Biomedical subjects

Guor-Cheng Fang

Publications and source records attributed to Guor-Cheng Fang.

41 records · Page 3Linked to original sources

PubMed2002

Estimating the frequency distributions of PM10 and PM2.5 by the statistics of wind speed at Sha-Lu, Taiwan.

The frequency distribution of air pollutant concentration varies with the meteorological conditions and pollutant emission level. There exists a simple relation between the frequency distribution of wind speed and frequency distribution of air pollutant concentration. The concentration of air pollutant, C, at cumulative probability, p, is inversely proportional to the wind speeds, u, at probability of (100 - p) when the distributional types and shape factors of both data are the same. The relationship is shown as K=Cp u(100 - p), where K is constant. In this study, three theoretical distributions (log-normal, Weibull and type V Pearson distributions) are selected to fit the measured data of PM10, PM2.5 and wind speed. The frequency distributions of air pollutants can be estimated from the simple relationship of air pollutant concentration and wind speed. The results show that the log-normal distribution is the best one to represent the data of PM10, PM2.5 and wind speed. The K values of PM10 and PM2.5 are nearly constant from the 30-80th percentiles. It was also found that the distributions of PM10 and PM2.5 can be successfully estimated from the distribution of wind speed. The Kolmogorov-Smirnov (K-S) test shows that there is no significant discrepancy between the estimated and measured distribution of PM10 and PM2.5 at the 95% confidence level. Therefore, the distribution of air pollutants is easily estimated when the wind speed data are known.

Air Pollutants↗

PubMed2002

The measurements of ambient particulates (TSP, PM2.5, PM2.5-10), chemical component concentration variation, and mutagenicity study during 1998-2001 in central Taiwan.

During June 1998 and February 2001, the experiments of this study were conducted at four sampling sites (THUPB, THUC, HKIT and CCRT) with different characters (suburban, rural and traffic). The chemical components (Cl-, Na+, K+, Mg2+, Ca2+, Fe, Zn, Pb, Ni) in suspended particle were also analyzed simultaneously. The particulate mass concentrations are higher in the traffic site (CCRT) than the other sampling sites in this study. This is because that high traffic density flow characterized CCRT sampling site. Besides, the fine particle (PM2.5) concentration was the dominant species out of the total suspended particles in central Taiwan, Taichung. The same phenomenon is found in most of cities around the world. Moreover, chloride, nitrate sulfate and ammonium are higher in Taiwan than other sampling sites in the world. The results also indicated that the control of acidic and secondary aerosol pollutants have become an important issue in Taiwan. In addition, mutagenic assays on the organic extracts of airborne particulates at different sampling sites were also conducted in central Taiwan. The data obtained here also reflected that the mutagenicity of the suspended particulates are significantly higher in winter period than it occurred in summer period.

Air Pollutants↗

PubMed2002

Emission characters of particulate concentrations and dry deposition studies for incense burning at a Taiwanese temple.

Suspended particulate concentrations were measured at the Tzu Yun Yen temple in the Taichung region of Taiwan. The temple performs traditional incense burning. A universal sampler and a micro-orifice uniform deposited impactor (MOUDI) sampler with a dry deposition plate were used to measure the particulate concentrations. The results show that the average PM2.5/PM10 ratio was 74% during the incense burning period at this temple. In addition, the average suspended particulate (PM10) element concentration of anthropogenic element Zn (495 ng/m3) was higher than the other anthropogenic elements (Pb, Mn, Ni, and Cd). Furthermore, the average mass size distribution was bimodal with major peaks occurring at 0.32-0.56 microm and 5.6-10 microm during the incense burning period. The dry deposition velocities of Cd used fine particulates (PM2.5) and suspended particulate (PM10) mode were 1.86 and 0.99 cm/s in this study, respectively.

Air Pollution, Indoor↗

PubMed2002

Toxic equivalency factors study of polycyclic aromatic hydrocarbons (PAHs) in Taichung City, Taiwan.

Airborne particles and polycyclic aromatic hydrocarbons (PAHs) in industrial, background and urban atmosphere environments were investigated using toxic equivalent factors (TEFs) in central Taiwan during the period of August-December 2002. Concentrations of airborne particles were 93.4, 81.3 and 102.4 microg/m3 for industrial, background and urban sites, respectively. Concentrations of 21 gaseous PAHs were 1530, 759 and 1030 ng/m3 for industrial, background and urban sites, respectively; for carcinogenic activity of gaseous PAHs, the benzo[a]pyrene (BaP) equivalent concentrations were 17.0, 7.29 and 12.6 ng/m3 for industrial, background and urban sites, respectively. Twenty-one particle-bound PAHs were only 10% of the 21 gaseous PAHs. Dibenzo(a,h)anthracene (DBA) serves as a surrogate to explain the carcinogenic activity of PAH mixtures in central Taiwan because its carcinogenicity is a high percentage of the total carcinogenic activity. During the sampling period, temperature inversion from a cold front from China occurred, leading to average daily temperatures of 16 degrees C. These cold fronts caused atmospheric particles and pollutants to accumulate in the troposphere, leading to extremely high concentrations of airborne particles and both gaseous and particle-bound PAHs in central Taiwan.

Air Pollutants↗

PubMed2002

Dry deposition (downward, upward) concentration study of particulates and water-soluble ionic species during daytime, night-time period at the traffic sampling site of Sha-Lu, Taiwan.

Ambient suspended particulate (dry deposition, TSP) was collected in the traffic sites Sha-Lu, central Taiwan. In addition, the related water-soluble ionic species (Cl-, NO3(-), SO4(2-), Na+, NH4(+), K+, Mg2+ and Ca2+) were analysed and wind speed, wind direction and temperature were also measured in this study. The downward dry deposition fluxes (averaged 54.07 microg/m2-sec) were about twice that of upward dry deposition fluxes (averaged 26.48 microg/m2-sec) in the daytime period. Furthermore, the average downward dry deposition fluxes (averaged 26.22 microg/m2-sec) were also about twice that of upward dry deposition fluxes (averaged 12.11 microg/m2-sec) in the night-time period. The results showed that the total suspended particulate concentrations of particulate mass in the daytime period (averaged 996.2 microg/m3) were higher than in the night-time period (averaged 560.7 microg/ m3). The results showed that the total suspended particulate concentrations of particulate mass in the daytime period (averaged 996.2 microg/m3) were higher than in night-time period (averaged 560.7 microg/ m3). As for water-soluble ionic species, the average dry deposition order and velocity for downward ionic species were Cl- > Ca2+ > NO3(-) > K+ (2.09 cm/sec > 1.46 cm/sec > 1.46 cm/sec > 1.07 cm/sec) anions during the daytime period. And the average dry deposition order and velocity for downward ionic species were NO3(-) > Cl- > K+ > Ca2+ (2.92 cm/sec > 2.74 cm/sec > 0.96 cm/sec > 0.93 cm/sec) anions during the night-time period. The average dry deposition order and velocity for upward ionic species were Cl- > Ca2+ > K+ > Mg2+ (4.69 cm/sec > 0.62 cm/sec > 0.59 cm/sec > 0.55 cm/sec) anions during the daytime period. And the average dry deposition order and velocity for upward ionic species were Cl- > Ca2+ > Mg2+ > K+ (1.65 cm/sec > 0.43 cm/sec > 0.37 cm/sec > 0.33 cm/sec) anions during the night-time period. The results also indicated that the sodium and chloride concentrations in total suspended particulate were highly positively related, indicating that the sea-salt aerosols were the major contributors for these species at this sampling site of central Taiwan.

Chromatography, Ion Exchange↗