), fine particulate (particle matter with aerodynamical diameter <2.5 microm, PM(2.5)) and metallic elements were collected during March 2004 to January 2005 at TH (Taichung Harbor) in central Taiwan. The seasonal variation average concentration of TSP (total suspended particulate), coarse particulate (particle matter with aerodynamical diameter 2.5-10 microm, PM(2.5-10)) and fine particulate (particle matter with aerodynamical diameter <2.5 microm, PM(2.5)) were in the range 132-171.1 microg m(-3) and 43-49.5 microg m(-3), respectively. Seasonal variation of metallic elements Cu, Mn, Zn and Fe in the TSP (total suspended particulate) shows that higher concentration was observed during spring. Seasonal variation of metallic elements Pb, Cr and Mg in the TSP (total suspended particulate) shows that higher concentration was observed during winter. The average metallic element TSP (total suspended particulate) concentration order was Fe>Zn>Mg>Cu>Cr>Mn>Pb in spring. In addition, at the TH sampling site, the average concentration variation of TSP (total suspended particulate) displayed the following order: spring>winter>autumn>summer. However, the average concentration variation of coarse particulate (particle matter with aerodynamical diameter 2.5-10 microm, PM(2.5-10)) displayed the following order: spring>winter>summer>autumn. Finally, the average concentration variations of fine particulate (particle matter with aerodynamical diameter <2.5 microm, PM(2.5)) were in the following order: winter>spring>summer>autumn at the TH sample site.

Air Pollutants↗

PubMed2005

Concentrations of ambient air particulates (TSP, PM2.5 and PM2.5-10) and ionic species at offshore areas near Taiwan Strait.

The concentrations of total suspended particulate (TSP), fine particles PM(2.5) (with aerodynamic diameter <2.5 microm), coarse particles PM(2.5-10) (with aerodynamic diameter 2.5-10 microm,), and water-soluble inorganic ions were studied at two offshore sampling sites, Taichung Harbor (TH) and Wuci Traffic (WT), near Taiwan Strait in central Taiwan during March 2004 to January 2005. Statistical analyses were also carried out to estimate the possible sources of particulate pollution. Experimental results showed that the average mass concentrations of TSP, PM(2.5) and PM(2.5-10) at TH and WT sampling sites were 154.54 +/- 31.45 and 113.59 +/- 31.94 microg m(-3), 54.03 +/- 16.92 and 42.76 +/- 12.52 microg m(-3), and 30.31+/- 9.79 and 24.16 +/- 7.27 microg m(-3), respectively. The dominant inorganic ions at two sampling sites were SO(4)(2-), NO(3)(-), and NH(4)(+) for TSP and PM(2.5), but that were Ca(2+), Cl(-), and Na(+) for PM(2.5-10). The concentrations of most particulates and inorganic ions were higher in winter at both two sampling sites, and were higher at TH than WT sampling site in each season. From statistical analysis, air-slake of crust surface, sea-salt aerosols, agriculture activities, coal combustion, and mobile vehicles were the possible emission sources of particulate pollution at TH and WT sampling sites.

Agriculture↗