Assessing the Impact of Fugitive Dust Emissions from Cement Silos at Cluster of Concrete Batching Facilities Using Air Dispersion Modeling

This research assessed the environmental impact of cement silos emission on the existing concrete batching facilities in M35-Mussafah, Abu Dhabi, United Arab Emirates. These assessments were conducted using an air quality dispersion model (AERMOD) to predict the ambient concentration of Portland Cement particulate matter less than 10 microns (PM10) emitted to the atmosphere during loading and unloading activities from 176 silos located in 25 concrete batching facilities. AERMOD was applied to simulate and describe the dispersion of PM10 released from the cement silos into the air. Simulations were carried out for PM10 emissions on controlled and uncontrolled cement silos scenarios. Results showed an incremental negative impact on air quality and public health from uncontrolled silos emissions and estimated that the uncontrolled PM10 emission sources contribute to air pollution by 528958.32 kg/Year. The modeling comparison between the controlled and uncontrolled silos shows that the highest annual average concentration from controlled cement silos is 0.065 μg/m3, and the highest daily emission value is 0.6 μg/m3;both values are negligible and will not lead to significant air quality impact in the entire study domain. However, the uncontrolled cement silos’ highest annual average concentration value is 328.08 μg/m3. The highest daily emission average value was 1250.09 μg/m3;this might cause a significant air pollution quality impact and health effects on the public and workers. The short-term and long-term average PM10 pollutant concentrations at these receptors predicted by the air dispersion model are discussed for both scenarios and compared with local and international air quality standards and guidelines.

Using ADMS models for Air Quality Assessment and Management in China

ADMS-Urban is the most widely used advanced dispersion model for urban areas, being used extensively in China and worldwide, providing a practical tool for assessing and managing urban air quality. In this paper we briefly describe the ADMS dispersion models and give an overview of their use in China. And it describes in more detail the use of ADMS-Urban in Fushun in Liaoning province and in Jinan in Shangdong province respectively, for studies of urban air quality. Finally the conclusions are presented.

Comparison between the Chinese EIA Guidelines for Air Dispersion Modelling and the Advanced Air Dispersion Model ADMS

This paper makes comparisons between Chinese Environmental Impact Assessment (EIA) Guidelines for Air dispersion modelling and the advanced air dispersion model ADMS. Since 2001 the ADMS model has been the first and only foreign model that has been approved by the Appraisal Center for Environment and Engineering (ACEE) to be used in EIA projects in China (http://www.china-eia. com/inden_content/rjrz/ rjrz_ADMS/htm). In the paper the following sections provide brief descriptions of the main features of the Chinese Guidelines for Air Dispersion (Section 2) and ADMS (Section 3); Section 4 provides a comparison of the two modelling methods for some simple cases and conclusions and discussion are given in Section 5.

A Microscale Model for Air Pollutant Dispersion Simulation in Urban Areas： Presentation of the Model and Performance over a Single Building

A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion model to simulate the pollutant concentration through consideration of the influence of urban buildings. Numerical experiments are designed to evaluate the model＇s performance, using CEDVAL （Compilation of Experimental Data for Validation of Microscale Disper- sion Models） wind tunnel experiment data, including wind fields and air pollutant dispersion around a single building. The results show that the wind model can reproduce the vortexes triggered by urban buildings and the dispersion model simulates the pollutant concentration around buildings well. Typically, the simulation errors come from the determination of the key zones around a building or building cluster. This model has the potential for multiple applications; for example, the prediction of air pollutant dispersion and the evaluation of environmental impacts in emergency situations; urban planning scenarios; and the assessment of microscale air quality in urban areas.

Unified Data Model of Urban Air Pollution Dispersion and 3D Spatial City Model:Groundwork Assessment towards Sustainable Urban Development for Malaysia

Understanding the behavior of urban air pollution is important en route for sustainable urban development (SUD). Malaysia is on its mission to be a developed country by year 2020 comprehends dealing with air pollution is one of the indicators headed towards it. At present monitoring and managing air pollution in urban areas encompasses sophisticated air quality modeling and data acquisition. However, rapid developments in major cities cause difficulties in acquiring the city geometries. The existing method in acquiring city geometries data via ground or space measurement inspection such as field survey, photogrammetry, laser scanning, remote sensing or using architectural plans appears not to be practical because of its cost and efforts. Moreover, air monitoring stations deployed are intended for regional to global scale model whereby it is not accurate for urban areas with typical resolution of less than 2 km. Furthermore in urban areas, the pollutant dispersion movements are trapped between buildings initiating it to move vertically causing visualization complications which imply the limitations of existing visualization scheme that is based on two-dimensional (2D) framework. Therefore this paper aims is to perform groundwork assessment and discuss on the current scenario in Malaysia in the aspect of current policies towards SUD, air quality monitoring stations, scale model and detail discussion on air pollution dispersion model used called the Operational Street Pollution Model (OSPM). This research proposed the implementation of three-dimensional (3D) spatial city model as a new physical data input for OSPM. The five Level of Details (LOD) of 3D spatial city model shows the scale applicability for the dispersion model implementtation. Subsequently 3D spatial city model data commonly available on the web, by having a unified data model shows the advantages in easy data acquisition, 3D visualization of air pollution dispersion and improves visual analysis of air quality monitoring in urban areas.

Effects of supply air temperature and inlet location on particle dispersion in displacement ventilation rooms

The effects of supply temperature and vertical location of inlet air on particle dispersion in a displacement ventilated （DV） room were numerically modeled with validation by experimental data from the literature. The results indicate that the temperature and vertical location of inlet supply air did not greatly affect the air distribution in the upper parts of a DV room, but could significantly influence the airflow pattern in the lower parts of the room, thus affecting the indoor air quality with contaminant sources located at the lower level, such as particles from working activities in an office. The numerical results also show that the inlet location would slightly influence the relative ventilation efficiency for the same air supply volume, but particle concentration in the breathing zone would be slightly lower with a low horizontal wall slot than a rectangular diffuser. Comparison of the results for two different supply temperatures in a DV room shows that, although lower supply temperature means less incoming air volume, since the indoor flow is mainly driven by buoyancy, lower supply temperature air could more efficiently remove passive sources （such as particles released from work activities in an office）. However, in the breathing zone it gives higher concentration as compared to higher supply air temperature. To obtain good indoor air quality, low supply air temperature should be avoided because concentration in the breathing zone has a stronger and more direct impact on human health.

Numerical investigation on fire-induced indoor and outdoor air pollutant dispersion in an idealized urban street canyon

Fire-induced pollutant dispersion under the influence of buoyancy in urban street canyons has attracted wide attention given its adverse impact on human health.This study analyzes the influences of fire source location and crossflowing wind(perpendicular to the canyon centerline)on indoor and outdoor air pollutant dispersion in an idealized urban street canyon by employing large eddy simulation.Three fire scenarios are defined according to the transverse location of the fire source:near the windward building(scenario 1),in the middle of the canyon(scenario 2),and near the leeward building(scenario 3).Results show that a re-entrainment phenomenon appears when the wind velocity reaches a critical value in scenarios 1 and 2,but it doesn't occur in scenario 3.Fire source location significantly influences the critical re-entrainment velocity.The critical velocity in scenario 1 is approximate 1.2-1.5 m/s larger than that in scenario 2.When the heat release rate is large,the critical Fr numbers are less sensitive to changes in HRR,and remain approximately constant with values of 0.47(scenario 1)and 0.37(scenario 2).When the wind velocity is large,more compartments are expected to be affected in the upper floors in all of the three scenarios,and smoke is distributed in an inverted triangle within the buildings.The indoor/outdoor temperature and pollutant concentrations are also analyzed.Our findings can provide valuable information for both human and property safety in relation to urban street canyons and their surrounding buildings.

Improving modeling of low-altitude particulate matter emission and dispersion:A cotton gin case study

Monitoring and modeling of airborne particulate matter(PM)from low-altitude sources is becoming an important regulatory target as the adverse health consequences of PM become better understood.However,application of models not specifically designed for simulation of PM from low-altitude emissions may bias predictions.To address this problem,we describe the modification and validation of an air dispersion model for the simulation of lowaltitude PM dispersion from a typical cotton ginning facility.We found that the regulatory recommended model(AERMOD)overestimated pollutant concentrations by factors of 64.7,6.97 and 7.44 on average for PM 2.5,PM 10,and TSP,respectively.Pollutant concentrations were negatively correlated with height(p<0.05),distance from source(p<0.05)and standard deviation of wind direction(p<0.001),and positively correlated with average wind speed(p<0.001).Based on these results,we developed dispersion correction factors for AERMOD and cross-validated the revised model against independent observations,reducing overestimation factors to 3.75,1.52 and 1.44 for PM 2.5,PM 10 and TSP,respectively.Further reductions in model error may be obtained from use of additional observations and refinement of dispersive correction factors.More generally,the correction permits the validated adjustment and application of pre-existing models for risk assessment and development of remediation techniques.The same approach may also be applied to improve simulations of other air pollutants and environmental conditions of concern.

Dispersion modeling and health risk assessment of dioxin emissions from a municipal solid waste incinerator in Hangzhou,China

The emission of dioxins from municipal solid waste incinerators(MSWIs) has become a widespread concern.The effect of meteorological parameters(wind speed,atmospheric stability and mixing height) on the hourly ground level concentration(GLC) of dioxins was estimated using air dispersion models.Moreover,the health risks of dioxin exposure were evaluated for children and adults using the Nouwen equation.The total environmental exposure via air inhalation and food ingestion was calculated,based on linear fit equations.The results indicate that potentially severe pollution from dioxins occurs at a wind speed of 1.5 m/s with atmospheric stability class F.In addition,local residents in the study area are exposed to severe weather conditions most of the time,and the risk exposures for children are far higher than those for adults.The total exposure for children far exceeds the tolerable daily intake of dioxin recommended by the World Health Organization(WHO) of 1-4 pg TEQ/(kg·d) under severe weather conditions.Results from modeling calculations of health risk assessment were consistent with dioxin levels obtained during actual monitoring of emissions.