Evergreen oak leaves as natural monitor in environmental pollution

Evergreen oak was chosen as a possible biological monitor of environmental pollution. It was shown that there is a direct relationship between the concentration of elements in leaves and the presence of pollution sources, i.e. the density of vehicular traffic.     

Polycyclic aromatic sulfur heterocycles as information carriers in environmental studies

Polycyclic aromatic hydrocarbons (PAHs) play a huge role in environmental analytical chemistry, both as pollutants and as markers for many processes. On the other hand, polycyclic aromatic sulfur heterocycles (PASHs; heterocyclic compounds related to PAHs) have been studied far less intensely, but such studies may lead to a great deal of information not available through the study of PAHs. Here we discuss analytical aspects of PASHs in environmental matrices and their use as information carriers. Since PASHs accompany PAHs in sampling and work-up, it is not necessary to expend much extra analytical effort in order to analyze them. This work reviews how they can provide information on diverse processes such as petroleum, industrial and vehicular pollution, and sources of air and marine pollution.     

Botanical environmental monitors for zinc pollution resulting from vehicular traffic

Botanical samples were used as monitors for zinc pollution resulting from vehicular traffic. Euphorbia terracina and Calotropis procera were the botanical monitors used in this work. Zinc concentrations were reported alongside a motorway stretch of 50 km. Variations in concentration with respect to the perpendicular distance from the roadside were also reported. The effect of wind turbulence and the wind direction on the concentrations is discussed. In addition, differences between open areas and confined areas with respect to the elemental uptake were also discussed. INAA, using reactor neutrons, was employed for the determination of Zn concentrations in the samples.     

Biomonitoring of the atmospheric pollution using lichens in the metropolitan area of São Paulo city,Brazil

The atmospheric pollution of São Paulo city is a serious problem due to the expansion of industrial area, increasing number of vehicles and population density. This work presents results obtained in the analysis of lichens collected in different sites of São Paulo city and in non-polluted areas of Atlantic Forest. Concentrations of twenty elements were determined in Canoparmelia texana species and comparisons were made between the results obtained in lichens from different sites. High concentrations of the elements As, Ba, Cd, Co, Cr, Fe, La, Mn, Sb and Zn were found for samples collected in sites located near industries and petrochemical plant. Br and Sb concentrations were also high in lichens from sites affected by vehicular emissions.     

The use of Tillandsia usneoides L. as bioindicator of air pollution in São Paulo, Brazil

Epiphytic bromeliadTillandsia usneoides was used as a biomonitor of metal atmospheric pollution in the city of São Paulo, Brazil. The samples were collected from an unpolluted area and were exposed for 8 weeks in 10 sites of the city and in a control site. The data obtained showed that the control site presented lower concentration for most elements analyzed and the highest concentrations of Na, Cl, Br, K. The highest concentrations of Zn, Cu and V were observed in stations submitted to industrial and vehicular sources. The results obtained for rare earth elements, Al, Fe, Mg, Mn, Rb and Sc indicate mineral dust origin. The elements Ba, As and Sb presented higher values in stations near streets with heavy traffic.     

Air quality study of Islamabad: preliminary results

Over a 1,000 pairs of coarse and fine filters were collected using Gent samplers and polycarbonate filters from three sites in Islamabad from the period 1998 to 2010. The black carbon in these samples was determined by reflectance measurement while their elemental composition were determined using the techniques of instrumental neutron activation analysis, ion beam analysis and X-ray fluorescence spectrometry. Islamabad is a well planned and relatively small city as compared to Lahore or Karachi therefore its air quality is better than the air quality of other major Pakistani cities. It was found that the new air quality standards being implemented by the Pakistani government on the 1st of January 2012 may not be attained even in Islamabad without the implementation of control and remedial measures. An overview of the elemental data obtained and calculation of enrichment factors shows that the particles in Islamabad originate from re-suspended soil, vehicular emissions and coal combustion. However further work is required for identification of pollution sources and their origin.     

Metals and semi-metals in street soils of São Paulo city,Brazil

São Paulo is the largest city in Brazil and South America with about 20 million inhabitants in the metropolitan area, more than nine million motor vehicles and intense industrial activity, which are responsible for increasing pollution in the region. Nevertheless, little is known concerning metal and semi-metal content in the soils of this metropolitan region. This type of information could be extremely useful as a fingerprint of environmental pollution. The present study determined the elements As, Ba, Co, Cr, Sb, and Zn concentrations in soils adjacent to avenues of highly dense traffic in São Paulo city to assess their levels and possible sources. The analytical technique employed was Instrumental neutron activation analysis. The results showed, except for Co, concentration levels higher than the reference values for soils of São Paulo, according to the Environmental Protection Agency of the State of São Paulo guidelines. When compared to similar studies in other cities around the world, São Paulo soils presented higher levels, probably due to its high density traffic and industrial activity. The concentrations obtained for As and Cr indicate anthropogenic origin. The high levels of the traffic-related elements Ba, Sb, and Zn in soils nearby high density traffic avenues indicate they may originate from vehicular exhausts.     

Neutron activation analysis of automobile exhaust pollutants

An approximation of the distribution of lead particulate from vehicular exhausts is given. A neutron activation analysis study has shown that there is an extremely detailed pattern of the effluent from vehicular highway traffic.     

Benzene and Toluene Levels Measured with DOAS During Vehicular Restrictions in Beijing

Measurements of atmospheric benzene and toluene were carried out continuously using dif-ferential optical absorption spectroscopy from August 7 to August 28 in Beijing during the period of vehicular restrictions. The correlations between traffic flows and totals of benzene and toluene were studied during the period of vehicular traffic restrictions from August 17 to August 20 and non-traffic restrictions on August 16 and August 21. The correlation coef-ficient was 0.8 between benzene and toluene. And the calculated daily mean value ratios of benzene to toluene were 0.43-0.50. During the period of vehicular restrictions, traffic flows were reduced about 11.8% and the levels of benzene and toluene were reduced by 11.4% and 12.8%, respectively. The vehicle emissions were recognized as the major sources for atmospheric benzene and toluene in Beijing.     

Nonpolar organic compounds in fine particles: quantification by thermal desorption–GC/MS and evidence for their significant oxidation in ambient aerosols in Hong Kong

Nonpolar organic compounds (NPOCs) in ambient particulate matter (PM) commonly include n-alkanes, branched alkanes, hopanes and steranes, and polycyclic aromatic hydrocarbons (PAHs). The recent development of thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) has greatly reduced time and labor in their quantification by eliminating the laborious solvent extraction and sample concentration steps in the traditional approach that relies on solvent extraction. The simplicity of the TD-GCMS methods has afforded us concentration data of NPOCs in more than 90 aerosol samples in two aerosol field studies and 20 vehicular emissions-dominated source samples in Hong Kong over the past few years. In this work, we examine the interspecies relationships between select NPOCs and their concentration ratios to elemental carbon (EC) among the ambient samples and among the source samples. Our analysis indicates that hopanes were mainly from vehicular emissions and they were significantly oxidized in ambient PM. The hopane/EC ratio in ambient samples was on average less than half of the ratio in vehicular emissions-dominated source samples. This highlights the necessity in considering oxidation loss in applying organic tracer data in source apportionment studies. Select PAH/EC ratio–ratio plots reveal that PAHs had diverse sources and vehicular emissions were unlikely a dominant source for PAHs in Hong Kong. Biomass burning and other regional sources likely dominated ambient PAHs in Hong Kong.     

Application of receptor models to airborne particulate matter

The human activities in their various aspects cause a change in the natural air quality. This change results more marked in very populated and in high industrialized areas. Some pollutants emitted are typical of a particular activity. Each source of pollution is identified by its profile in the composition of the emissions in the environment. Multivariate receptor models can be used in order to apportion pollutants to the different sources assessing the contribution of each source to the total pollution.This paper deals with the application of Absolute Principal Component Scores (APCS) receptor model to data obtained from the automatic network of air quality monitoring in the city of Bari (South Italy). The parameters monitored by automatic networks, as bihourly values, are PM₁₀, NO_x, CO, Benzene, Toluene, Xilene. The data shown in this paper concerning 1 month almost of sampling in different monitoring stations of Bari Municipality during the period of time from January 2005 to April 2006. Moreover preliminary results obtained applying the APCS model to daily PM_2.5 samples collected during SITECOS PRIN project are shown. The results concerning data collected in corso Cavour (Bari) during the month of October 2005.The results obtained by APCS receptor model seem to suggest a poor contribution of the “vehicular traffic source” and a relevant contribution of the “secondary particulate source” to particulate matter concentrations.     

Carbon adsorbents as candidate hydrogen fuel storage media for vehicular applications

The prospects of carbon adsorbents as vehicular hydrogen storage media are briefly discussed.     

Influence of vehicular traffic on a major trunk road on rural air quality in UK

Although poor air quality has long been linked to urban areas, it is seemingly apparent that many rural areas have locations where air quality strategy objectives may be threatened in the wake of increasing vehicular traffic. This study examined the contributions of traffic towards air quality status by conducting monthly assessment of rural air quality along the A49 trunk road. The aim is to observe differences in main pollutant concentrations depending on the distance from the road.Monthly data of particulate deposits were monitored at roadsides, 50 m and 100 m distance in proximity to the A49 trunk road over a 22-month period (June 2008–Apr 2010). Direct analysis by SEM-EDS, ICP-MS, PTrak and XRF revealed a seasonal, intra-and inter-site variations and a distance–decay relationship. However, at some locations with increased vehicular activities, this relationship was altered.     

Evaluation of Platanus occidentalis and Pinus sylvestris as bioindicators for lead and cadmium by slurry sampling-electrothermal atomic absorption spectrometry

Two higher plants (Platanus occidentalis and Pinus sylvestris) were used as bioindicators for assessment of contamination by Pb and Cd in an urban and industrialized area. Both toxic metals in plant tissue were determined by transverse-heated electrothermal atomic absorption spectrometry-longitudinal Zeeman background correction combined with automated ultrasonic slurry sampling. Twenty sampling points were established to observe a relationship between metal concentration in plant and traffic density. Screening optimization of variables influencing slurry preparations (sonication time, sonication power, and surfactant concentration) followed a fractional factorial design at 2 levels. No significant effects were observed in the interval of variables studied. Limits of detection of Pb and Cd in the plants were 0.28 and 0.025 microg/g (dry weight), respectively. Metal concentrations in the plants were in the range of 5-51 and 0.05-0.7 microg/g for Pb and Cd, respectively. Factor analysis to data of metal concentration in both plants, extractable metal content in soil, distance to traffic, and traffic density, showed a significant association between features such as concentration of Pb and Cd in leaves of P. occidentalis and traffic density, which accounted for the largest variance. Other features such as extractable metal contents in soil accounted for lesser variance, meaning that soils in the area investigated were less suitable than plants for monitoring metal pollution caused by vehicular traffic.     

Evidence of coal combustion contribution to ambient VOCs during winter in Beijing

Volatile organic compounds(VOCs)play an important role in ozone and secondary organic aerosol(SOA)formation,but VOCs sources during winter are not fully understood.To investigate VOCs sources during winter,mixing ratios of C2–C12 VOCs were measured at an urban site in Beijing from December 29,2011to January 17,2012.Correlation analysis of toluene to benzene and i-pentane to n-pentane suggest that coal combustion could also be an important source for VOCs besides vehicular emissions.Source apportionment results show that coal combustion and vehicular emissions contributed 28%–39%and31%–45%to ambient VOCs during winter,respectively.Backward trajectory analyses demonstrated that contributions from the burning of coal were higher when air masses came from southern regions outside Beijing.Close attention should be paid to VOCs emissions from coal combustion in Beijing city and the vicinity to the South.     

Determination of Platinum Group Elements and Evaluation of Their Traffic-Related Distribution in Italian Urban Environments

Abstract

The platinum (Pt) distribution in urban matrices, soils and dusts was studied in five cities, from north (Padova), central (Rome and Viterbo), and south (Naples and Palermo) Italy, in order to obtain a large set of data concerning pollution from autocatalysts. Quantitative analyses, made by inductively coupled plasma mass-spectroscopy (ICP-MS), show a beginning of Pt enrichment in urban soils, with concentration ranges of 0.1–5.7 ng/g (Padova), 7–19.4 ng/g (Rome), 4.9–20 ng/g (Viterbo), 4.7–14.3 ng/g (Naples), and 0.2–3.9 ng/g (Palermo). These results can be related to vehicular traffic, because the concentrations decrease with the distance from the roads. The high concentrations found in road and tunnel dusts (up to 1177 ng/g) confirm these samples as the major reserve of the particulate matter that is released with the exhaust fumes (which is responsible for the Pt enrichment). Qualitative analyses by laser-ablation-ICP-MS (LA-ICP-MS) were used, in addition, to determine the real presence of the catalyst particles in the urban dusts. The association of the analytical signals of cerium, platinum, and rhodium was used as a fingerprint to distinguish the catalyst particles from the other components of the urban dusts. The scanning electron microscopy (Energy Dispersive Spectrometer-Scanning Electron Microscope; EDS-SEM) qualitative analysis was also used to characterize the morphology of the autocatalyst and its related elemental distribution.     

Correlation study of air pollution and cardio-respiratory diseases through NAA of an atmospheric pollutant biomonitor

In this study neutron activation analysis was applied to analyze lichen samples used as atmospheric pollutant biomonitors in order to verify if there is correlation between air pollution and its effects on the cardio respiratory system. Canoparmelia texana lichenized fungii species was chosen for passive biomonitoring of atmospheric pollutants. The population group selected for this study was adults over 45 years. Lichen samples collected in São Paulo city were cleaned, freeze-dried and ground for the analyses. Aliquots of samples were irradiated at the IEA-R1 nuclear research reactor for short and long periods along with synthetic element standards. The induced gamma activities of the samples and standards were measured using a gamma ray spectrometer with an HPGe detector and the concentrations of As, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Fe, Hf, K, Mg, Mn, Na, Rb, Sb, Sc, Se,Th, V, Zn and lanthanides were determined. For quality control of the results, certified reference materials were analyzed together. Mortality data for the population due to cardio-respiratory diseases were obtained from the database of the Secretariat of Health of the São Paulo Municipality for the years 2005–2009. Results obtained point to vehicular and industrial emissions as the origins of pollutants in São Paulo city. The statistical treatment of Pearson’s correlation applied to the results of lichen element concentrations and mortality rates indicated significant positive correlation for the elements Co, Mn and Zn for adults.     

Li<Superscript><Emphasis Type="Bold">+</Emphasis></Superscript> Transport Mechanism in Oligo(Ethylene Oxide)s Compared to Carbonates

Molecular dynamics simulations have been performed on oligo(ethylene oxide)s of various molecular weights doped with the lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI) in order to explore the mechanism of Li⁺ transport in materials covering the range from liquid electrolytes to prototypes for high molecular weight poly(ethylene oxide)-based polymer electrolytes. Good agreement between MD simulations and experiments is observed for the conductivity of electrolytes as a function of molecular weight. Unlike Li⁺ transport in liquid ethylene carbonate (EC) that comes from approximately equal contributions of vehicular Li⁺ motion (motion together with solvent) and Li⁺ diffusion by solvent exchange, Li⁺ transport in oligoethers was found to occur predominantly by vehicular motion. The slow solvent exchange of Li⁺ in oligo(ethylene oxide)s highlights why high molecular weight amorphous polymer electrolytes with oligo(ethylene oxide)s solvating groups suffer from poor Li⁺ transport. Ion complexation and correlation of cation and anion motion is examined for oligoethers and compared with that in EC.     

Characterization of the solvation and transport of the hydrated proton in the perfluorosulfonic acid membrane nafion

The solvation and transport properties of the sulfonate-hydronium ion pair have been studied in hydrated Nafion through molecular dynamics simulation. Explicit proton and charge delocalization of the excess proton transport, via the Grotthuss hopping mechanism, were treated using the self-consistent multistate empirical valence bond (SCI-MS-EVB) method. The nature of the sulfonate-hydronium ion pair was characterized through analysis of free-energy profiles. It was found that, in general, the excess proton is solvated between two water molecules of a Zundel moiety while in the contact ion pair position, but then it transitions to an Eigen-like configuration in the solvent-separated pair position. Furthermore, the positive charge associated with the excess proton passes between the contact and solvent-separated ion pair positions through the Grotthuss mechanism rather than simple vehicular diffusion. The total proton diffusion was decomposed into vehicular and Grotthuss components and were found to be of the same relative magnitude, but with a strong negative correlation resulting in a smaller overall diffusion. Correlated motions between the ion pair were examined through the distinct portion of the van Hove correlation function, and a characteristic time scale of approximately 425 ps was observed. Additionally, the association of the hydrated proton with the hydrophobic polymer backbone suggests its amphiphile-like behavior (see Acc. Chem. Res. 2006, 39, 143; Phys. Rev. 1954, 95, 249; J. Chem. Phys. 2005, 123, 084309).     

天然气吸附储存的进展

天然气作为绿色替代能源,其吸附储存在移动应用方面至关重要,目前广泛关注的3种吸附储存技术存在着各自的优势和劣势。本文综述了多孔碳质吸附剂、金属有机框架吸附剂和吸附天然气水合物的研究进展,总结了天然气吸附性能的主要影响因素和改进途径,介绍了超临界吸附理论和分子模拟预测的相关工作,比较了3种技术的优劣及相关发展趋势。