Guor-Cheng Fang

Characterization of particulate, metallic elements of TSP, PM2.5 and PM2.5-10 aerosols at a farm sampling site in Taiwan, Taichung

Atmospheric aerosol particles and metallic concentrations were monitored at the Experimental Farm of Tunghai University (EFTU) sampling site in this study. Total suspended particulate matter (TSP) was collected by using a PS-1 sampler at the farm-sampling site, in central Taiwan, from July 2001 to April 2002. At the same time, PM(2.5) and PM(2.5-10) were also measured with a Universal sampler from January 2002 to April 2002. Only subjects with the most complete data records on TSP sampling (N=43) and PM(10) sampling (N=23) were used in this analysis. Taichung Industrial Park, Taichung Kang Road (traffic) and a Hospital Incinerator surround the Experimental Farm of Tunghai University. Atmospheric concentrations of metallic elements were analyzed by a flame atomic absorption spectrophotometer (AA-680/G). The results indicated that the metallic elements Mg, Cu and Mn were the largest components in the TSP fraction; the metallic elements Fe and Cd were the largest composition in the PM(2.5-10) fraction; however, the metallic elements Pb, Zn, Cr and Ni were the largest abundance in the PM(2.5) fraction. The atmospheric metallic elements in the TSP, PM(2.5) and PM(2.5-10) fractions came different emission sources, such as soil, traffic, industry and resuspended particles.

Ambient suspended particulate matters and related chemical species study in central Taiwan, Taichung during 1998–2001

Abstract Ambient suspended particulate (PM 2.5 , PM 2.5–10 , TSP) was collected from June 1998 to February 2001 in Taichung, central Taiwan. In addition, the related water-soluble ionic species (Cl − , NO 3 − , SO 4 2− , Na + , NH 4 + , K + , Mg 2+ , Ca 2+ ) and metallic species (Fe, Zn, Pb, Ni) were also analyzed in this study. The results showed that the concentrations of particulate mass are higher in the traffic site (CCRT) than the other sampling sites in this study. Also, the fine particle (PM 2.5 ) concentration is the dominant species of the total suspended particles in Taichung, central Taiwan. The dominant species for PM 2.5 are sulfate and ammonium at all sampling sites during the period of 1998–2001. The results of diurnal variation at THUC sampling site are also discussed in this study. Overall, acidic and secondary aerosol (Cl − , NO 3 − , SO 4 2− and NH 4 + ) is a more serious air pollutant issue in southern and central Taiwan than at several sites around the world. Therefore, ambient suspended particulate monitoring in Taichung, central Taiwan will be continuing in our following study to provide more information for the government to formulate environmental strategy.

Characterization of chemical species in PM2.5 and PM10 aerosols in suburban and rural sites of central Taiwan.

Aerosol samples for PM2.5 (particulate matter with aerodynamic diameters less than 2.5 microns), PM2.5-10 (particulate matter with aerodynamic diameters between 2.5 and 10 microns) and TSP were collected from June to September 1998 at THU (suburban) and HKIT (rural) sites in central Taiwan. The ratios of PM2.5/PM10 averaged 0.70 for the daytime and 0.63 for the nighttime at THU, respectively. At HKIT, the PM2.5/PM10 ratios averaged 0.56 for the daytime and 0.72 in the nighttime, respectively. These results indicated that the PM2.5 concentrations contribute the majority of the PM10 concentration and PM10 concentrations contribute the majority of the TSP at both sites. The averaged PM2.5 concentrations at THU are higher than those measured at HKIT during the daytime period. However, the average PM2.5-10 concentrations in THU are lower than those measured at HKIT during nighttime. The samples collected were also analyzed by atomic absorption spectrophotometry for the elemental analysis of Ca, Fe, Pb, Zn, Cu, Mn and Cr. Meanwhile ion chromatography was used to analyze for the water-soluble ions: sulphate, nitrate and chloride in the Universal samples. The concentrations of heavy metals in PM10 during daytime were all higher than nighttime at THU. However, the averaged concentrations of metal elements in PM10 during day and night period were distributed irregularly at HKIT. The results indicated that for metal elements collected at HKIT have different emission sources. The concentrations of metal elements during daytime in PM10 at THU were generally higher than HKIT. The phenomena owing to the averaged PM2.5 particle concentrations at THU (suburban) were higher than those measured at HKIT (rural) and PM2.5 occupied the major portions of PM10 for both sites during the day period. For anion species, there are no significant differences between day and night period in PM10 concentrations at both suburban and rural sites.

The study of fine and coarse particles, and metallic elements for the daytime and night-time in a suburban area of central Taiwan, Taichung

Daily average concentrations of fine and coarse particulates, and TSP samples have been measured simultaneously at daytime and night-time periods by using Universal and PS-1 sampler in a suburban area of central Taiwan from June to August 1998. The samples were analyzed by atomic absorption spectrometry to determine the fine and coarse particulate concentrations of metallic elements (Ca, Fe, Mn, Pb, Cu, Zn and Cr). The concentration of PM2.5 and TSP showed a decreased trend for the daytime period. The fine particle concentrations were about two times as that of coarse particulate concentrations. The averaged fine particulate concentrations at daytime are higher than at night-time. Ca and Fe were mostly in the coarse particulate mode. The correlation coefficients were 0.63 and 0.69 for elements Ca and Fe in the coarse particle mode for day and night periods. Pb showed a similar distribution ratio with Mn for the fine to coarse particle ratios at both day and night period. Pb and Mn are highly correlated for the day (R = 0.78) and night period (R = 0.61) at particle size <2.5 microm. Cu and Zn were mainly in fine particles at both day and night period. Fe and Ca consist of the major parts of all the elements. Elemental Mn is the lowest among the rest of the heavy metals.

Polycyclic aromatic hydrocarbons in the ambient air of suburban and industrial regions of central Taiwan

The concentrations of gas-phase and particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously at an industrial area (Taichung Industrial Park) and a suburban area (Tunghai University Campus) in Taichung, Taiwan. Twenty-four hours samplings for two consecutive days were performed between August and December 2002 at both sampling sites. Ambient air particle-bound PAHs were collected on quartz filters and gas-phase PAHs were collected on glass cartridges using a PUF Sampler, respectively. Both types of samples were extracted with a DCM/n-hexane mixture (50/50, v/v) for 24 h, then the extracts were subjected to gas chromatography-mass spectrometric (GC-MS) analysis. Total PAHs concentrations at the Taichung Industrial Park (TIP) sampling site and the Tunghai University Campus (THUC) sampling site were found to be 1232.3+/-963.6 and 609.8+/-356.3 ng/m(3), respectively. Stationary combustion processes were mainly responsible for PAHs sources at the TIP sampling site, while traffic vehicle exhaust was the largest contributor for PAHs sources at the THUC sampling site.

Study of atmospheric metallic elements pollution in Asia during 2000–2007

The main purpose of this study is to observe the concentration variations for metallic elements in the atmosphere in Asian countries during 2000-2007. These metallic elements typically generated by human activities are directly or indirectly detrimental to human health. The results show that the highest average metallic elements concentrations of Fe, Cu, Zn and Mn in total suspended particles (TSP) were in China, while the lowest average concentrations were in Japan. For metallic elements Cr and Ni, the highest average concentrations in Japan. The highest average concentrations for metallic element Pb were in China while the lowest average concentrations were in Hong-Kong. These analytical results show that the highest average metallic elements concentrations of Pb, Mn, Cr and Ni in PM(10) occurred in Hong-Kong while the lowest average concentrations were in India. In addition, the lowest average concentrations for Zn and Fe occurred in India. These analytical results demonstrate that the highest average concentrations of Pb in PM(2.5) occurred in Hong-Kong while the lowest average concentration was in Japan. The lowest average concentrations for Cu, Mn, Cr and Ni, the average lowest concentrations occurred in Bangladesh. Taiwan had the lowest average concentrations of Cu and Ni among all Asian countries studied during 2000-2007.

Monitoring and modeling of PCB dry deposition in urban area

Abstract Dry deposition and air sampling were undertaken simultaneously in the ambient air of an urban site by using several dry deposition plates, two MOUDIs (micro-orifice uniform deposited impactors), one NRI (Noll rotary impactor) and several PS-1 (General Metal Work, PS-1) samplers from January to May 1994 in Tainan City, Taiwan. The dry deposition plate, which had a smooth surface, was always pointed into the wind. The PCB (polychlorinated biphenyl) congeners were analyzed primarily by using a gas chromatograph with a 63Ni electron capture detector (ECD). The measured dry deposition flux of total PCBs varied between 3.48 and 6.79 μg m−2 per day and averaged ≈ 4.73 μg m−2 per day. This was up to three orders of magnitude higher than the fluxes measured at the Great Lake and remote areas and close to those measured at urban areas by previous studies. The particle-bound PCB homologue composition collected by the dry deposition plate varied between 0.76 μg g−1 (di-CBs) and 11.5 μg g−1 (hexa-CBs). This profile of PCB homologues is similar to the pattern of Aroclor 1260 which is dominant in hexa-CBs and hepta-CBs. Because of their higher vapor pressure, in general, the less-chlorinated PCB homologues have a greater PCB mass fraction in the gas phase. The mean dry deposition velocities of PCB homologues ranged between 0.09 and 0.58 cm s−1. In general, the more highly chlorinated PCB homologues have a higher dry deposition velocity. Particle size distributions ( d C d(log D p ) vs. Dp) of total PCBs were found to be bimodal. The highest peak was localized in the particle size range between 5.6 and 10.0 μm and the second peak was localized in the particle size range between 0.31 and 0.52 μm. The particle MMD0 of total PCBs was 1.68 μm and more than 85% of the PCB mass was found in the particles smaller than 10 μm. By using the particle size distribution data, the dry deposition model used in this study can provide a good prediction for the dry deposition flux of total particle mass, total PCBs and PCB homologues. For both total particle mass and total PCBs, more than 87.5% of the dry deposition flux is contributed by particles of size > 10 μm. This is because particles larger than 10 μm have a higher dry deposition velocity (> 2.60 cm s−1) and, therefore, control the majority of the dry deposition flux.

Characterization of atmospheric PM10 and related chemical species in southern Taiwan during the episode days

The concentrations of atmospheric PM10 on days with episodes of pollution were examined at four different sampling sites (CC, DL, LY, and HK) in southern Taiwan. The related to particulates water-soluble ionic species (Na+, K+, Mg2+, Ca2+, NH4+, Cl-, NO3-, SO4(2-)), carbonaceous species (EC and OC) and metallic species (Zn, Ni, Pb, Fe, Mn, Al, Si, V) were also analyzed. On the episode days of this study, the PM10 mass concentration ranged from 155 to 210 microgm(-3), from 150 to 208 microgm(-3), from 182 to 249 microgm(-3), and from 166 to 228 microgm(-3) at CC, DL, LY, and HK, respectively. The results indicate that the dominant water-soluble species were SO4(2-), NO3-, NH4+, and Cl- at the four sampling sites on these days. Moreover, the high sulfate and nitrate conversion values (SOR and NOR) presented herein suggest that secondary formations from SO2 to SO4(2-) and from NO2 to NO3- are present in significant quantities in the atmosphere of southern Taiwan on episode days. In particular, high SOR and NOR verified that both SO4(2-) and NO3- dominated the increase of atmospheric PM10 concentration in southern Taiwan on episode days.

Concentration of atmospheric particulates during a dust storm period in central Taiwan, Taichung.

In this study we monitored concentrations of particles in central Taiwan using PS-1 (GPS1 PUF Sampler) and Model 310 Universal Air Sampler (UAS) from 02/23/2001 to 03/12/2001 at two sampling sites. During this period, an Asian dust storm moved across central Taiwan from 3/3 to 3/6. The total ambient air particle concentrations during the dust storm period were than compared with previous data from this region. In general, the average total suspended particulate (TSP) concentration order was during dust storm period > after dust storm period > non-dust storm period at both HKITT (traffic) and THUC (rural) sampling sites. The ratio of PM2.5/PM10 was 60% before and after the dust storm period. However, this ratio was decreased to less than 50% during the dust storm. This demonstrates that the coarse particulate concentrations (PM2.5-10) increased during the dust storm period. In contrast the increase of ambient air particles concentrations after the Taiwan Chi-Chi Earthquake were mainly due to fine particles (PM2.5). And, the increased of ambient air particles concentrations after dust storm period were mainly coarse particle (PM2.5-10) concentrations in central Taiwan.

Predicting the exceedances of a critical PM10 concentration—a case study in Taiwan

Abstract Three theoretical distributions, lognormal, Weibull and type V Pearson, were used to fit the parent distribution of the PM10 at five air monitoring stations in Taiwan from 1995 to 1999. However, these distributions cause large errors in predicting air pollutant concentration in the high-concentration region. Two prediction methods, method I: type I asymptotic distribution of extreme value and method II: type I two-parameter exponential distribution, were used to fit the distributions of the monthly maximum and high PM10 concentration over a specific percentile, respectively. Moreover, these two methods were taken to estimate the return period and exceedances of a critical PM10 concentration, such as Taiwan EPAs standard, in Taiwan. The result indicates that the lognormal distribution is the most appropriate parent distribution to represent whole PM10 data. However, the fitted type I two-parameter exponential distribution is better matched with the high PM10 concentration levels than the parent lognormal distribution. Both of the prediction methods (I and II) can successfully estimate the return period and exceedances over a critical concentration during the sampling period.