Aerosol deposition velocity measurements on human body surfaces

Abstract. The increasing use of intensive agricultural practices can lead to damaging consequences for the atmosphere through enhanced emissions of air pollutants. However, there are few direct measurements of the surface–atmosphere exchange of trace gases and water-soluble aerosols over agricultural grassland, particularly of reactive nitrogen compounds. In this study, we present measurements of the concentrations, fluxes and deposition velocities of the trace gases HCl, HONO, HNO3, SO2 and NH3, and their associated water-soluble aerosol counterparts Cl−, NO2−, NO3−, SO42−, NH4+ as determined hourly for one month in May–June 2016 over agricultural grassland pre- and post-fertilisation. Measurements were made using the Gradient of Aerosols and Gases Online Registration (GRAEGOR) wet–chemical two–point gradient instrument. Emissions of NH3 peaked at 1460 ng m−2 s−1 three hours after fertilisation, with an emission of HONO peaking at 4.92 ng m−2 s−1 occurring five hours after fertilisation. Apparent emissions of NO3− aerosol were observed after fertilisation which, coupled with a divergence of HNO3 deposition velocity (Vd) from its theoretical maximum value, suggested the reaction of emitted NH3 with atmospheric HNO3 to form ammonium nitrate aerosol. The use of the conservative exchange fluxes of tot-NH4+ and tot-NO3− indicated net emission of tot-NO3−, implying a ground source of HNO3 after fertilisation. Daytime concentrations of HONO remained above the detection limit (30 ng m−3) throughout the campaign, suggesting a daytime source for HONO at the site. Whilst the mean Vd of NH4+ was with 0.93 mm/s in the range expected for the accumulation mode, the larger average Vd for Cl− (3.65 mm/s), NO3− (1.97 mm/s), SO42− (1.89 mm/s) reflected the contribution of a super-micron fraction and decreased with increasing PM2.5 / PM10 ratio (a proxy measurement for aerosol size), providing direct evidence of a size-dependence of aerosol deposition velocity for aerosol chemical compounds.

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Summary of ozone dry deposition velocity measurements and model estimates over vineyard, cotton, grass and deciduous forest in summer

Atmospheric Environment ◽

10.1016/1352-2310(95)00352-5 ◽

1996 ◽

Vol 30 (13) ◽

pp. 2363-2369 ◽

Cited By ~ 58

Author(s):

Jacob Padro

Keyword(s):

Dry Deposition ◽

Deciduous Forest ◽

Deposition Velocity ◽

Velocity Measurements ◽

Dry Deposition Velocity

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Surface–atmosphere exchange of inorganic water-soluble gases and associated ions in bulk aerosol above agricultural grassland pre- and postfertilisation

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-16953-2018 ◽

2018 ◽

Vol 18 (23) ◽

pp. 16953-16978 ◽

Cited By ~ 3

Author(s):

Robbie Ramsay ◽

Chiara F. Di Marco ◽

Mathew R. Heal ◽

Marsailidh M. Twigg ◽

Nicholas Cowan ◽

...

Keyword(s):

Trace Gases ◽

Deposition Velocity ◽

Agricultural Practices ◽

Aerosol Deposition ◽

Water Soluble ◽

Surface Atmosphere ◽

Deposition Velocities ◽

Ground Source ◽

Direct Measurements ◽

Proxy Measurement

Abstract. The increasing use of intensive agricultural practices can lead to damaging consequences for the atmosphere through enhanced emissions of air pollutants. However, there are few direct measurements of the surface–atmosphere exchange of trace gases and water-soluble aerosols over agricultural grassland, particularly of reactive nitrogen compounds. In this study, we present measurements of the concentrations, fluxes and deposition velocities of the trace gases HCl, HONO, HNO3, SO2 and NH3 as well as their associated water-soluble aerosol counterparts Cl−, NO2-, NO3-, SO42- and NH4+ as determined hourly for 1 month in May–June 2016 over agricultural grassland near Edinburgh, UK, pre- and postfertilisation. Measurements were made using the Gradient of Aerosols and Gases Online Registrator (GRAEGOR) wet-chemistry two-point gradient instrument. Emissions of NH3 peaked at 1460 ngm-2s-1 3 h after fertilisation, with an emission of HONO peaking at 4.92 ngm-2s-1 occurring 5 h after fertilisation. Apparent emissions of NO3- aerosol were observed after fertilisation which, coupled with a divergence of HNO3 deposition velocity (Vd) from its theoretical maximum value, suggested the reaction of emitted NH3 with atmospheric HNO3 to form ammonium nitrate aerosol. The use of the conservative exchange fluxes of tot-NH4+ and tot-NO3- indicated net emission of tot-NO3-, implying a ground source of HNO3 after fertilisation. Daytime concentrations of HONO remained above the detection limit (30 ng m−3) throughout the campaign, suggesting a daytime source for HONO at the site. Whilst the mean Vd of NH4+ was 0.93 mm s−1 in the range expected for the accumulation mode, the larger average Vd for Cl− (3.65 mm s−1), NO3- (1.97 mm s−1) and SO42- (1.89 mm s−1) reflected the contribution of a super-micron fraction and decreased with increasing PM2.5∕PM10 ratio (a proxy measurement for aerosol size), providing evidence – although limited by the use of a proxy for aerosol size – of a size dependence of aerosol deposition velocity for aerosol chemical compounds, which has been suggested from process-orientated models of aerosol deposition.

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Development and validation of a size-resolved particle dry deposition scheme for applications in aerosol transport models

Geoscientific Model Development Discussions ◽

10.5194/gmdd-3-1317-2010 ◽

2010 ◽

Vol 3 (3) ◽

pp. 1317-1357 ◽

Cited By ~ 3

Author(s):

A. Petroff ◽

L. Zhang

Keyword(s):

Dry Deposition ◽

Large Scale ◽

Climate Models ◽

Transport Model ◽

Deposition Velocity ◽

Coniferous Forest ◽

Aerosol Deposition ◽

Aerosol Transport ◽

Surface Deposition ◽

Development And Validation

Abstract. A size-resolved particle dry deposition scheme is developed, which has been designed for inclusion in large-scale air quality and climate models, where the size distribution and fate of the atmospheric aerosol is of concern. The "resistance" structure is similar to what is proposed by Zhang et al. (2001, 2003), while a new "surface" deposition velocity (or surface resistance) is derived by simplification of a one-dimensional aerosol transport model (Petroff et al., 2008b, 2009). Collection efficiencies are given for the 26 Land Use Categories that decribe the earth surface. Validation of this model with existing measurements is performed on desert, grass, coniferous forest and liquid water surfaces. A comparison of this model with measurements on snow and ice is also given. Even though a qualitative agreement is reached, further size-segegated measurements are needed in order to confirm the model accuracy on this surface. The present analytical model provides more accurate predictions of the aerosol deposition on these surfaces than previous models.

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Microstructural comparison of synthetic bioceramics with natural bioceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084491 ◽

1991 ◽

Vol 49 ◽

pp. 38-39

Author(s):

Shulin Wen ◽

Jingwei Feng ◽

A. Krajewski ◽

A. Ravaglioli

Keyword(s):

Recent Work ◽

Human Body ◽

Human Tissues ◽

Main Constituent ◽

Laboratory Furnace ◽

Chinese Adult ◽

Human Enamel ◽

Biological Compatibility ◽

Synthetic Hydroxyapatite ◽

Synthetic Work

Hydroxyapatite bioceramics has attracted many material scientists as it is the main constituent of the bone and the teeth in human body. The synthesis of the bioceramics has been performed for years. Nowadays, the synthetic work is not only focused on the hydroapatite but also on the fluorapatite and chlorapatite bioceramics since later materials have also biological compatibility with human tissues; and they may also be very promising for clinic purpose. However, in comparison of the synthetic bioceramics with natural one on microstructure, a great differences were observed according to our previous results. We have investigated these differences further in this work since they are very important to appraise the synthetic bioceramics for their clinic application.The synthetic hydroxyapatite and chlorapatite were prepared according to A. Krajewski and A. Ravaglioli and their recent work. The briquettes from different hydroxyapatite or chlorapatite powders were fired in a laboratory furnace at the temperature of 900-1300°C. The samples of human enamel selected for the comparison with synthetic bioceramics were from Chinese adult teeth.

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Study on erythrocytes by SEM photogrammetry (SEMP) technique

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161187 ◽

1990 ◽

Vol 48 (3) ◽

pp. 724-725

Author(s):

Tong Wensheng ◽

Lu Lianhuang ◽

Zhang Zhijun

Keyword(s):

Quantitative Analysis ◽

Cell Membrane ◽

Clinical Diagnosis ◽

Human Body ◽

Blood Cells ◽

Three Dimensional ◽

Normal Person ◽

Blood Disease ◽

Computation Technique ◽

Important Basis

This is a combined study of two diffirent branches, photogrammetry and morphology of blood cells. The three dimensional quantitative analysis of erythrocytes using SEMP technique, electron computation technique and photogrammetry theory has made it possible to push the study of mophology of blood cells from LM, TEM, SEM to a higher stage, that of SEM P. A new path has been broken for deeply study of morphology of blood cells.In medical view, the abnormality of the quality and quantity of erythrocytes is one of the important changes of blood disease. It shows the abnormal blood—making function of the human body. Therefore, the study of the change of shape on erythrocytes is the indispensable and important basis of reference in the clinical diagnosis and research of blood disease.The erythrocytes of one normal person, three PNH Patients and one AA patient were used in this experiment. This research determines the following items: Height;Length of two axes (long and short), ratio; Crevice in depth and width of cell membrane; Circumference of erythrocytes; Isoline map of erythrocytes; Section map of erythrocytes.

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