Dispersion and dry and wet deposition of PAHs in an atmospheric environment

2006 ◽  
Vol 53 (2) ◽  
pp. 215-224 ◽  
Author(s):  
N. Ozaki ◽  
K. Nitta ◽  
T. Fukushima
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Atmospheric Environment ◽  
Coarse Particles ◽  
Atmospheric Concentration ◽  
Dry And Wet Deposition ◽  
Total Pahs ◽  
Polycyclic Aromatic ◽  
Rainy Days

The atmospheric concentration and dry and wet deposition were measured for particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) from August to December in Higashi-Hiroshima City, Japan. PM concentration of fine particles (0.6–7 μm) was 5.7–75.1 μg m−3, and coarse particles (>7 μm) was 2.2–22.3 μg m−3. Total PAHs concentration of fine particles was 0.14–16.3 ng m−3, and coarse particles was 0.01–0.77 ng m−3. Their concentration increased on non-rainy days and decreased rapidly on rainy days. For seasonal fluctuations of PAHs, their concentrations decreased from summer to winter, and the rate of decrease was more distinct for fine particles. For total (dry+wet) depositions, the PM flux was 1.9–11.2 mg m−2 d−1, and the total PAHs flux was 1.9–97.2 ng m−3 d−1. From these measurements, the yearly total loading of PAHs was estimated for the particle phase. Total loading was 28 μg m−2 y−1 for the dry deposition and 52 mg m−2 y−1 for the wet deposition. The loading of the wet deposition was comparable to those of the dry deposition for all ring numbers.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2014 ◽  
Vol 14 (5) ◽  
pp. 2233-2244 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractionated particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume-weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban North America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, as well as nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium, and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of the HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer, while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal, with two peaks in the bins of < 0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2013 ◽  
Vol 13 (11) ◽  
pp. 28309-28341 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractioned particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, and nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal with two peaks in the bins of <0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Plant assemblages in atmospheric deposition

2019 ◽  
Author(s):  
Ke Dong ◽  
Cheolwoon Woo ◽  
Naomichi Yamamoto
Keyword(s):  
Atmospheric Deposition ◽  
Dry Deposition ◽  
Wet Deposition ◽  
High Throughput Sequencing ◽  
Sampling Site ◽  
Its2 Region ◽  
Dry And Wet Deposition ◽  
Custom Made ◽  
Plant Assemblages ◽  
Cloud Scavenging

Abstract. Plants disperse spores, pollen, and fragments into the atmosphere. The emitted plant particles return to the pedosphere by sedimentation (dry deposition) and/or by precipitation (wet deposition) and constitute part of the global cycle of substances. However, little is known regarding the taxonomic diversities and flux densities of plant particles deposited from the atmosphere. Here, plant assemblages were examined in atmospheric deposits collected in Seoul in South Korea. A custom-made automatic sampler was used to collect dry and wet deposition samples for which plant assemblages and quantities were determined using high-throughput sequencing and quantitative PCR with universal plant-specific primers targeting the internal transcribed spacer 2 (ITS2) region. Dry deposition was dominant for atmospheric deposition of plant particles (87 %). The remaining 13 % was deposited by precipitation, i.e., wet deposition, via rainout (in-cloud scavenging) and/or washout (below-cloud scavenging). Plant assemblage structures did not differ significantly between dry and wet deposition, indicating that washout, which is likely taxon-independent, predominated rainout, which is likely taxon-dependent, for wet deposition of atmospheric plant particles. A small number of plant genera were detected only in wet deposition, indicating that they might be specifically involved in precipitation through acting as nucleation sites in the atmosphere. Future interannual monitoring will control for the seasonality of atmospheric plant assemblages observed at our sampling site. Future global monitoring is also proposed to investigate geographical differences and investigate whether endemic species are involved in plant-mediated bioprecipitation in regional ecological systems.

scholarly journals Dry and wet deposition of inorganic nitrogen compounds to a tropical pasture site (Rondônia, Brazil)

2006 ◽  
Vol 6 (2) ◽  
pp. 447-469 ◽  
Author(s):  
I. Trebs ◽  
L. L. Lara ◽  
L. M. M. Zeri ◽  
L. V. Gatti ◽  
P. Artaxo ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Particle Deposition ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Deposition Fluxes ◽  
Dry And Wet Deposition ◽  
Surface Atmosphere ◽  
Nh3 Emission

Abstract. The input of nitrogen (N) to ecosystems has increased dramatically over the past decades. While total (wet + dry) N deposition has been extensively determined in temperate regions, only very few data sets of N wet deposition exist for tropical ecosystems, and moreover, reliable experimental information about N dry deposition in tropical environments is lacking. In this study we estimate dry and wet deposition of inorganic N for a remote pasture site in the Amazon Basin based on in-situ measurements. The measurements covered the late dry (biomass burning) season, a transition period and the onset of the wet season (clean conditions) (12 September to 14 November 2002) and were a part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign. Ammonia (NH3), nitric acid (HNO3), nitrous acid (HONO), nitrogen dioxide (NO2), nitric oxide (NO), ozone (O3), aerosol ammonium (NH4+) and aerosol nitrate (NO3-) were measured in real-time, accompanied by simultaneous meteorological measurements. Dry deposition fluxes of NO2 and HNO3 are inferred using the ''big leaf multiple resistance approach'' and particle deposition fluxes are derived using an established empirical parameterization. Bi-directional surface-atmosphere exchange fluxes of NH3 and HONO are estimated by applying a ''canopy compensation point model''. N dry and wet deposition is dominated by NH3 and NH4+, which is largely the consequence of biomass burning during the dry season. The grass surface appeared to have a strong potential for daytime NH3 emission, owing to high canopy compensation points, which are related to high surface temperatures and to direct NH3 emissions from cattle excreta. NO2 also significantly accounted for N dry deposition, whereas HNO3, HONO and N-containing aerosol species were only minor contributors. Ignoring NH3 emission from the vegetation surface, the annual net N deposition rate is estimated to be about −11 kgN ha-1 yr-1. If on the other hand, surface-atmosphere exchange of NH3 is considered to be bi-directional, the annual net N budget at the pasture site is estimated to range from −2.15 to −4.25 kgN ha-1 yr-1.

scholarly journals The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

2014 ◽  
Vol 14 (9) ◽  
pp. 13731-13767 ◽  
Author(s):  
C. Knote ◽  
A. Hodzic ◽  
J. L. Jimenez
Keyword(s):  
Gas Phase ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Water Solubility ◽  
Transport Model ◽  
Chemistry Transport Model ◽  
Dry And Wet Deposition ◽  
Modeling Systems ◽  
Sensitivity Studies ◽  
Wet Removal

Abstract. The effect of dry and wet deposition of semi-volatile organic compounds (SVOC) in the gas-phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the regional chemistry transport model WRF-Chem, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48% and 63% respectively over the continental US Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40% vs. −8% for anthropogenics, −52% vs. −11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas-phase (61% for anthropogenics, 76% for biogenics). A number of sensitivity studies shows that this is a robust feature of the modeling system. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in some current modeling systems (H* = 105 M atm−1; H* = H* (HNO3)) still lead to an overestimation of 25% / 10% compared to our best estimate. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations.

Polycyclic aromatic hydrocarbons (PAHs) in fine and coarse particles

2013 ◽  
Vol 12 (1) ◽  
pp. 63-70
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Fine Particles ◽  
Gas Chromatography Mass Spectrometry ◽  
Diagnostic Ratios ◽  
Coarse Particles ◽  
Polycyclic Aromatic ◽  
The Mean ◽  
Short Time

<p>About 140 samplings of fine and coarse particles were gathered during the year 2006 in Kozani that represent an urban area surrounded by opencast coal mining. A low volume dichotomus sampler has been used to trap suspended particles. The filters used were teflon, which are ideal for analysis in the determination of PAHs. The determination of Polycyclic Aromatic Hydrocarbons (PAHs) has been carried out by the use of the analytic technique of large volume injection and gas chromatography – mass spectrometry (LVI - GC/MS). The extraction of substances has been made in a two stage procedure, firstly with agitation in a magnetic shaker and secondly by the use of ultrasonic bath. This technique has given high recoveries of PAHs, in short time intervals. The mean daily concentrations of fine particles varied from 4 to 48 μg m-3 and annual mean was 16 μg m-3. The mean daily concentrations of coarse particles respectively varied from 2 to 67 μg m-3 with 23 μg m-3 annual mean concentration. The ΣPAH concentrations for fine samples were 4.80 ± 7.06 ng m-3 and for coarse samples were 1.36 ± 1.59 ng m-3. The mean B[a]Py concentration for fine particles was 0.38 ng m-3. Finally, diagnostic ratios were used to characterize and identify PAHs emission source in this study.</p>

scholarly journals The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

2015 ◽  
Vol 15 (1) ◽  
pp. 1-18 ◽  
Author(s):  
C. Knote ◽  
A. Hodzic ◽  
J. L. Jimenez
Keyword(s):  
Gas Phase ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Water Solubility ◽  
Transport Model ◽  
Dry And Wet Deposition ◽  
Modeling Systems ◽  
Sensitivity Studies ◽  
Made In ◽  
Wet Removal

Abstract. The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs) in the gas phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40 vs. −8% for anthropogenics, and −52 vs. −11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics). Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in some current modeling systems (H* = H* (CH3COOH); H* = 105 M atm−1; H* = H* (HNO3)) still lead to an overestimation of 35%/25%/10% compared to our best estimate.

scholarly journals Effects of carbonaceous materials and particle size on oral and inhalation bioaccessibility of PAHs and OPEs in airborne particles

2021 ◽  
Author(s):  
Yuan Zeng ◽  
shejun Chen ◽  
Yun Fan ◽  
Qiqi Li ◽  
Yufeng Guan ◽  
...  
Keyword(s):  
Particle Size ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Airborne Particles ◽  
Coarse Particles ◽  
Strongly Correlated ◽  
Oral Bioaccessibility ◽  
Polycyclic Aromatic ◽  
Potential Factors ◽  
Scientific Attention

Abstract Bioavailability of environmental contaminants is attracting considerable scientific attention due to growing awareness of its importance for risk assessment. In this study, potential factors governing bioaccessibility of airborne particles-bound polycyclic aromatic hydrocarbons (PAHs) and organophosphorus esters (OPEs) in stimulated gastrointestinal and respiratory tracts were elucidated. Particle concentrations of PAHs and OPEs at the eight sites were 2.4−32.3 ng/m3 and 1.6−19.9 ng/m3, respectively. In fine particles (with aerodynamic diameter less than 2.5 µm), 4- to 6-ring PAHs were more strongly correlated with organic carbon (OC) than elemental carbon (EC); while 3- and 4-ring PAHs in coarse particles (2.5−10 µm) tended to associate with EC. OPEs mostly showed significant correlations with EC in both fine and coarse particles. OC and EC exerted a significantly restraining effect on the oral and inhalation bioaccessibility of most HOCs in fine particles due to sorption of HOC molecules to these components. Furthermore, the effects varied, which could depend either on the emission sources (for oral bioaccessibility of PAHs) or the physicochemical properties of HOCs (for bioaccessibility of OPEs and inhalation bioaccessibility of PAHs). Linear regression indicated that EC should play a more important role in the inhalation bioaccessibility than the oral bioaccessibility. Particle size of airborne particles is a relatively less significant factor determining the bioaccessibility.

scholarly journals Chemical Composition and Deposition Fluxes of Water-Soluble Inorganic Ions on Dry and Wet Deposition Samples in Wuhan, China

2019 ◽  
Vol 16 (1) ◽  
pp. 132 ◽  
Author(s):  
Jun Qin ◽  
Yassin Mbululo ◽  
Muyi Yang ◽  
Zhengxuan Yuan ◽  
Fatuma Nyihirani ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Inversion Layer ◽  
Inorganic Ions ◽  
Average Concentration ◽  
Water Soluble ◽  
Deposition Flux ◽  
Dry And Wet Deposition ◽  
Strong Inversion ◽  
Water Soluble Inorganic Ions

Measurement of PM2.5 concentration, dry and wet deposition of water-soluble inorganic ions (WSII) and their deposition flux was carried out. During sampling, a total number of 31 samples of PM2.5, five wet deposition samples and seven dry deposition samples were collected. The analyses results showed that the average concentration of PM2.5 was 122.95 µg/m3 whilst that of WSII was 51.63 µg/m3, equivalent to 42% of the total mass of PM2.5. The correlation coefficients between WSII in samples of PM2.5 was significant (r = 0.50 and p-value of 0.0019). Ions of   SO 4 2 − , NO 3 − , Cl − , and   NH 4 + were dominant in the entire samples (PM2.5, dry and wet depositions), nevertheless, the average concentration of both SO 4 2 − and Cl − were below the China environmental quality standard for surface water. The ratio of dominant anions in wet deposition ( SO 4 2 − / NO 3 − ) was 1.59, whilst that for dry deposition ( SO 4 2 − / Cl − ) was 1.4, indicating that acidity was mainly derived from sulphate. In the case of dominant cations, the dry and wet deposition ratios ( Ca 2 + / NH 4 + ) were 1.36 and 1.37, respectively, suggesting the alkaline substances were mainly dominated by calcium salts. Days with higher recorded concentrations of PM2.5 were accompanied by dry and warm boundary layer structure, weak low-level wind and strong inversion layer.

Simulation of Sulfur Deposition from Power Plants in Henan Province, China

2011 ◽  
Vol 356-360 ◽  
pp. 712-716
Author(s):  
Hong Wei Tian ◽  
Wei Deng ◽  
Lin Mao Ye
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Power Plants ◽  
Grid Point ◽  
Henan Province ◽  
Sulfur Deposition ◽  
Dry And Wet Deposition ◽  
Annual Flux

Dry deposition and wet remove of sulfur from main power plants plan to build in Henan province of China were numerically simulated with CALPUFF based on estimated SO2emissions of each plant. The results of simulation shows that, the highest grid point annual dry deposition and wet remove quantity of sulfur from power plants reaches 554.498kg/km2and 457.745kg/km2respectively. Annual dry deposition and wet remove of sulfur in Henan region can reaches to 8381.422 ton and 4974.747 ton respectively. Zhengzhou was the most heavily impacted city by dry deposition and wet remove of sulfur from power plants, and annual flux of dry deposition and wet remove can reach to 366.953kg/km2and 188.743kg/km2 respectively. After the completion of construction of new plants and the closing down of old ones, dry and wet deposition in most region of HenanSuperscript textprovince declined, and 4642.220 ton of dry deposition and 2405.216 ton of wet deposition were lessened annually according to the simulation.

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