Modelling Dust Emissions from a Source Using Dust Monitoring and Meteorological Data

This paper describes a study into the development of more robust dust emission factors by means of dust and meteorological monitoring. Emission factors for nuisance dusts in the literature are scarce, with estimates of dust output given for many processes in mass per unit area per year. Temporal variations and the extent and conditions in which maximum concentrations occur can therefore be impossible to predict with any accuracy. This investigation aims to improve predic-tions by “back calculating” emission levels based on dust monitoring around known dust sources. Nuisance dust and meteorological monitoring has been undertaken at a sand and gravel quarry in the UK for a consecutive period of two years. Sticky pad directional dust monitors were used to collect dust at eight locations at and around the site with meteorological data collected at an elec-tronic weather station within the site. Air quality modelling software (ADMS) was used to test emission factors from the European Environment Agency (EEA) and the US Environmental Protec-tion Agency (EPA) for emissions from mineral workings. Predictions were compared with the dust monitoring data to assess accuracy, with results showing limited poor correspondence (r2 < 0.3). Trends showed that emission predictions were poorest in winter;this is likely because most emis-sion calculations are not weather dependent and seasonal fluctuations will occur. Dust emission rate calculations were altered with respect to the dust monitoring data for one monitoring location on the mineral site boundary and the model was run again. Results were then tested at two different locations up to 200 m from the site boundary, with very positive correlations (r2 0.89) and similar maximum concentrations (<5% difference). This study has therefore shown that ac-curate site-specific emission rates can be produced in combination with site boundary sticky pad dust monitoring in order to accurately derive estimations elsewhere.

Dust dispersion and management in underground mining faces

Presence of fine dust in air causes serious health hazard for mine operators resulting in such serious problems as coal workers’pneumoconiosis and silicosis.Major sources of dust appear of course along the mining face where the minerals are extracted.Proper control and management are required to ensure safe working environment in the mine.Here,we utilize the computational fluid dynamic(CFD)approach to evaluate various methods used for mitigating dust dispersion from the mining face and for ensuring safe level of dust concentration in the mine tunnel for safety of the operators.The methods used include:application of blowing and exhaust fans,application of brattice and combination of both.The results suggest that among the examined methods,implementation of appropriately located brattice to direct the flow from the main shaft to the mining face is the most effective method to direct dust particles away from the mining face.

Simulating Dry Deposition Fluxes of PM_(10) and Particulate Inorganic Nitrogen over the Eastern China Seas During a Severe Asian Dust Event Using WRF-Chem Model

A WRF-Chem model including a comprehensive gas-phase nitrogen chemistry module was used to simulate a severe dust event appearing in the eastern China on 19-25 March, 2002. The modeling result well reproduced PM10 concentrations in various distances from the dust sources and the transport pathway of the dust strom. The results showed that both the concentrations and the dry deposition fluxes of PM10 increased over the China seas during the dust event following the passage of a cold front system. The maximum fluxes of PM10 in the Yellow Sea and the East China Sea during the dust event were 5.5 and 8.4 times of those before the event, respectively. However, the temporal variations of the dry deposition fluxes of particulate inorganic nitrogen differed over the Yellow Sea from those over the East China Sea. Nitrate and ammonium in the whole northern China rapidly decreased because of the intrusion of dust-loaded air on 19 March. The dust plume arrived in the Yellow Sea on 20 March, decreasing the particulate inorganic nitrogen in mass concentration accordingly. The minimum dry deposition fluxes of nitrate and ammonium in the Yellow Sea were about 3/5 and 1/6 of those before the dust arrival, respectively. In contrast, when the dust plume crossed over the Yangtze Delta area, it became abundant in nitrate and ammonium and increased the concentrations and dry deposition fluxes of particulate inorganic nitrogen over the East China Sea, where the maximum dry deposition fluxes of nitrate and ammonium increased approximately by 4.1 and 2.6 times of those prior to the dust arrival.

Modeling Tensile Strength of Concrete on Partial Replacement of Ce­ment and Sand with Quarry Dust Ground Granulated Blast Furnace and Slag Silica Fumes

Tensile strength of concrete were examined on its partial replacement of cement and sand using ground granulated blast furnace and quarry dust.The study examines its behaviour at different dimensions.This is to monitor the variation effect of these parameters on the growth rates of tensile to the optimum curing age.These include non linear conditions of tensile state,non-elastic and its brittle behaviour at all times as it express zero conditions in tension.This means that it has the ability to with stand pull force.It also reflects its weak ability to handle shear stress thus tends to cause deformation in material as it has poor elasticity.The reflection of its brittle influence the rate of tensile behaviour from concrete ductility.These are known to be a material on modern mechanics of concrete.These are also considered as quasi brittle material.This behaviour was reflected as the system considered evaluating the growth rate of tensile strength that replaced cement and sand with these locally sourced addictives.The developed model monitor other reflected influential parameters such as variation of concrete porosity due it compaction in placements,tensile behaviour reflects these effect that subject it to mechanical properties of concrete.The study expressed the reaction of these parameters in the simulation,the evaluation of these affected the details variation of tensile growth rate at different water cement ratios and curing age.The tensile behaviour that was monitored are based on these factors in the study.The derived model were validated with the a researcher results[24],and both parameters developed best fits correlation.The study is imperative because the system expressed the behaviour of tensile strength from concrete at different dimensions.Experts can applied these concept to monitor tensile behaviour considering these parameters in its growth rates.

FGF2 is overexpressed in asthma and promotes airway in airway epithelial cells

Background: Airway inflammation is the core pathological process of asthma, with the key inflammatory regulators incompletely defined. Recently, fibroblast growth factor 2(FGF2) has been reported to be an inflammatory regulator;however, its role in asthma remains elusive. This study aimed to investigate the immunomodulatory role of FGF2 in asthma.Methods: First, FGF2 expression was characterised in clinical asthma samples and the house dust mite(HDM)-induced mouse chronic asthma model. Second, recombinant mouse FGF2(rm-FGF2) protein was intranasally delivered to determine the effect of FGF2 on airway inflammatory cell infiltration. Third, human airway epithelium-derived A549 cells were stimulated with either HDM or recombinant human interleukin-1β(IL-1β) protein combined with or without recombinant human FGF2. IL-1β-induced IL-6 or IL-8 release levels were determined using enzyme-linked immunosorbent assay, and the involved signalling transduction was explored via Western blotting.Results: Compared with the control groups, the FGF2 protein levels were significantly upregulated in the bronchial epithelium and alveolar areas of clinical asthma samples [(6.70±1.79) vs.(16.32±2.40), P=0.0184;(11.20±2.11) vs.(21.00±3.00), P=0.033, respectively] and HDM-induced asthmatic mouse lung lysates [(1.00±0.15) vs.(5.14±0.42),P<0.001]. Moreover, FGF2 protein abundance was positively correlated with serum total and anti-HDM IgE levels in the HDM-induced chronic asthma model(R^(2)=0.857 and 0.783, P=0.0008 and 0.0043, respectively). Elevated FGF2protein was mainly expressed in asthmatic bronchial epithelium and alveolar areas and partly co-localised with infiltrated inflammatory cell populations in HDM-induced asthmatic mice. More importantly, intranasal instillation of rm-FGF2 aggravated airway inflammatory cell infiltration [(2.45±0.09) vs.(2.88±0.14), P=0.0288] and recruited more subepithelial neutrophils after HDM challenge [(110.20±29.43) cells/mm^(2) vs.(238.10±42.77) cells/mm^(2), P=0.0392]without affecting serum IgE levels and Th2 cytokine transcription. In A549 cells, FGF2 was upregulated through HDM stimulation and promoted IL-1β-induced IL-6 or IL-8 release levels [up to(1.41±0.12)-or(1.44±0.14)-fold change vs.IL-1β alone groups, P=0.001 or 0.0344, respectively]. The pro-inflammatory effect of FGF2 is likely mediated through the fibroblast growth factor receptor(FGFR)/mitogen-activated protein kinase(MAPK)/nuclear factor kappa B(NF-κB)pathway.Conclusions: Our findings suggest that FGF2 is a potential inflammatory modulator in asthma, which can be induced by HDM and acts through the FGFR/MAPK/NF-κB pathway in the airway epithelial cells.

Modeling the influence of forced ventilation on the dispersion of droplets ejected from roadheader-mounted external sprayer

In order to reveal the influence of forced ventilation on the dispersion of droplets ejected from roadheader-mounted external sprayer,the paper studies the air-flowing field and the droplet distribution under the condition of gentle breeze and normal forced ventilation in heading face using the particle tracking technology of computational fluid dynamics(CFD).The results show that air-flowing tendency in the same section presents great comparability in the period of gentle breeze and forced ventilation,and the difference mainly embodies in the different wind velocity.The influence of ventilation on the dispersion of droplets is faint under the gentle breeze condition.The droplet can be evenly distributed around the cutting head.However,under the normal forced ventilation,a large number of droplets will drift to the return air side.At the same time,droplet clusters are predominantly presented in the lower part of windward side and the middle of the leeward side around the cutting head.In contrast,the droplet concentration in other parts around cutting head decreases a lot and the droplets are unable to form close-grained mist curtain.So the dust escape channel is formed.In addition,the simulation results also reveal that the disturbance of air flow on the droplet distribution can be effectively relieved when using ventilation duct with Coanda effect(VDCE).Field experiment results show that the dust suppression efficiency of total dust and respirable dust increases respectively by 10.5%and 9.3%when using VDCE,which proves that it can weaken the influence of airflow on droplet dispersion.

An Overview of Mineral Dust Modeling over East Asia

East Asian dust（EAD） exerts considerable impacts on the energy balance and climate/climate change of the earth system through its influence on solar and terrestrial radiation, cloud properties, and precipitation efficiency. Providing an accurate description of the life cycle and climate effects of EAD is therefore critical to better understanding of climate change and socioeconomic development in East Asia and even worldwide. Dust modeling has undergone substantial development since the late 1990 s, associated with improved understanding of the role of EAD in the earth system. Here, we review the achievements and progress made in recent decades in terms of dust modeling research,including dust emissions, long-range transport, radiative forcing（RF）, and climate effects of dust particles over East Asia. Numerous efforts in dust/EAD modeling have been directed towards furnishing more sophisticated physical and chemical processes into the models on higher spatial resolutions. Meanwhile, more systematic observations and more advanced retrieval methods for instruments that address EAD related science issues have made it possible to evaluate model results and quantify the role of EAD in the earth system, and to further reduce the uncertainties in EAD simulations. Though much progress has been made, large discrepancies and knowledge gaps still exist among EAD simulations. The deficiencies and limitations that pertain to the performance of the EAD simulations referred to in the present study are also discussed.

Numerical analysis for contribution of the Tibetan Plateau to dust aerosols in the atmosphere over the East Asia

Although the Tibetan Plateau is widely thought as a potential dust source to the atmosphere over East Asia,little is known about the temporal changes of Tibetan dust activities and Tibetan dust source strength.In this study,we address these two issues by analyzing dust storm frequencies and aerosol index through remote sensing data and by means of numerical simulation.The findings indicate that monthly dust profiles over the Tibetan Plateau vary significantly with time.Near the surface,dust concentration increases from October,reaches its maximum in February March,and then decreases.In the middle to upper troposphere,dust concentration increases from January,reaches its maximum in May June,and decreases thereafter.Although Tibetan dust sources are important contributors to dust in the atmosphere over the Tibetan Plateau,their contribution to dust in the troposphere over eastern China is weaker.The contribution of Tibetan dust sources to dust in the atmosphere over the Tibetan Plateau decreases sharply with height,from 69% at the surface,40% in the lower troposphere,and 5% in the middle troposphere.Furthermore,the contribution shows seasonal changes,with dust sources at the surface at approximately 80% between November and May and 45% between June and September;in the middle and upper troposphere,dust sources are between 21% from February to March and less than 5% in the other months.Overall,dust aerosols originating from the Tibetan Plateau contribute to less than 10% of dust in East Asia.

Modeling heterogeneous chemical processes on aerosol surface

To explore the possible impact of heterogeneous chemical processes on atmospheric trace components, a coupled box model including gas-phase chemical processes, aerosol thermodynamic equilibrium processes, and heterogeneous chemical processes on the surface of dust, black carbon （BC） and sea salt is set up to simulate the effects of heterogeneous chemistry on the aerosol surface, and analyze the primary factors affecting the heterogeneous processes. Results indicate that heterogeneous chemical processes on the aerosol surface in the atmosphere will affect the concentrations of trace gases such as H2O2, HO2, O3, NO2, NO3, HNO3 and SO2, and aerosols such as SO42-, NO3- and NH4＋. Sensitivity tests suggest that the magnitude of the impact of heterogeneous processes strongly depends on aerosol concentration and the surface uptake coefficients used in the box model. However, the impact of temperature on heterogeneous chemical processes is considerably less. The ＂renoxification＂ of HNO3 will affect the components of the troPosPhere such as nitrogen oxide and ozone.