Showing papers in "International Journal of Environment and Pollution in 2015"

Inverse modelling methods for identifying unknown releases in emergency scenarios: an overview

Abstract: The fast and accurate identification of unknown releases helps in an effective implementation of emergency preparedness (including plume exposure assessment) and public safety programs. The identification is based on networking of several receptors, limited a priori information, remotely measured concentrations, use of dispersion model, site description, meteorology, etc. This is considered as an ill-posed inverse problem. An overview of recently proposed/utilised inversion techniques is discussed with their various applications ranging from local scale to regional scale, limitations and inter-comparisons. The studies addressing identification of multiple-point releases are also included. In addition, the current issues, limitations and future scope associated with the inverse modelling are mentioned.

The effects of trees on micrometeorology in a real street canyon: Consequences for local air quality

Abstract: This study analyses the effects of trees on local meteorology of a Mediterranean City (Lecce, IT) using field measurements and computational fluid dynamics simulations. Measurements were collected for 51 days in a street canyon with trees to cover different meteorological and foliage conditions. Building facades and ground temperatures were estimated from infrared images, flow and turbulence measured by ultrasonic anemometers. In the case of approaching wind parallel to the street axis, trees induce large wind direction fluctuations below tree crowns and velocities up to about 80% lower than those at roof top. This, combined with the obstruction by tree crown, lead to lower ventilation in the bottom part of the street, especially during nocturnal hours, and to in-canyon volume-averaged pollutant concentration about 20% larger than in the tree-free case. Ignoring trapping effects of trees, as typically done in many air quality models, may lead to underestimation of ground level concentrations.

Hints to discriminate the choice of wet deposition models applied to an accidental radioactive release

Abstract: In nuclear emergency management, wet deposition modelling is of crucial importance for correctly evaluating soil contamination after an atmospheric release. Wet deposition is generally divided into two main processes: in-cloud scavenging (rainout) and below-cloud scavenging (washout). The large number of schemes proposed in the literature for both processes reflects the uncertainties in our current understanding of these phenomena. There is presently no scientific consensus to discriminate between the two processes. In order to improve our understanding of the magnitude of modelling uncertainties, a comprehensive sensitivity analysis was performed by focusing on representation of wet deposition fluxes. A large number of model configurations involving different deposition schemes and modelling options were evaluated by comparison with available observations of soil contamination. The objective is to establish a priority rank order of wet deposition schemes for soil contamination modelling.

Application of WRF-Chem to Forecasting PM10 Concentration over Poland

Abstract: The meteorological and chemical transport model WRF-Chem was implemented to forecast PM10 concentrations over Poland. WRF-Chem version 3.5 was configured with three one-way nested domains using the GFS meteorological data and the TNO MACC II emissions. The 48 hour forecasts were run for each day of the winter and summer period of 2014 and there is only a small decrease in model performance for winter with respect to forecast lead time. The model in general captures the variability in observed PM10 concentrations for most of the stations. However, for some locations and specific episodes, the model performance is poor and the results cannot yet be used by official authorities. We argue that a higher resolution sector-based emission data will be helpful for this analysis in connection with a focus on planetary boundary layer processes in WRF-Chem and their impact on the initial distribution of emissions on both time and space.

Monitoring and analysis of PM10 concentration at Delhi Metro construction sites

Abstract: Among all critical air pollutants, particulate matter pollution (PM10) is being awarded greater significance over the past decade. Along with vehicular traffic and meteorological phenomenon, construction works are the major source for release of PM10 in the atmosphere. It is a major source for acute, chronic and respiratory health problems. It produces short term as well as long term health problems in day-to-day lifestyle. This study aims to collect real time particulate matter data from metro construction sites to understand the gravity of the particulate matter pollution due to metro construction works. EPAM HAZ 5000 dust sampler is used to conduct the field studies and record the particulate matter (PM10) levels at Badli, Mayapuri and Najafhgarh metro construction sites of Delhi, India. The results report alarmingly high levels of particulate matter pollution, i.e., 245 ppm (during peak hours), 222 ppm (during peak hours) at Najafgarh and Mayapuri metro construction sites respectively, with time weighted average of PM10 concentration exceeding the national ambient air quality standards (24 hr) of 100 µg/m3.

Comparison of the WRF and Sodar derived planetary boundary layer height

Abstract: In this work, we compare the planetary boundary layer (PBL) height, calculated with the weather research and forecasting (WRF) model, with the measurements from an acoustic remote sounding system (Sodar) gathered at Wrocaw, SW Poland. The comparison was made for 15-30 November 2011. During this period, very high concentrations of PM2.5 were observed in SW Poland. For nine days, the 24-hour average PM2.5 concentrations reached the level 'unhealthy for sensitive groups' and for two days the 'unhealthy' level according to the air quality index. Four simulations were run with different PBL schemes for the innermost domain. The tested PBL schemes were: Yonsei University (sim1), Mellor-Yamada Nakanishi and Niino Level 3 (sim2), Asymmetric Convective Model 2 (sim3) and Bougeault-Lacarrere (sim4). The results show that all the schemes tested overestimate the PBL height, with the largest mean absolute errors for sim1 and sim2 (215 and 225 m, respectively). The mean error is significantly smaller for sim3 and sim4 (109 and 72 m, respectively). The agreement between the WRF and Sodar PBLH has a diurnal pattern and changes with the Pasquill stability classes. The overestimation of the PBL height might lead to the underestimation of air pollutant concentrations modelled with the air quality models.

Assessment of port-related air quality impacts: geographic analysis of population

Abstract: Increased global trade has led to greater transportation by rail, road and ships to move cargo. Based upon multiple near-road and near-source monitoring studies, the busy roadways and large emission sources at ports may impact local air quality within several hundred metres of the ports. Health effects have been associated with near-road exposures and proximity to large emission sources, so characterising emission sources is important for understanding potential health effects. To address this need, we have developed a new community-scale tool called C-PORT to model emissions related to all port-area activities and predict concentrations of multiple criteria and hazardous air pollutants at fine spatial scales in the near-source environment. We present a geographical information system analysis of areas surrounding five US ports (Ports of New York and New Jersey, Virginia, Savannah, Miami, and Houston) to determine potential sources of concern related to freight transport and demographics of the near-source population that could be affected.

On the effect of the aspect ratio on flow and turbulence over a two-dimensional street canyon

Abstract: This paper presents a water-channel simulation of flow and turbulence in the urban boundary layer. The goal is to assess the role played by the aspect ratio (AR) of the street canyon, assumed as an archetype for more complex and realistic urban fabrics. The physical model consists of a series of two-dimensional obstacles used to mimic a regular array of buildings. Velocity measurements are performed using image analysis. Results show a dependence of the mean velocity and turbulence parameters on AR. Attention is particularly focused on the turbulent kinetic energy and its production-advection-dissipation mechanisms that occur in the urban canopy.

Analysis and modelling of turbulent fluxes in two different ecosystems in Argentina

Abstract: Turbulence data measured with fast response instruments at two sites with distinct conditions were available The ability of a mesoscale model in the simulation of turbulent fluxes and boundary layer height was assessed in case studies covering periods in the Southern Hemisphere summer and winter The energy apportionment at both locations was properly reproduced In summer, at the site with native forest, the sensible heat flux was well estimated and the latent heat flux was underestimated At the other site (commercial plantation) the sensible heat flux was properly represented and the latent heat flux was slightly overestimated In winter, the best results were obtained at the implanted forest site The performance of the model at the native forest site was very satisfactory when homogeneous initial soil moisture was considered A model intercomparison between the boundary layer height obtained with an analytical model and the mesoscale model showed the influence of data and methodologies used in the two approaches

Total oxidation of toluene over gold supported on mesoporous ferrisilicates materials

Abstract: Mesoporous ferrisilicates MFS-n (n = Si /Fe) with different Si/Fe molar ratio (Si/Fe = 20, 135) were synthesised by the assembly of Fe MFI nanoclusters with triblock copolymers in strongly acidic media. Au/MFS-n catalysts were prepared by deposition-precipitation with urea (DPU) with a loading of gold of 1 wt%. They were characterised by various techniques including XRD, BET, FT-IR spectroscopy; diffuse reflectance UV-vis (DRUV-vis), TPR. Total oxidation of toluene was investigated on MFS-n and Au/MFS-n. The catalytic activity of MFS-n materials for total toluene oxidation is considerably enhanced as the iron content increases. The presence of gold improves the catalytic activity of MFS-n towards the combustion of toluene, the extent of this effect depending on the Si/Fe molar ratio. The catalysts are totally selective for CO2 and H2O.

A source term estimation method for a nuclear accident using atmospheric dispersion models

Abstract: The objective of this study is to develop an operational source term estimation (STE) method applicable for a nuclear accident like the incident that occurred at the Fukushima Dai-ichi nuclear power station in 2011 The new STE method presented here is based on data from atmospheric dispersion models and short-range observational data around the nuclear power plants The accuracy of this method is validated with data from a wind tunnel study that involved a tracer gas release from a scaled model experiment at Tokai Daini nuclear power station in Japan We then use the methodology developed and validated through the effort described in this manuscript to estimate the release rate of radioactive material from the Fukushima Dai-ichi nuclear power station

The Uncertainty in Modelled Air Concentrations of NOx Due to Choice of Emission Inventory

Abstract: Emission data, together with meteorology, is the most important input to air quality models. In this work we compare two simulations, performed with the fine resolution atmospheric multi-pollutant exchange (FRAME) model. In the first model run, we use an emission inventory prepared for Poland by downscaling the national total emissions to a 5 km × 5 km resolution grid. For the second model run, we replace the NOx road transport emission with the TNO-MACC II emission inventory available for the entire Europe. The grid mesh of both emission inventories was unified for this work to a 5 km × 5 km resolution, as required by the FRAME model. The FRAME model is run for the year 2008 and compared with the NOx measurements. Both inventories are in close spatial agreement, with a grid to grid correlation coefficient of 0.75. The FRAME model run with TNO-MACC II emission inventory shows better agreement with NOx measurements gathered at 106 stations if the mean bias is considered. For the model run with TNO-MACC II inventory, bias is −0.7 μg m³, and the RMSE is 8.19 μg m³. The bias for the FRAME model run with the national road transport emission inventory is −3.10 μg m³ and the RMSE 7.97 μg m³.

The possibilities of restoring the enzymatic balance of soil contaminated with cadmium

Abstract: The effectiveness of four substances, including two innovative products - basalt meal and algae extract, and two conventional soil improvers - barley straw and compost, was evaluated in this study. The activities of soil enzymes (dehydrogenases, urease, acid phosphatase, alkaline phosphatase and catalase) in response to increasing Cd2+ doses were monitored. Enzymatic activity levels were used to calculate indicators of soil resistance (RS) and soil resilience (RL). The evaluated enzymes were classified in the following order based on their sensitivity to soil pollution with Cd2+: dehydrogenases > urease > alkaline phosphatase > acid phosphatase > catalase. Barley straw was most effective in mitigating the adverse impact of Cd2+ on the biochemical properties of soil, whereas algae extract and compost were less effective soil amendments. Compost neutralised the inhibitory effect of Cd2+ on enzymatic activity, but it significantly enhanced the analysed metal's negative impact on oat yield. Basalt meal was not an effective soil improver.

Public participation in environmental permitting: the Finnish approach and its effects

Abstract: In response to global environmental issues, environmental governance has received increased attention. Environmental permitting as a key instrument has contributed to mitigating industrial environmental impacts, facilitating its compliance with environmental requirements and promoting technological innovation. Environmental permitting requires transparent and broad public participation, since public engagement in environmental issues is closely correlated to the development of civil society. Finland, as a country successful in the area of environmental protection, has the advanced mechanism of public participation in environmental permitting employed in all sectors of society. However, current literature indicates fragmented information available about the Finnish approach and the effects of public participation in environmental permitting. The exploratory study firstly discloses the Finnish integrated environmental permit systems. Subsequently, this paper illustrates Finnish public participation practices including the opportunities for this activity, its communication patterns, positive effects, as well as its side effects. Finally, concluding remarks are put forward.

Comparison between different dynamical downscaling methods using WRF-Chem for urban applications: Madrid case study

Abstract: The European Centre for Medium-Range Weather Forecasts is used to provide boundary conditions for the mesoscale model WRF-Chem that has been run over Europe with 23 km spatial resolution. We have used a full one-way nesting approach to produce simulations centred over the city of Madrid (Spain) with 4.6 km spatial resolution, 0.92 km spatial resolution and 0.184 km spatial resolution. In last level, we have run the CMAQ (full chemistry) model to produce chemical pollution data. This is called the control reference simulation. The simplified and faster downscaling procedure used in this experiment is the CALMET-CMAQL (linear chemistry) model. Both downscaling techniques are compared using meteorological and air pollution monitoring station. The comparison between both downscaling techniques shows that the CALMET-CMAQL model is much faster and computationally cheap; the results are good enough to consider this tool for climate purposes.

Temporal trends of spatial correlation within the PM10 time series of the AirBase ambient air quality database

Abstract: We analyse the temporal variations which can be observed within time series of variogram parameters (nugget, sill and range) of daily air quality data (PM10) over a ten years time frame. Datasets have been obtained from previous geostatistical analysis of country wide datasets from the AirBase ambient air quality database. Applying the Kolmogorov-Zurbenko filtering method, the time series are first decomposed into their short-, mid-, and long-term components. Based on this, we then evaluate the magnitude of the individual spectral signal contributions. Furthermore, the significance of a long term trend component is investigated by a block-bootstrap-based approach combined with linear regression. It is discussed if within these datasets the times series of nugget variance can provide information about the evolution of the measurement uncertainty of the related air pollutant, whereas the sill and the range parameters could contain information about the spatial representativeness of the monitoring stations.

How does the use of biodiesel affect urban air quality

Abstract: This study aims to assess the influence of the use of a B20 fuel by road transports on urban air quality. For this purpose emission scenarios were designed and their impacts on air quality assessed using the WRF-EURAD modelling system applied over the Porto urban area. The scenarios consider emissions of CO, NOx, NMVOC, PM10, PM2.5, formaldehyde, acetaldehyde, acrolein and benzene from the use of pure diesel (reference scenario) and the use of a diesel blended with 20%(v/v) of biodiesel (B20 scenario). The results reveal that the use of B20 fuels improves the air quality over the Porto urban area, reducing the concentrations of most of the studied pollutants, with the exception of NO2. However, the concentrations vary in a small amount. Despite carbonyl compound emissions not being considered as individual input for the WRF-EURAD numerical modelling system, the equivalent ozone production estimated from the compound's emission variations indicate that the use of B20 can increase the O3 concentrations over the Porto urban area.

Spatial distribution of phosphorus in sediments at the Caohai lakeshore area

Abstract: This study investigated the distribution and changes in phosphorus (P) forms within surface and column sediments collected from the lakeshore area of Caohai, Dianchi Lake. Results showed that the sediments of the Caohai lakeshore area were high in total phosphorus (TP), with a maximum value of 2,452 mg•kg−1. The variation in P content within sediments from various regions was large. Inorganic phosphorus (IP) was the major part of TP. The Fe, Al, and Mn oxide and hydroxide (Fe/Al-P) content was higher than the calcium bound P content. This will facilitate the release of P into the water.

Perfluorooctane sulfonate and perfluorooctanoic acid in Qiantang River waters of China

Abstract: Recently, there has been increasing concern about perfluorinated compounds, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). To characterise the seasonal change of PFOS and PFOA in the Qiantang River waters of China, 48 water samples from March to September in 2013 were collected and analysed in this study. The concentrations of PFOS and PFOA were n.d-1.186 ng/L and from 5.35-137.5 ng/L, respectively. PFOS has been observed at a low concentration in these samples, while PFOA was detected in 100% of the samples with higher PFOA concentrations. PFOA concentrations were far higher than those of PFOS in all the samples, which were influenced by the inflows of the chemicals from a lot of the textile dyeing industry along the south bank of the river. Although the PFOS and PFOA concentrations in Qiantang River water samples did not exceed this provisional health advisory level (limit) established by the United States Environmental Protection Agency for PFOS and PFOA in drinking waters of 200 ng

Application of chemical dispersion model during a high ozone episode in South-West Poland

Abstract: In this study, the Weather Research and Forecasting model with chemistry (WRF-Chem v3.5) is applied to the area of Poland, for a period of 03.07-03.08.2006, when high concentrations of ground level ozone were observed. The meteorological and chemistry simulations were initiated with the ERA-Interim reanalysis and the TNO MACC-II emissions database. Simulations were performed for three one-way nested domains. The results from the innermost domain were examined and compared to measurements of ozone concentrations and meteorological variables. The modelled results show a general underestimation of measured ozone concentrations. For urban and suburban sites it is significantly higher during day time. Domain-wide estimations of temperature were also underestimated, and relative humidity and wind speed were overpredicted. The results may be further improved by adjusting physical parameterisations and including a more detailed emission input data into the model.

Adsorption of lead ions in contaminated water using commercial hydrophilic silica nanoparticles

Abstract: The adsorption of lead ions from simulated industrial wastewater using hydrophilic commercial silica nanoparticles (Aerosil A130VS) is reported. These results were compared with those obtained using sol-gel silica nanoparticles prepared in our laboratory. Hydrated commercial silica nanoparticles have, on their surface, silanol groups (≡Si-OH) that are appropriated for the adsorption process. The commercial particles are dense because they are produced by a pyrogenic process. The absence of pores means a smaller internal surface area and, consequently, a smaller number of silanol groups available for adsorption; as compared with the highly porous sol-gel silica nanoparticles. This effect is partially compensated by the small particle size that can be obtained from these commercial particles. Different concentrations of lead ions in aqueous solution were added to a suspension of commercial particles until the critical flocculation concentration was reached. The flocculation kinetic was obtained using dynamic light scattering and the amount of adsorbed lead ions using atomic absorption. The lead concentration was reduced from 65.9 ppm to 0.2 ppm using Aerosil A130VS.

Mean Annual Population Exposure to Atmospheric Particulate Matter in Poland

Abstract: The main aim of this study is to provide information about the number of people exposed to different levels of the total mean PM10 and PM2.5 concentration and to calculate population weighted concentration both as a total value (for PM10 and PM2.5) and for individual chemical species. The study area is Poland for the year 2007. The concentration of particulate matters was provided with the fine resolution atmospheric multi-pollutant exchange (FRAME) model with a 5 km × 5 km spatial resolution. The FRAME simulations included anthropogenic emissions, as well as sea salt aerosol and wind blown dust. We have found that the entire population is exposed to PM2.5 concentration above 5.0 μg m−3, which is suggested to have an adverse impact on human health. Primary particulate matter has the highest contribution in total PM10and PM2.5 population weighted concentration and is followed by secondary inorganic aerosols.

The FMI emission inventory and source-receptor calculations across Finland's eastern border

Abstract: The source-receptor calculations of European monitoring and evaluation program (EMEP) between Finland and Russia have been discussed in the Finnish public media in autumn 2013 after the Russian environmental organisation Green Patrol accused Western countries of polluting the Kola Peninsula. The air pollution fluxes between Russia and Nordic countries calculated with the EMEP western centre are based on emission data, which in North-Western Russia are significantly lower than in other European emission inventories. In this paper, North-Western Russian air emissions and the pollution fluxes between Finland, Russia and the Baltic Sea are discussed.

Experiences in dispersion modelling in the development of an air quality management system in Krakow

Abstract: Krakow is one of the most polluted cities in Poland and in Europe. As a result of ten years of collecting data, tools and knowledge have been developed and the participation of citizens and their support has been built, which has led to the implementation of a difficult and hopefully effective action plan for Krakow. The study shows how the results of dispersion modelling have influenced the development of air quality management methods in the city of Krakow within the period of 2004-2013. The key findings on particulate matter origins are presented as well as past and current air quality improvement tools.

Lagrangian micromixing modelling of reactive scalar statistics: scalar mixing layer in decaying grid turbulence

Abstract: A Lagrangian micro-mixing numerical model estimates the concentration statistics of reactive pollutants (NO, O3 and NO2) of a scalar mixing layer in decaying grid turbulence. A stochastic macro-mixing scheme computes the fluid particle trajectories, which describe the turbulent flow (Lagrangian turbulence), whereas the micro-mixing scheme interaction by the exchange with the conditional mean (IECM), implementing a new formulation for the mixing time, represents the dissipation of concentration turbulent fluctuations due to molecular diffusion. The non-homogeneous reaction-dominated limit (NHRDL) of the conserved scalar theory simulates chemical reactions. The numerical model integrates these three schemes and is validated by comparison with experimental and direct numerical simulation (DNS) data, whereas inter-comparisons with other numerical models are also reported. The study focuses on the reliability of Lagrangian stochastic models in representing micro-scale pollutant dispersion (air quality) and the importance of representing chemical reactions depending on instantaneous concentrations rather than their means.

Empirical background model of total ozone density over Bulgaria

Abstract: A detailed analysis of the variations of the stratospheric and mesospheric ozone over Bulgaria, in the period 1996 to 2012, is presented in the article on the basis of ground and satellite measurements of the total ozone column (TOC). The dynamics of the most important components has been studied. Their mean values for the period and the existing long-term trends have been found. The time evolution of the most basic components of the seasonal course has been studied, including the existing long-term trends and their relations to the stratospheric temperature and quasi-biennial oscillation. Based on these studies and analyses, an empirical model for a daily forecast of TOC over Bulgaria has been created. The main aim of the model is monitoring of the ozone layer and, respectively, the biologically harmful ultraviolet radiation of the sun related to it which has an effect on human health and life.