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This study collected ambient air total suspended particle (TSP) concentrations and dry depositions at Taichung Science Park sampling site. The metallic elements concentrations and dry depositions were analyzed. The possible pollutant sources are discussed in this study. In addition, this study used the principal component analysis method to find metallic element sources and their transportation pathway and distributions at Taichung Science Park (T.S.P). The results indicated that the average highest TSP concentrations and dry deposition fluxes occurred in the autumn and winter seasons. The highest average metallic element concentration and dry deposition was Fe, while the lowest average metallic element concentration and dry deposition was Hg(p). The study results further indicated that the lowest metallic element concentrations and dry depositions all occurred in the summer season. The pollutant parcels originated from the northern Taiwan counties and sea surface in the autumn, winter and spring seasons. Factor 1 was responsible for the local industrial emission results and traffic road dust. The metallic elements Hg(p) yield a value greater than 0.7 in Factor 2 which revealed that ambient air particulate pollutants were generated from Taichung Thermal Power Plant (T.T.P.P.) emissions and were transported from the coastal area of mainland China cities. The mean seasonal concentration differences existed for ambient air particulates, and there were no mean seasonal concentrations differences for all metallic elements. In addition, there were no significant mean concentrations differences for all metallic elements and meteorological factors such as temperature, humidity and wind speed. Therefore, the ambient air metallic element emissions were stable and considered primary emissions sources. The health risk value for metallic element Cr was higher than that for the acceptable health risk value suggested by the EPA. Metallic element Cr revealed that it was no mean seasonal concentrations differences. Thus, metallic element Cr was considered came from local emission source at this T.S.P. sampling site. [ABSTRACT FROM AUTHOR]

In this study, the concentrations and dry deposition of ambient air particulates are measured using a PS-1 sampler and a dry deposition plate at a suburban sampling site in central Taiwan from January 2019 to August 2019. The concentrations of metallic elements that are attached to the particulates and dry deposits are analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The source analysis model was used to identify possible emission sources of the pollutants and the transmission distributions of ambient air metallic elements. During the sampling period, the TSP concentration at the Peiying suburban sampling site was highest on January 24th (in winter) and lowest on April 29th (in spring). Dry deposition was greatest on January 9th (in winter) and least on July 29th (in summer). In addition, the correlation coefficient between temperature and ambient air particulate concentration revealed a moderate to strong negative relationship (r2 = 0.60) the ambient air particulate concentrations declined throughout the study period. Moreover, high concentrations of crustal metallic elements Al, Ca were found in this study due to the particulates suspensions from the roads in the suburban area. The Taiwan II express highway runs about 500 m to the northeast of the sampling site, explaining why high concentrations of Cu were measured in this study. The concentrations of metallic elements Ca, Cd, Ni, Pb, and Zn were highest in winter and spring while those of metallic elements Al, Cu, Cr, and Mn were highest in summer. The mean metallic elemental concentrations followed the order: Ca > Al > Zn > Cu > Mn > Ni > Pb > Cr > Cd. The dry depositions of metallic elements Ca, Pb, Zn, Ni and Cd were greatest in winter and spring and those of metallic elements Al, Cu, Cr and Mn were highest in summer. The average dry depositions of the studied metallic elements followed the order: Ca > Al > Zn > Cu > Mn > Ni > Pb > Cr > Cd. The main pollution parcel was from the north side of Taiwan, pollution parcel that associated with the northeast monsoon, resulted in ambient air pollutants emitted on Taiwan island, influencing its air quality. [ABSTRACT FROM AUTHOR]

Ambient air particulates (PM1, PM2,5, PM10, PM18, and total suspended particulates (TSP)), trace metals (Al, As, Cr, Cu, Cd, Zn, Ni, Pb, Mn, and Hg(p)) their concentrations, their dry deposition, and their sources from Dec. 2017 to May 2018 at Luliao Taichung City Junior High School (24°14′37.9″N 120°34′00.3″E) were studied. The site is a mixed site that is surrounded by traffic, and urban and commercial activities. The sources of ambient air particulates were identified by back-trajectories analysis. The trace metal concentrations in PM1, PM2.5, and PM10 were compared with those in other countries in the years 2003–2018. The level of contamination by these trace metals at this mixed site was evaluated using a contamination factor (CF) and degree of contamination (CD). The results indicated that the average concentrations of all particles were highest in January (winter season) and the average concentrations of TSP, PM18, PM10, PM2.5, and PM1 followed the order Jan. 2018 > Dec. 2017 > Apr. 2018 > Mar. 2018. The concentration of trace metals followed the order Al > Cu > Fe > Cr > Mn > Ni > As > Pb > Zn > Cd > Hg(p) in both TSP and dry deposits. Al had the highest mean concentration in PM18, PM10, PM2.5, and PM1 while Hg(p) had the lowest concentration in PM18, PM10, PM2.5, and PM1. Interestingly, elements As and Cr had higher mean concentrations in PM1 at the studied site than in the other countries of interest during the years from 2003 to 2018. CF and CD values for all trace metals revealed low degree of contamination at this mixed sampling site. The CD values for all trace metals in particle of sizes 1 to 18 μm all exceeded those calculated for TSP and dry deposits. The CD values increased with particle size from 1 μm to 18 μm. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to monitor ambient air particles and particulate-bound mercury Hg(p) in total suspended particulate (TSP) concentrations and dry deposition at the Hung Kuang (Traffic), Taichung airport and Westing Park sampling sites during the daytime and nighttime, from 2011 to 2012. In addition, the calculated/measured dry deposition flux ratios of ambient air particles and particulate-bound mercury Hg(p) were also studied with Baklanov & Sorensen and the Williams models. For a particle size of 10 μm, the Baklanov & Sorensen model yielded better predictions of dry deposition of ambient air particulates and particulate-bound mercury Hg(p) at the Hung Kuang (Traffic), Taichung airport and Westing Park sampling site during the daytime and nighttime sampling periods. However, for particulates with sizes 20-23 μm, the results obtained in the study reveal that the Williams model provided better prediction results for ambient air particulates and particulate-bound mercury Hg(p) at all sampling sites in this study. [ABSTRACT FROM AUTHOR]

This investigation measures the concentrations of arsenic (As), (As), (As) in total suspended particles (TSP) and dry deposits at five characteristic sampling sites in central Taiwan during the years 2009-2010, and identifies their seasonal variations. The investigation was performed in region in which a science park, transportation, waste incineration facility, fossil fuel combusting steel factory, electronics factory, plastic factory, chemical factory and Taichung Thermal Power Plant (TTPP) are located. The Bei-shi sampling station and He-mei town sampling station were located in, an area of heavy transportation. The Quan-xing sampling station was close to an electronics factory and a fossil fuel combusting steel factory. The As for Chang-Hua sampling station was located at the chemical factory. Finally, the Gao-Mei wetland sampling station was close to a waste incineration; they were characterized as a waste incineration plant and TTPP. The highest average concentrations of arsenic in TSP were found at Quan-xing (industrial) and the lowest were found at He-mei (residential). The average amounts of dry deposited arsenic (As), (As) and (As) were highest at the Quan-xing (industrial) site and lowest at the Gao-mei (wetland) site. The average seasonal concentrations of (As), (As) and (As) in TSP and the average dry deposited amounts were highest in the autumn and lowest in the summer at five sampling sites. [ABSTRACT FROM AUTHOR]

Field mobile monitoring of PM 2.5 , equipped with a highly accurate device, was performed for two types of urban parks in Taiwan. Measurements were taken in the morning and evening rush hours, on certain weekdays and weekends, every month over a year. We designed six calculation schemes of the rate of PM 2.5 mitigation by urban parks to comprehensively compare the average and maximum mitigation effects in relation to the vegetation barriers. The mitigation rate, from the lowest (2.51%) to the highest (35.57%) depended on the calculation schemes. The Taipei Botanical Garden (TBG) with a dense, multilevel forest has a stable PM 2.5 mitigation effect and strong ability to improve air quality inside the park under severe PM 2.5 pollution. In contrast, Zhonghe No.4 Park (ZHP), an open park with mostly a single-storied stand, has variable PM 2.5 mitigation effect, leading to either quick dissipation or accumulation of PM 2.5 inside the park. Furthermore, the dry deposition of PM and the associated heavy metals were investigated using camphor trees as bioaccumulators. Dry deposition flux of the leaf-deposited PM 2.5 exhibited similar results in ZHP; whereas, noticeable higher results were observed inside TBG. In addition, most of the PM 2.5 deposition flux from field estimations were similar to those in i-Tree Eco when considering the loss of mass due to the dissolution through water filtration, indicating that i-Tree Eco may be reliable to model the removal of PM 2.5 in the parks in Taiwan. Moreover, we examined nine heavy metals' content in the deposited PM, and most of the detectable elements were significantly higher outside both parks, demonstrating the mitigation effects of urban parks in reducing not only the PM 2.5 concentration but also the toxicity of the pollutant. This study provides direct evidence of the important ecosystem services, namely air quality improvement and biomonitoring effect, derived from urban parks. [Display omitted] • Six calculation schemes of PM 2.5 mitigation rate were performed in the two parks. • Urban parks reduce PM 2.5 from 2.51% (average scheme) to 35.57% (maximum scheme). • Heavy metals inside the parks were twice lower than the external concentrations. • A park with dense vegetation has a stable PM 2.5 mitigation effect. • A reduction of 21% was found in a highly vegetated park under severe PM 2.5 level. [ABSTRACT FROM AUTHOR]

This study monitored ambient air particles and the metallic elements Cu, Cr, Cd, Pb, and Zn in total suspended particulate (TSP) concentrations and dry deposition during the day and nighttime sampling period at a traffic sampling site in central Taiwan from 2012 March to 2013 February. The dry deposition flux ratios and seasonal concentration variations of ambient air particles and these metallic elements are also discussed. The results indicate that for all the elements, except for Zn, the highest average concentrations in TSP occurred in the spring and summer, while the lowest average was in the fall and winter for both day and nighttime sampling periods. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to monitor ambient air particles and metallic elements (Zn, Pb, Mg, and Ca) in total suspended particulates (TSP) concentrations and dry deposition. In addition, the calculated/measured dry depositions flux ratios of ambient air particles and metallic elements (Zn, Pb, Mg, and Ca) were also evaluated using Wood's model at Hung Kuang (traffic) site in Central Taiwan from years 2011 to 2012. The results indicated that: 1) the mean highest concentration for metallic element Zn occurred at 10 μm particle size during the daytime sampling period; 2) the mean highest concentration of metallic elements Mg occurred at 23 μm particle size during the nighttime sampling period; and 3) the mean highest concentration of metallic element Pb occurred at 20 μm particle size for the average sampling time of the daytime and nighttime sampling periods at this traffic sampling site. [ABSTRACT FROM AUTHOR]

Experiments were carried out between September 2009 and August 2010 at Bei-shi and Gao-mei in Taichung, and at Quan-xing, Chang-Hua and He-mei in Changhua. Dry-deposition flux models of metallic elements Mn, Fe, Zn, Cu and Cr bound to air particulates at five characteristic sampling sites were developed. Results concerning metallic elements Mn, Zn, Cr and Cu, revealed that Zhang's model yielded the best results concerning the dry-deposition flux of particles of size 10 μm at Bei-shi, Chang-Hua, He-mei, Quan-xing and Gao-mei sampling sites. For the metallic element Cr, the model of Noll and Fang exhibited the best dry-deposition flux results for particles of size 10 μm at Bei-shi, He-mei and Gao-mei sampling sites. For metallic element Fe, the model of Noll and Fang yielded the best results for the dry-deposition flux of particles of size 5.6 μm at Bei-shi, Chang-Hua, He-mei and Quan-xing sampling sites. For metallic element Fe, Zhang's model yielded the best dry-deposition flux results for particles of size 5.6 μm at the Gao-mei sampling site. For ambient air particles, Zhang's model yielded the best average calculated/modeled ratios for particles of size 3 μm, and the model of Noll and Fang yielded the best average calculated/modeled for particles of size 10 μm. Finally, the models of both Zhang and Noll and Fang yielded more accurate predictions of the dry-deposition of metallic elements in ambient air when the particles were larger than 5.6 μm. [ABSTRACT FROM AUTHOR]

From September 2011 to February 2012, ambient air particulate and particulate-bound mercury [Hg(p)] concentrations were measured, together with dry deposition using a cold vapor atomic fluorescence spectrometry (CVAFS) analyser, at two characteristic sampling sites in central Taiwan. Results from the sampling site at Westin Park indicated that the lowest particulate dry deposition and lowest average particulate concentrations in total suspended particles (TSP) occurred in September (29.70±7.47 μ g m−2×min) and February (34.38±13.60 ng m−3), respectively. Moreover, results from the Gung-Ming junior high school (airport) site, showed that the highest average particulate dry deposition and average highest particulate concentrations in TSP occurred in February (156.76±30.36 μ g m−2×min) and January (125.49±9.51 ng m−3), respectively, during the winter. The Dragon Steel Plant and Han-Shian Aerospace Industrial Development Corporation were both nearby. These factors led to the high Hg(p) concentrations at Taichung Airport (TA) compared with Westin Park. Local large suspended particulates from heavy traffic were the main reason for the high average Hg(p) deposition at Westin Park compared with TA in this study. [ABSTRACT FROM PUBLISHER]

This study focuses on particulate-bound Hg (Hg[p]) composition (ng/g) (defined as ng/g), concentrations (ng/m3) and dry deposition (ng/m2*min) variations for PM18, PM10, PM2.5, and PM1.0. Three characteristic sampling sites collected 1-day ambient suspended particles during November and December 2010 using MOUDI-100S4 samplers. Additionally, Hg(p) size distributions are also characterized. Composition variations of Hg(p) in PM18 were in the order of 0.158 ± 0.055 ng/g (Quan-xing sampling site) > 0.086 ± 0.097 ng/g (Hung-kuang sampling site) > 0.083 ± 0.065 ng/g (Gao-mei sampling site). Further, composition variations of Hg(p) in PM10 were in the order of 0.115 ± 0.038 ng/g (Quan-xing site) > 0.107 ± 0.080 ng/g (Gao-mei site) > 0.103 ± 0.060 ng/g (Hung-kuang site). Composition variations of Hg(p) in PM2.5 were in the order of 0.885 ± 0.423 ng/g (Quan-xing site) > 0.458 ± 0.105 ng/g (Gao-mei site) > 0.372 ± 0.157 ng/g (Hung-kuang site). Finally, composition variations of Hg(p) in PM1.0 were in the order of 0.913 ± 0.441 ng/g (Quan-xing site) > 0.698 ± 0.293 ng/g (Hung-kuang site) > 0.508 ± 0.270 ng/g (Gao-mei site). The Hg(p) size distribution peaked at 1.0 μm at the Quan-xin site, and the lowest average Hg(p) size distribution was 18 μm at the Hung-kung site. The main possible sources for atmospheric particulate-bound mercury Hg(p) were likely from transportation, chemical plant and fossil fuel combustion (Fang et al., 2011). In addition to the above findings, other possible nearby sources at Taichung Thermal Power Plant (TTPP) and Central Taiwan Science Park (CTSP) were: steel industry, electronic industry, plastic industry, chemical industry, basic metal manufacturing, machinery manufacturing, coal products and petroleum. Our sampling sites were in the regions of all of the above sources. [ABSTRACT FROM AUTHOR]

Ambient air particulate-bound Hg (Hg[p]) concentrations, dry deposition and dry deposition velocity were measured using a cold vapor atomic fluorescence spectrometry (CVAFS) analyzer in the spring season (between March 2011 to June 2011) at the Westin Park sampling site, in Sha-Lu central Taiwan. The results indicated that the highest ambient air Hg(p) concentrations total suspended particles (TSP) occurred in April (0.050 ng/m3) while the lowest ambient air Hg(p) concentrations in TSP occurred in March (0.011 ng/m3). Moreover, the results showed that the highest Hg(p) dry deposition occurred in June (0.019 ng/m2*min), while the lowest ambient air Hg(p) dry deposition occurred in March (0.002 ng/m2*min). In addition, the results also showed that the highest and lowest dry deposition velocity for ambient air Hg(p) occurred in June (2.46 cm/sec) and May (0.18 cm/sec), respectively. Finally, the average highest and lowest dry deposition velocity for ambient air particulates occurred in March (9.010 cm/sec) and April (2.09 cm/sec), respectively. [ABSTRACT FROM AUTHOR]

Abstract: Total gaseous mercury (Hg) (TGM), gaseous oxidized Hg (GOM), and particulate-bound Hg (PBM) concentrations and dry depositions were measured at an urban site in central Taiwan. The concentrations were 6.14±3.91ngm−3, 332±153, and 71.1±46.1pgm−3, respectively. These results demonstrate high Hg pollution at the ground level in Taiwan. A back trajectory plot shows the sources of the high TGM concentration were in the low atmosphere (<500m) and approximately 50% of the air masses coming from upper troposphere (>500m) were associated with low TGM concentrations. This finding implies that Hg is trapped in the low atmosphere and comes from local Hg emission sources. The conditional probability function (CPF) reveals that the plumes of high TGM concentrations come from the south and northwest of the site. The plume from the south comes from two municipal solid waste incinerators (MSWIs). However, no significant Hg point source is located to the northwest of the site; therefore, the plumes from the northwest are hypothesized to be related to the combustion of agricultural waste. Dry deposition fluxes of Hg measured at this site considerably exceeded those measured in North America. Overall, this area is regarded as a highly Hg contaminated area because of local Hg emission sources. [Copyright &y& Elsevier]

Abstract: This investigates the concentrations of Mn, Zn, Cr, Cu, and Pb ambient air in total suspended particulates (TSPs) and dry deposition. The ratios of the calculated to measured dry deposition fluxes of ambient-air Mn, Zn, Cr, Cu and Pb at five characteristic sampling sites from 2009 to 2010 were determined using two dry deposition models. Experimental results demonstrate that the mean concentrations of metallic elements in TSPs and dry deposition were highest at the Quan-xing (industrial) sampling site, which is surrounded by various industrial factories and is in a severely polluted area. The mean seasonal concentrations of metallic elements in TSPs were highest in the winter and fall at all five sites. The analytical concentrations of metallic elements in fall and winter at these five sites were elevated in low winds. The Baklanov model yielded more accurate predictions concerning the dry deposition of metallic elements in ambient air when the sizes of the deposited particles were <5.6μm, and the Noll and Fang model yielded better predictions when the sizes of the particles were >5.6μm. [Copyright &y& Elsevier]

Abstract: This investigation monitors the concentrations of ambient air arsenic species (As, As(III) and As(V)) in total suspended particulates (TSPs) and dry deposits. Calculated/measured dry deposition flux ratios of ambient air arsenic species at five characteristic sampling sites in the years 2009–2010 are determined using two dry deposition models. An analysis reveals that the average concentrations of arsenic species in TSPs and dry deposits were highest at the Quan-xing sampling site, located in a severely polluted area where numerous industrial factories are located. The average seasonal concentrations of arsenic species in TSPs were highest in winter and fall in all instances. Analytical results reveal that low-wind conditions increased the concentrations of arsenic species in fall and winter at the five study sampling sites. Finally, Noll and Fang''s model yielded the best predictions of the dry-deposited ambient air arsenic species (As, As(III), and As(V)) dry deposition for when the particles were larger than 5.6μm, while Baklanov and Sorensen''s model yielded the most accurate results when the particles were smaller than 5.6μm. [Copyright &y& Elsevier]

The main purpose for this study is to observe the seasonal and monthly variations for arsenic (As) in total suspended particulates (TSP) concentration and dry deposition at five characteristic sampling sites during the years 2009 and 2010 in central Taiwan. The results show that the highest and lowest monthly average As concentrations in TSP occurred in January and May at Bei-shi (suburban/coastal) and Quan-xing (industrial) sampling sites. In addition, the results show that the highest and lowest monthly average As dry deposition occurred in October and May at Chang-hua (downtown) and Gao-mei (wetland) sampling sites. This study reflected that the mean highest As concentrations in TSP and mean highest As dry deposition occurred at Quan-xing (industrial). However, the mean lowest As concentrations in TSP and mean lowest As dry deposition also occurred at Gao-mei (wetland). Regarding seasonal variation, the results show that the As average seasonal concentration order in TSP was winter > spring > fall > summer, respectively, at Chang-hua (downtown) and He-mei (residential) sampling sites. Finally, the order of As average seasonal dry deposition was fall > winter > spring > summer, respectively, at Chang-hua (downtown), He-mei (residential), and Gao-mei (wetland) sampling sites. [ABSTRACT FROM AUTHOR]

The main purpose for this study is to observe the seasonal and month variations for particulates-bound mercury Hg(p) in total suspended particulates (TSP) concentration, dry deposition at five characteristic sampling sites during years of 2009-2010 in central Taiwan. The results show that the highest and lowest monthly average particulates-bound mercury Hg(p) concentrations in TSP were occurred in Dec. and Oct. at Gao-mei (wetland), Chang-hua (downtown) and He-mei (residential) sampling site. In addition, the results show that the highest and lowest monthly average particulates-bound mercury Hg(p) dry deposition was occurred in Feb. and Oct. at Quan-xing (industrial) sampling site. This study reflected that the mean highest particulates-bound mercury Hg(p) concentrations in TSP and mean highest particulates-bound mercury Hg(p) dry deposition were occurred at Gao-mei (wetland) and Quan-xing (industrial). However, the mean lowest particulates-bound mercury Hg(p) concentrations in TSP and mean lowest particulates-bound mercury Hg(p) dry deposition were also occurred at Gao-mei (wetland). Regarding seasonal variation, the order of mean-particulates-bound mercury Hg(p) concentrations in TSP in winter and spring were Gao-mei (wetland) > Quan-xing (industrial) > Bei-shi (suburban/coastal) > Chang-hua (downtown) > He-mei (residential). Finally, the order of mean-particulates-bound mercury Hg(p) dry deposition in fall, spring and summer were Quan-xing (industrial) > Bei-shi (suburban/coastal) > Chang-hua (downtown) > He-mei (residential) > Gao-mei (wetland). [ABSTRACT FROM AUTHOR]

The focus of this study is to observe the seasonal variations of particulate bound mercury Hg(p) concentration and amount of Hg(p) (ng/g) in total suspended particulates (TSP) and dry deposition at two (industrial and wetland) characteristic sampling sites in Taiwan, during the years 2009-2010. Concentrations of Hg(p) from each sample (quartz filter, overhead projection film) were analyzed by a direct Hg(p) analyzer DMA-80. Approximately 30 mg of the filter sample was loaded directly into the DMA-80 and analyzed. The results indicated that the mean highest Hg(p) in TSP (expressed in ng/m3) and dry deposition (expressed in ng/m2/min) both occurred at the industrial site (Quan-xing) while the corresponding mean lowest Hg(p) concentrations occurred at the wetland site (Gao-mei). Also, the mean highest amount of Hg(p) (expressed in ng/g) in TSP and dry deposition occurred at the industrial site (Quan-xing), while the mean lowest amount of Hg(p) occurred at the wetland site (Gao-mei). Metal products manufacturing and heavily loaded traffic during weekdays were possible sources responsible for the high concentrations of Hg(p) observed at Quan-xing (industrial) sampling site. [ABSTRACT FROM AUTHOR]

This study investigated the ambient air particle-bound As(p) and Hg(p) levels and compositions in dry deposition and total suspended particulates (TSP) at five sampling sites in Central Taiwan (suburban/coastal, downtown, residential, industrial and wetland) during the years of 2009 and 2010. The main industrial sources of studied metals in various investigated sites include: steel, electronic, plastic, and chemical industries, the Taichung thermal power plant (TTPP), fossil fuel combustion, a science park, transportation, and waste incineration. The samples were digested with hydrochloric acid (HCl) and nitric acid (HNO3), then they were analyzed for metals by ICP-MS. The mean As(p) levels in dry deposition were the highest at Quan-xing site (industrial) and the lowest at Chang-hua site (downtown). Moreover, the mean Hg(p) levels in dry deposition were the highest at Gao-mei site (wetland) and the lowest at He-mei site (residential). In addition, the mean As(p) levels in TSP were the highest at He-mei site (residential) and the lowest at Gao-mei site (wetland). The mean Hg(p) levels in TSP were the highest at Quan-xing site (industrial) and the lowest at Gao-mei site (wetland). Regarding seasonal variation, the lowest levels in dry deposition for both particles As(p) and Hg(p) occurred in spring and summer. Finally, the lowest levels of As(p) and Hg(p) in TSP were observed in fall and winter. [ABSTRACT FROM AUTHOR]

The main purpose of this investigation was to monitor ambient air particles and metallic elements (Cr, Cu and Pb) in total suspended particulates (TSP) concentration, dry deposition. Furthermore, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements (Cr, Cu and Pb) were evaluated using three dry deposition models at five characteristic sampling sites for the 2009-2010. The results show that the average concentrations of metallic elements Cr, Cu and Pb in TSP were highest at Bei-shi (suburban/coastal) and the lowest at Gao-mei (wetland) among the five characteristic sampling sites during the years 2009-2010. This study also shows that the mean rates of dry deposition of metallic elements Cr and Cu were highest at Quan-xing (industrial) and lowest at Bei-shi (suburban/coastal) and Chang-hua (downtown). Finally, the Noll and Fang model was found to yield better predictions of the dry deposition of ambient air particles and metallic elements Cr and Cu than any of the other deposition models. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to observe the seasonal variations of total suspended particulates (TSP) concentration, dry deposition (and the metallic elements that attach to them) at five characteristic sampling sites in Taiwan during the years of 2009 and 2010. The highest average concentration in TSP for metallic elements Mn and Fe occurred in Quan-xing (industrial area), while the highest average concentration in TSP for metallic elements Cr, Cu, and Pb was observed in Bei-shi (suburban/coastal area). The lowest average concentrations for metallic elements in TSP occurred in Gao-mei (wetland area). In addition, the highest average dry deposition for metallic elements Mn, Fe, and Zn was observed in He-mei (residential area). Also, the highest average dry deposition for metallic elements Cr, Cu, and Pb occurred in Quan-xing (industrial area). The lowest average dry deposition for metallic elements Mn, Fe, and Cr occurred in Bei-shi (suburban/coastal), while the lowest average dry deposition for metallic elements Zn, Cu, and Pb was observed in Chang-hua (downtown). Regarding seasonal variation, the results show that the average seasonal dry deposition order for metallic elements Zn, Cr, and Pb was fall > spring > winter at Bei-shi (suburban/coastal), Chang-hua (downtown), He-mei (residential), and Gao-mei (wetland). Finally, the average seasonal concentration order for Cu in TSP was fall > winter > spring, at Bei-shi (suburban/coastal), He-mei (residential), Quan-xing (industrial), and Gao-mei (wetland) sampling sites. [ABSTRACT FROM AUTHOR]

Abstract: A 60-m flux tower was built on a 2100 m mountain for the measurement of the air pollutant concentration and the evaluation of dry deposition velocity in Central Taiwan. The tower was constructed in an evergreen broadleaf forest, which is the dominant species of forest in the world. Multiple-level SO2 concentrations and meteorological variables at the site were measured from February to April 2008. The results showed that the mean dry deposition velocities of SO2 were 0.61 cm s−1 during daytime and 0.27 cm s−1 during nighttime. From the comparison of the monthly data, a tendency was observed that the dry deposition velocity increases with LAI and solar radiation. Furthermore, it was observed that the deposition velocity was larger over wet canopy than over dry canopy, and that higher deposition velocities in the wet season were mainly caused by non-stomatal uptake of wet canopy. Over wet canopy, the mean dry deposition velocities of SO2 were estimated to be 0.83 cm s−1 during daytime and 0.47 cm s−1 during nighttime; and 0.44 cm s−1 during daytime and 0.19 cm s−1 during nighttime over dry canopy. There is good agreement between the results of this study and those in other studies and the predictions of . The medians (geometric means) of derived r c during daytime are 233 (266) m s−1 over dry canopy and 147 (146) m s−1 over wet canopy. It was found that solar radiation is the critical important meteorological variable determining stomatal resistance during daytime. For non-stomatal resistance, clear dependencies were observed on the friction velocity and relative humidity. [Copyright &y& Elsevier]

This study presents the chemical composition of dry deposition by using dry deposition plate and water surfaces sampler during daytime and nighttime sampling periods at a near highway traffic sampling site. In addition, the characterization for mass and water soluble species of total suspended particulate (TSP), PM2.5 and PM10 were also studied at this sampling site during August 22 to October 31 of 2006 around central Taiwan. The samples collected were analyzed by using Ion Chromatography (DIONEX 100) for the ionic species analysis. Results of the particulate dry deposition fluxes are higher in the water surfaces sampler than that of the dry deposition plate. In other words, the results also indicated that water surface can absorb more ambient dry deposition inorganic pollutants than that of dry deposition plate in this study. The results obtained in this study indicated that the ionic species of Cl−, $$NO^{ - }_{3} $$ and $$SO^{{2 - }}_{4} $$ occupied about average 60~70% downward flux out of total ionic species for either dry deposition plate or water surfaces sampler during August to October of 2006 at this near highway traffic sampling site. [ABSTRACT FROM AUTHOR]

Downward, upward dry deposition fluxes and total suspended particulate of particulate heavy metals (Fe, Pb, Zn, Cu, Mg and Mn) were measured in daytime and nighttime period in Sha-Lu, a small city in the central Taiwan during summer period of 2003. The results showed that the total suspended particulate concentrations of particulate mass in the daytime period (averaged 996.2 g/m3) were higher than in nighttime period (averaged 560.7 g/m3). And the downward dry deposition fluxes (averaged 54.07 g/m2 s) were about two times as that of upward dry deposition fluxes (averaged 26.48 g/m2 s) in the daytime period. Furthermore, the average downward dry deposition fluxes (averaged 26.22 g/m2 s) were also about two times as that of upward dry deposition fluxes (averaged 12.11 g/m2 s) in the nighttime period. In addition, the average downward dry deposition fluxes are greater than the upward dry deposition fluxes for all the heavy metals in either daytime or nighttime period. The proposed reasons are that the wind speed and concentration difference for daytime and nighttime period lead to these results at the traffic sampling site of central Taiwan. In addition, the deposition velocity for mass, heavy metals (Fe, Pb, Zn, Cu, Mg and Mn) during daytime and nighttime period were also calculated. The average daytime dry deposition velocity for downward particulate mass, upward particulate mass, Fe, Pb, Zn, Cu, Mg and Mn were 5.56, 2.66, 1.71, 0.18, 1.06, 0.24, 0.47 and 0.11 (cm/s), respectively. And the average nighttime dry deposition velocity for downward particulate mass, upward particulate mass, Fe, Pb, Zn, Cu, Mg and Mn were 4.70, 2.11, 1.66, 0.18, 0.86, 0.23, 0.32 and 0.07 (cm/s), respectively at traffic sampling site of central Taiwan. [Copyright &y& Elsevier]

Air samples were collected at a highway intersection, coastal location and suburban area in Taichung, Taiwan for the characterization of nitrate containing particulates (NCPs) in dry deposition from October 2002 to February 2003. Sampling was accomplished with a surrogate surface technique in non-raining days. Collecting tapes were precoated with nitron (C20H16N4) in a vacuum evaporator controlled below 10−6 mm Hg. Immediately after collection, samples were placed in a desiccator with a relative humidity of 85% for 2 h to form distinctive products of NCPs. These products were then examined with a scanning electron microscopy. It was found that the average number frequencies of NCPs in total particulate were 41.9%, 35.7%, and 36.8% at the highway intersection, coastal and suburban areas, respectively. Most collected particulates were non-nitrate containing at these sampling sites. The average volume shape factor value of NCPs at the highway intersection was higher than those at the other sampling sites, suggesting that NCPs at the highway intersections were more irregular in shape. Average NCP dry deposition fluxes were 3.9, 2.2 and 2.1 μg m–2 s–1 and non-nitrate containing particulate dry deposition fluxes were 5.4, 3.9 and 3.2 μg m–2 s–1 at the highway intersection, coastal and suburban areas. NCPs <10 μm in size contributed 3.4%, 9.6% and 6.4% by weight to the total dry deposition at the highway intersection, coastal, and suburban areas, respectively, showing that over 90% of dry deposition was particulates larger than 10 μm in diameter. The number median diameters (NMDs) of NCP were 0.47, 0.39 and 0.57 μm and mass median diameters (MMDs) of NCP were 24.2, 26.3 and 24.6 μm at the highway intersection, coastal and suburban sites, respectively. The coastal area had the lowest NMD and highest MMD. The average values of dynamic shape factor (FD) were calculated as 1.21 for fine particles and 1.38 for coarse particles. [Copyright &y& Elsevier]

Sulfate-containing aerosol (SCA) dry deposition at the highway intersection, coastal location, and suburban area in Taiwan were analyzed and compared. Sampling was accomplished with a surrogate surface technique. Samples particles were coated with barium chloride (BaCl2) in a vacuum evaporator and then exposed to a relative humidity of 85% for 2 h to form distinctive products of SCAs. Treated samples were examined by a scanning electron microscopy. SCA dry deposition fluxes were 10.2, 4.1, 3.4 μg m−2 s−1 and nonsulfate-containing aerosol (NSCA) dry deposition fluxes were 23.3, 8.2, 13.5 μg m−2 s−1 at the highway intersection, coastal, and suburban areas. At the highway intersection, both SCA and NSCA dry deposition fluxes were much higher than those at the other two sites. The dry deposition of particles was also analyzed with a traditional technique. The number median diameters (NMDs) of SCA were 0.41, 0.82, and 1.2 μm at the highway intersection, coastal, and suburban sites, respectively. The highway intersection site had a small NMD, which showed that most sulfate-containing deposited aerosols existed in fine diameter range. The mass median diameters (MMDs) of SCA were 8.8, 19.5, and 14.9 μm at the highway intersection, coastal, and suburban sites, which were much higher than NMDs. Average numbers of SCAs in total particulate were 33%, 33%, and 22% at the highway intersection, coastal and suburban areas Most deposited particulates were nonsulfate-containing at the three sampling sites. SCAs less than 10 μm contributed 29%, 8%, and 7% to the total dry deposition at the highway intersection, coastal, and suburban areas, respectively. The contribution of fine particulate was significantly higher at the highway intersection site. [Copyright &y& Elsevier]

Aerosol samples were collected by total suspended particulate (TSP) and dry deposition plate (downward, upward) from August to November in 2003 in central Taiwan. The particulate metallic elements (Fe, Pb, Zn, Cu, Mg and Mn) were also measured in this study during the summer and autumn periods of 2003. The results obtained in this study indicated that the ambient air particulate mass concentrations in the daytime period (averaged 975.4 μg/m3) were higher than the night-time period (averaged 542.1 μg/m3). And the downward dry deposition fluxes (averaged 58.12 μg/m2-sec) were about 2.2 times that of upward dry deposition fluxes (averaged 26.37 μg/m2-sec) in the daytime period. Furthermore, the average downward dry deposition fluxes (averaged 26.54 μg/m2-sec) were also about 2.3 times that of upward dry deposition fluxes (averaged 11.52 μg/m2-sec) in the night-time period. Moreover, the average downward dry deposition fluxes are greater than the upward dry deposition fluxes for all the heavy metals in either daytime or night-time period. In addition, the deposition velocity for mass, metallic elements (Fe, Pb, Zn, Cu, Mg and Mn) during daytime and night-time period were also calculated. In addition, the average TSP composition (mg/g) in the daytime period of the metallic elements (Fe, Pb, Zn, Cu, Mg and Mn) is 1.73, 0.26, 1.16, 0.28, 0.43 and 0.12 mg/g, respectively. And the average TSP composition in the night-time period of the metallic elements (Fe, Pb, Zn, Cu, Mg and Mn) is 3.02, 0.33, 1.57, 0.41, 0.58 and 0.13 mg/g, respectively at traffic sampling site of central Taiwan. [ABSTRACT FROM AUTHOR]

Ambient suspended particulate (dry deposition, TSP) was collected in the traffic sites Sha-Lu, central Taiwan. In addition, the related water-soluble ionic species (CI-, NO3-, SO42-, 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 μg/m²-sec) were about twice that of upward dry deposition fluxes (averaged 26.48 μg/m²-sec) in the daytime period. Furthermore, the average downward dry deposition fluxes (averaged 26.22 μg/m²-sec) were also about twice that of upward dry deposition fluxes (averaged 12.11 μg/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 μg/m³) were higher than in the night-time period (averaged 560.7 μg/m³). The results showed that the total suspended particulate concentrations of particulate mass in the daytime period (averaged 996.2 μg/m³)were higher than in night-time period (averaged 560.7 μg/m³). As for water-soluble ionic species, the average dry deposition order and velocity for downward ionic species were CI- > 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 >2.74cm/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 CI- > Ca2+ > K+ > Mg2+ (4.69 cm/sec >0.62cm/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 CI- > 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. [ABSTRACT FROM AUTHOR]

Atmospheric deposition, either dry or wet, has been identified as an important pathway of mercury (Hg) input to terrestrial and aquatic systems. Although East Asia is the major atmospheric Hg emission source region, very few studies have been conducted to quantify atmospheric Hg deposition in its downwind region. In this study, 8-year (2009-2016) atmospheric Hg dry deposition was reported at the Lulin Atmospheric Background Station (LABS), a high mountain forest site in central Taiwan. Dry deposition of speciated Hg was estimated using a bi-directional air-surface flux exchange model for gaseous elemental mercury (GEM) and dry deposition models for gaseous oxidized mercury (GOM) and particulate-bound mercury (PBM), making use of the monitored speciated atmospheric Hg concentrations. Annual total Hg dry deposition ranged from 51.9 to 84.9 μg m -2 yr -1 , with a multi-year average of 66.1 μg m -2 yr -1 . Among the three forms of atmospheric Hg, GEM was the main contributor to the total dry deposition, contributing about 77.8% to the total, due to the high density of forest canopy as well as the much higher concentration of GEM than GOM and PBM at LABS. Mercury dry deposition is higher in winter and spring than in summer and fall, partly due to the elevated Hg concentrations associated with air masses from East and Southeast Asia where with high atmospheric Hg emissions. The mean annual dry/wet deposition ratio of 2.8 at LABS indicated that Hg deposition to forest landscape was governed by dry rather than wet deposition., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, Cu and Pb) in total suspended particulate (TSP) concentration and dry deposition. In addition, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements (Mn, Fe, Zn, Cr, Cu and Pb) were evaluated using Woods' model at urban and wetland areas for the 2009-2010 period. The results indicated that the mean highest concentrations of metallic elements Mn, Fe, Zn, Cr, Cu and Pb in TSP were found in Chang-Hua (urban) sampling site. And as for the two characteristic sampling sites, the Woods' model exhibits better dry deposition of particulates of 18 µm particle size than the rest of the other particle sizes at any sampling site in this study. The average calculated/measured flux ratios for two seasons (summer and fall) by using Woods model at 2.5, 10 and 18 µm particles sizes were also studied. The results indicated that the average calculated/measured flux ratios orders for two seasons of various particles sizes were all displayed as Fe > Mn > Zn > Cu > Cr > Pb > particle. And these calculated/measured flux ratios orders were Fe > Mn > Cu > Zn > Cr > Pb > particle and were Fe > Mn > Zn > Cu > Cr > particle > Pb, during spring and winter seasons, respectively. Finally, in the spring and summer seasons of Gao-Mei (wetland) sampling site, the average calculated/measured flux ratios using Woods' model was found to be 2.5, 10 and 18 µm, showing the order of the calculated/measured flux ratios to be Fe > Cu > Zn > Mn > Cr > Pb > particle. And the calculated/measured flux ratio orders were Fe > Zn > Mn > Cu > Cr > particle > Pb and were Fe > Cu > Zn > Mn > Cr > particle > Pb for fall and winter season, respectively., (© The Author(s) 2012.)

Dry deposition pollutants were studied in Taiwan and compared with those reported in other areas of the world. The mean dry deposition fluxes in Taiwan were 2.40, 4.98 and 2.47 Mum/m2/sec for Taichung, Tainan and Pingtung, respectively. The correlation coefficients (R2) of mean dry deposition mass flux vs. wind speed were 0.47, 0.90 and 0.69 for Taichung, Tainan and Pingtung, respectively. Dry deposition mass fluxes in Taiwan were the same as in Chicago and about 3 times higher than in the North Sea. Suspended particle concentrations of metal elements (Ca, Fe, Zn, Cu and Cd) in Taiwan were much higher than in Chicago, Olympic and Ventura. The results suggest that there is a greater heavy metal elements problem in Taiwan. The average dry deposition fluxes of total-PAHs in Taiwan were 622, 529 and 575 Mum/m2/sec at these three sampling sites. These werehigher than reported in the Great Lakes, Siskiwit Lake and Chesapeake Bay, but were about the same as in Chicago. The total PAH composition at the traffic sampling sites were 7275, 839 and 2450 Mug/g for Taichung, Tainan and Pingtung, respectively. The Taichung traffic sampling site had a larger total-PAH composition than the other two sampling sites. The total-PAH compositions in the rural sampling sites were523, 645 and 531 Mug/g for Taichung, Tainan and Pingtung, respectively. There was no significant difference for PAHs at the rural site ofTaiwan. The cumulative fraction curve showed that atmospheric pollutants such as PAHs, sulfate, nitrate and heavy metals in Taiwan were mostly associated with fine particles (< 2.5 Mum). However, more than 95% of PCBs tended to be associated with particle size greater than 2.5 Mum. [ABSTRACT FROM AUTHOR]