EuroBionet: a pan-European biomonitoring network for urban air quality assessment

EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites.     

Effect of air pollution on peri-urban agriculture: a case study

Peri-urban agriculture is vital for the urban populations of many developing countries. Increases in both industrialization and urbanization, and associated air pollution threaten urban food production and its quality. Six hour mean concentrations were monitored for SO(2), NO(2) and O(3) and plant responses were measured in terms of physiological characteristics, pigment, biomass and yield. Parameter reductions in mung bean (Vigna radiata), palak (Beta vulgaris), wheat (Triticum aestivum) and mustard (Brassica compestris) grown within the urban fringes of Varanasi, India correlated directly with the gaseous pollutants levels. The magnitude of response involved all three gaseous pollutants at peri-urban sites; O(3) had more influence at a rural site. The study concluded that air pollution in Varanasi could negatively influence crop yield.     

Atmospheric pollution in an urban environment by tree bark biomonitoring - part II: Sr, Nd and Pb isotopic tracing

The harmful effect of manmade particles on natural processes and human health is documented by a large number of studies showing a positive correlation between particulate matter (PM) concentration and health effects. Diminution of this health risk necessitates among others the precise knowledge of the particle sources, their physical and chemical properties and their dissemination in the environment. Pb isotope ratios have been successfully used during the past decades as tracers of anthropogenic Pb disseminated in the biosphere. Here we show that tree bark biomonitoring with lead (Pb), strontium (Sr) and neodymium (Nd) isotope ratios as tracers allow a thorough analysis of the impacts of industrial and other anthropogenic emissions on the urban environment. This is the first comprehensive multi-isotope tracer study of atmospheric pollution in an urban environment allowing to identify and to integrate the different plume paths of emissions in a digital map system. This innovative approach might become an important tool for environmental management and policy-making processes dealing especially with risks and surveillance of air quality in the urban environment.     

Large-scale biomonitoring of trace element air pollution: local variance, data comparability and its relationships to human health

This paper addresses large-scale biomonitoring surveys on trace element air pollution. It discusses local variances, the comparability of data, obtained over a large geographical area, and the possibilities to discuss findings in the context of human health issues. The local variances are principally considered as basic properties of the survey, associated with local sites, and, together with survey variance, assumed necessary to judge the quality of the survey. Kriging is proposed as a means to get insights into numerical data on local variances: large-volume samples in elemental analysis may be an approach to avoid problems due to subsampling and homogenisation. The data comparability is discussed in terms of geography-related variability in biomonitor vitality: the discussion underlines that the comparability in vitality should procede any further data comparing. Biomonitoring data, reflecting air concentrations and metal deposition, are discussed in terms of relationships with human health issues: one of the main correlation studies to be performed may be the one focusing on relationships with human monitor tissues.     

Tracking historical lead pollution in the coastal area adjacent to the Yangtze River Estuary using lead isotopic compositions

The rapid economic development in the Yangtze River Delta (YRD), China in the last three decades has had a significant impact on the environment of the East China Sea (ECS). Lead isotopic compositions of a ²¹⁰Pb dated sediment core collected from the coastal ECS adjacent to the Yangtze River Estuary were analyzed to track the Pb pollution in the region. The baseline Pb concentration in the coastal ECS sediments before the industrialization in China was 32 μg g⁻¹, and the corresponding ²⁰⁶Pb/²⁰⁷Pb ratio was 1.195. The high-resolution profiles of Pb flux and ²⁰⁶Pb/²⁰⁷Pb ratios had close relationships with the economic development and the history of the use of leaded gasoline in China, and they were clearly different from those of most European countries and United States.     

Estimated long-term outdoor air pollution concentrations in a cohort study

Several recent studies associated long-term exposure to air pollution with increased mortality. An ongoing cohort study, the Netherlands Cohort Study on Diet and Cancer (NLCS), was used to study the association between long-term exposure to traffic-related air pollution and mortality. Following on a previous exposure assessment study in the NLCS, we improved the exposure assessment methods.Long-term exposure to nitrogen dioxide (NO₂), nitrogen oxide (NO), black smoke (BS), and sulphur dioxide (SO₂) was estimated. Exposure at each home address (N=21 868) was considered as a function of a regional, an urban and a local component. The regional component was estimated using inverse distance weighed interpolation of measurement data from regional background sites in a national monitoring network. Regression models with urban concentrations as dependent variables, and number of inhabitants in different buffers and land use variables, derived with a Geographic Information System (GIS), as predictor variables were used to estimate the urban component. The local component was assessed using a GIS and a digital road network with linked traffic intensities. Traffic intensity on the nearest road and on the nearest major road, and the sum of traffic intensity in a buffer of 100 m around each home address were assessed. Further, a quantitative estimate of the local component was estimated.The regression models to estimate the urban component explained 67%, 46%, 49% and 35% of the variances of NO₂, NO, BS, and SO₂ concentrations, respectively. Overall regression models which incorporated the regional, urban and local component explained 84%, 44%, 59% and 56% of the variability in concentrations for NO₂, NO, BS and SO₂, respectively.We were able to develop an exposure assessment model using GIS methods and traffic intensities that explained a large part of the variations in outdoor air pollution concentrations.     

Soviet and post-Soviet environmental management: lessons from a case study on lead pollution

Through a case study on lead pollution in the former Soviet Union, the linkage of policy, environmental science, and environmental management is explored, and compared with the US experience. Soviet bans on leaded gasoline and lead-based paint appear to have been effective. Regional governments, in cooperation with the petroleum industry, are taking the initiative in phasing out leaded gasoline, to some extent in defiance of federal policy. Problems with management of lead-acid batteries have been worsened by the collapse of the political system. Lack of reliable environmental data impedes reliable environmental assessment. The types of environmental measurements reflect an emphasis on multipollutant environmental contamination, rather than on human exposure to single pollutants.     

A three-year study of air pollution episodes in a semi-rural area

Air pollution episodes in rural or semi-rural areas are strongly dependent upon wind directions relative to more or less distant industrial zones. At distances up to 80 km from emission sources acute episodes are observed which display pollutant levels of the same order of magnitude as the mean levels observed in industrial cities. It is shown that sulfur dioxide is an indicator of immissions of pollutant elements such as Br, As, Sb, Se, Cr and Zn.     

The CCMS air pollution model intercomparison study

Four air pollution transport models were tested and compared in an area of ~ 400 × 400 km². Three models were Eulcrian grid models, the fourth a Lagrangian trajectory model. The data base (emissions and meteorological observations) were essentially the same for all models. Differences in model output could only be a result of the different (numerical) structure of the models and of the differences in processing of the meteorological data. It turned out that the latter was the major source of differences in model results. Generally there was a satisfactory correlation between model results and observed concentrations. Mainly due to the negligence of transport of pollutants into the modelling region, predicted concentrations were considerably lower than the observed.     

Integrated biomonitoring of air quality with plants and lichens: a case study on ambient ozone from central Italy

A biennial integrated survey, based on the use of vascular plants for the bioindication of the effects of tropospheric ozone together with the use of automatic analysers of ozone, as well as the mapping of lichen biodiversity was performed in the area of Castelfiorentino (Tuscany, central Italy). Photochemically produced ozone proved to be a fundamental presence during the warm season, with maximum hourly means reaching 114 ppb, exceeding the information threshold as fixed by EU: the use of supersensitive tobacco Bel-W3 confirmed the opportunity of carrying out detailed cost-effective monitoring surveys. The potential for didactical and educational implications of this methodology are appealing. Critical levels set up for the protection of vegetation have exceeded considerably. The comparison of biomass productivity in sensitive and resistant individuals (NC-S and NC-R white clover clones, in the framework of an European network) provided evidence that ambient ozone levels are associated with relevant reduction (up to 30%) in the performance of sensitive material; effects on flowering were also pronounced. The economic assessment of such an impact deserves attention. Mapping of epiphytic lichen biodiversity – which has been used to monitor air quality worldwide – was not related to ozone geographical distribution as depicted by tobacco response.     

Lead (Pb) isotopic fingerprinting and its applications in lead pollution studies in China: A review

As the most widely scattered toxic metal in the world, the sources of lead (Pb) observed in contamination investigation are often difficult to identify. This review presents an overview of the principles, analysis, and applications of Pb isotopic fingerprinting in tracing the origins and transport pathways of Pb in the environment. It also summarizes the history and current status of lead pollution in China, and illustrates the power of Pb isotopic fingerprinting with examples of its recent applications in investigating the effectiveness of leaded gasoline phase-out on atmospheric lead pollution, and the sources of Pb found in various environmental media (plants, sediments, and aquatic organisms) in China. The limitations of Pb isotopic fingerprinting technique are discussed and a perspective on its development is also presented. Further methodological developments and more widespread instrument availability are expected to make isotopic fingerprinting one of the key tools in lead pollution investigation.     

Seasonal variation of air pollution index: Hong Kong case study

Air pollution is an important and popular topic in Hong Kong as concerns have been raised about the health impacts caused by vehicle exhausts in recent years. In Hong Kong, sulphur dioxide SO2, nitrogen dioxide (NO2), nitric oxide (NO), carbon monoxide (CO), and respirable suspended particulates (RSP) are major air pollutants caused by the dominant usage of diesel fuel by goods vehicles and buses. These major pollutants and the related secondary pollutant, e.g., ozone (O3), become and impose harmful impact on human health in Hong Kong area after the northern shifting of major industries to Mainland China. The air pollution index (API), a referential parameter describing air pollution levels, provides information to enhance the public awareness of air pollutions in time series since 1995. In this study, the varying trends of API and the levels of related air pollutants are analyzed based on the database monitored at a selected roadside air quality monitoring station, i.e., Causeway Bay, during 1999-2003. Firstly, the original measured pollutant data and the resultant APIs are analyzed statistically in different time series including daily, monthly, seasonal patterns. It is found that the daily mean APIs in seasonal period can be regarded as stationary time series. Secondly, the auto-regressive moving average (ARMA) method, implemented by Box-Jenkins model, is used to forecast the API time series in different seasonal specifications. The performance evaluations of the adopted models are also carried out and discussed according to Bayesian information criteria (BIC) and root mean square error (RMSE). The results indicate that the ARMA model can provide reliable, satisfactory predictions for the problem interested and is expecting to be an alternative tool for practical assessment and justification.     

Bivalve mollusks in metal pollution studies: From bioaccumulation to biomonitoring

Contemporary environmental challenges have emphasized the need to critically assess the use of bivalve mollusks in chemical monitoring (identification and quantification of pollutants) and biomonitoring (estimation of environmental quality). Many authors, however, have considered these approaches within a single context, i.e., as a means of chemical (e.g. metal) monitoring. Bivalves are able to accumulate substantial amounts of metals from ambient water, but evidence for the drastic effects of accumulated metals (e.g. as a TBT-induced shell deformation and imposex) on the health of bivalves has not been documented. Metal bioaccumulation is a key tool in biomonitoring; bioavailability, bioaccumulation, and toxicity of various metals in relation to bivalves are described in some detail including the development of biodynamic metal bioaccumulation model. Measuring metal in the whole-body or the tissue of bivalves themselves does not accurately represent true contamination levels in the environment; these data are critical for our understanding of contaminant trends at sampling sites. Only rarely has metal bioaccumulation been considered in combination with data on metal concentrations in parts of the ecosystem, observation of biomarkers and environmental parameters. Sclerochemistry is in its infancy and cannot be reliably used to provide insights into the pollution history recorded in shells. Alteration processes and mineral crystallization on the inner shell surface are presented here as a perspective tool for environmental studies.     

Involving the public in local air pollution assessment: a citizen participation case study

The central theme of this paper is that the assessment of environmental issues requires citizen participation for several reasons, including access to local knowledge, quality assurance and to reveal values and agendas. One methodology for involving the public is presented, based around the case of air pollution assessment in Sheffield. The study procedure of using citizen groups is described, and an analysis of the material from the groups is given. The final section argues that group discussions can be an appropriate methodology for involving the public in environmental assessment, and that the participants were able to comment on the validity and quality of such technical activities as continuous monitoring and computer modelling of air pollution in an urban environment.     

A new moss biomonitoring method for detecting sources of small scale pollution

A new simple method is proposed for identifying sources of small scale pollution, by determining the tissue concentrations of pollutants in terrestrial mosses. The method is based on spatial characterization of the processes that generate accumulation of pollutants in these organisms. The steps involved in implementing and applying the method are: (i) obtaining data on pollutants in moss samples collected at least at 35 pairs of sampling sites (SS) separated by 1 km distance; (ii) study of the distribution of the differences in concentration between the pairs of SS, eliminating pairs affected by foci that generate small scale processes; (iii) characterization of the resulting normal distributions and calculation, for different levels of significance, of the probability of a value lying within these distributions, and (iv) application of the calculated quantiles to data corresponding to the differences in concentrations between pairs of SS in the vicinities of foci of small scale pollution, to determine which elements can be considered as pollutants. Given the small number of data required once the distribution of the differences has been established, the method is an inexpensive, efficient way of establishing the probability that a pollutant is being emitted from a particular source. The method is very useful for verifying the results of pollution inventories, evaluating new technologies and improving the design of regional networks for biomonitoring of air quality with terrestrial mosses.     

Forecasting air pollution potential: a synoptic climatological approach

This paper describes the development and application of an air pollution potential (APP) forecast model based on a synoptic climatological approach in a heavily industrialized area in Durban, South Africa. The aim of the forecasting procedure, based on a system of orange, red, and all-clear alerts, was to give industry advance warning of periods of poor atmospheric dispersion so that it could take action to reduce emissions. The key meteorological parameter in accurately identifying the commencement of an APP episode was found to be negative surface pressure tendency. Wind direction was the most useful parameter in estimating the end point of an APP episode. The model was very successful in identifying periods of elevated SO2, but there is a need for further refinement in forecasting the end point of an episode.