Dry deposition fluxes and deposition velocities of seven trace metal species at five sites in central Taiwan – a summary of surrogate surface measurements and a comparison with model estimations

Zhang, Leiming; Fang, Guor‐Cheng; Liu, C. K.; Huang, Yajing; Huang, Jen‐Chieh; Huang, Chao-Yang

doi:10.5194/acp-12-3405-2012

Cited by 32 publications

(20 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The PBM dry deposition fluxes presented in this study are likely conservative estimates since the ambient data collected by a Tekran instrument excluded coarse particle Hg. As shown in a recent study on trace metal dry deposition, coarse particles play an important and sometimes dominate role in the dry deposition budget (Zhang et al, 2012b). Assuming 30 % of the total PBM is in coarse particles (Landis and Keeler, 2002), PBM dry deposition needs to be adjusted by a factor of 2 or more depending on the actual particle size distribution, considering that coarse particle V d might be substantially higher than fine particle V d .…”

Section: Potential Uncertainties In the Estimated Dry Depositionmentioning

confidence: 99%

Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America

Zhang

Blanchard

Prestbo³

et al. 2012

Atmos. Chem. Phys.

Self Cite

129

View full text Add to dashboard Cite

Dry deposition of speciated mercury, i.e., gaseous oxidized mercury (GOM), particulate-bound mercury (PBM), and gaseous elemental mercury (GEM), was estimated for the year 2008–2009 at 19 monitoring locations in eastern and central North America. Dry deposition estimates were obtained by combining monitored two- to four-hourly speciated ambient concentrations with modeled hourly dry deposition velocities (Vd) calculated using forecasted meteorology. Annual dry deposition of GOM+PBM was estimated to be in the range of 0.4 to 8.1 μg m−2 at these locations with GOM deposition being mostly five to ten times higher than PBM deposition, due to their different modeled Vd values. Net annual GEM dry deposition was estimated to be in the range of 5 to 26 μg m−2 at 18 sites and 33 μg m−2 at one site. The estimated dry deposition agrees very well with limited surrogate-surface dry deposition measurements of GOM and PBM, and also agrees with litterfall mercury measurements conducted at multiple locations in eastern and central North America. This study suggests that GEM contributes much more than GOM+PBM to the total dry deposition at the majority of the sites considered here; the only exception is at locations close to significant point sources where GEM and GOM+PBM contribute equally to the total dry deposition. The relative magnitude of the speciated dry deposition and their good comparisons with litterfall deposition suggest that mercury in litterfall originates primarily from GEM, which is consistent with the limited number of previous field studies. The study also supports previous analyses suggesting that total dry deposition of mercury is equal to, if not more important than, wet deposition of mercury on a regional scale in eastern North America

show abstract

Section: Potential Uncertainties In the Estimated Dry Depositionmentioning

confidence: 99%

Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America

Zhang

Blanchard

Prestbo³

et al. 2012

Atmos. Chem. Phys.

Self Cite

129

View full text Add to dashboard Cite

show abstract

“…The original version of Zhang et al (2001) used 15 land use categories (LUCs) and was later extended to 26 LUCs, consistent with those used in Zhang et al (2003) (see Supporting Information of Zhang et al, 2012). The 26 LUCs were also used in the present study, although they were put into different groups (Sect.…”

Section: Methodsmentioning

confidence: 99%

“…However, small particles have very low mass fractions and thus small contributions to the bulk V d . Following the findings of Zhang et al (2012), the new algorithm should be developed for calculating V d of PM 2.5 , PM 2.5−10 and PM 10+ , instead of for specific particle species, and be applicable to various natural surfaces. The new algorithm is expected to produce similar V d values to the original sizeresolved scheme, but is much easier to implement at atmospheric deposition monitoring networks.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: An empirical algorithm estimating dry deposition velocity of fine, coarse and giant particles

Zhang

Zhao

2014

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract. An empirical algorithm is developed for calculating bulk dry deposition velocity (V d ) of fine (PM 2.5 -particles having a diameter of ≤ 2.5 µm), coarse (PM 2.5−10 -particles having a diameter of 2.5-10 µm), and giant (PM 10+ -particles having a diameter of > 10 µm) atmospheric particles. The algorithm is developed from an empirical fit of V d data calculated using the size-resolved V d scheme of Zhang et al. (2001) with assumed lognormal size distributions of PM 2.5 , PM 2.5−10 and PM 10+ . In the new algorithm, the surface deposition velocity (V ds ) is parameterized as a simple linear function of friction velocity (u * ) for PM 2.5 and as a polynomial function of u * for both PM 2.5−10 and PM 10+ over all the 26 land use categories (LUCs). An adjustment factor as an exponential function of u * and leaf area index (LAI) is also applied to V ds of PM 2.5−10 and PM 10+ over 9 of the 26 LUCs that have variable LAI. Constant gravitational settling velocities are provided for PM 2.5 , PM 2.5−10 and PM 10+ . Aerodynamic resistance between a reference height and the surface can be calculated using available analytical formulas from the literature. The bulk V d of PM 2.5 , PM 2.5−10 and PM 10+ at the reference height can then be calculated by combining the gravitational settling velocity, aerodynamic resistance and the parameterized V ds . V d values calculated using the new algorithm are within ±20 % of those using the original size-resolved scheme for fine, coarse and giant particles. Uncertainties in V d values from the new algorithm due to the pre-assumed size distributions are on the order of 20 % for fine particles and on the order of a factor of 2.0 for coarse and giant particles. The new algorithm provides an alternative approach for calculating V d of bulk aerosol particles. V d of any particulate species can be simply estimated using this scheme as long as the mass fractions in fine, coarse and giant particles are known or can be assumed.

show abstract

“…Besides for these point emission sources, trace metals concentrations could be originated from mobile sources (von Schneidemesser et al, 2010), especially in central Taiwan where heavy traffic occurs frequently. Details of these sampling sites have been elaborated by and Zhang et al (2012).…”

Section: Sampling Sitesmentioning

confidence: 99%

“…Previous studies at these sites focused on the comparison of dry deposition velocities of trace metals from model calculation and surrogate surfaces measurements Zhang et al, 2012). Additionally, meteorological data, including air temperature, relative humidity, wind speed, and wind direction, were also measured at individual sites.…”

Section: Introductionmentioning

confidence: 99%

Ambient Trace Metals Sources in Taichung, Taiwan: Principal Component Analysis

Huang

Chen

Liu

et al. 2013

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

There were eight trace metals, including As, Hg, Mn, Fe, Zn, Cr, Cu, and Pb, measured in the total suspended particles collected in central Taiwan using PS-1 samplers at five different sites. Overall, these trace metal concentrations were lower in summer than other seasons, and higher in industrial areas than in wetland. Principal Component Analysis (PCA) was utilized to identify the pollutant sources for each site. Three distinct sources were found in this study, and the results suggest that mobile sources were the main factor contributing to Mn, Fe, Zn, and Cr emissions, which were mainly from urban areas and in the vicinity of highways intersections. Within addition, municipal solid waste incinerators are significantly associated with emissions of As, Hg, Cu, and Pb. Finally, smelters were associated with high Hg, As, Fe, and Zn emissions from local industrial areas. However, contributions from two known point sources, a coal-fired power plant and a steeling plant could not be distinguished from the PCA results. This may be due to the prevailing wind directions and limitations of the measurements used in this work. These two sources are located to the west of these sampling sites, while the prevailing wind direction in this area was southwest.

show abstract

Dry deposition fluxes and deposition velocities of seven trace metal species at five sites in central Taiwan – a summary of surrogate surface measurements and a comparison with model estimations

Cited by 32 publications

References 49 publications

Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America

Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America

Technical Note: An empirical algorithm estimating dry deposition velocity of fine, coarse and giant particles

Ambient Trace Metals Sources in Taichung, Taiwan: Principal Component Analysis

Contact Info

Product

Resources

About