Area Of Switzerland Research Articles

Selection of Multiple Umbrella Species for Functional and Taxonomic Diversity to Represent Urban Biodiversity

Surrogates, such as umbrella species, are commonly used to reduce the complexity of quantifying biodiversity for conservation purposes. The presence of umbrella species is often indicative of high taxonomic diversity; however, functional diversity is now recognized as an important metric for biodiversity and thus should be considered when choosing umbrella species. We identified umbrella species associated with high taxonomic and functional biodiversity in urban areas in Switzerland. We analyzed 39,752 individuals of 574 animal species from 96 study plots and 1397 presences of 262 plant species from 58 plots. Thirty-one biodiversity measures of 7 taxonomic groups (plants, spiders, bees, ground beetles, lady bugs, weevils and birds) were included in within- and across-taxa analyses. Sixteen measures were taxonomical (species richness and species diversity), whereas 15 were functional (species traits including mobility, resource use, and reproduction). We used indicator value analysis to identify umbrella species associated with single or multiple biodiversity measures. Many umbrella species were indicators of high biodiversity within their own taxonomic group (from 33.3% in weevils to 93.8% in birds), to a lesser extent they were indicators across taxa. Principal component analysis revealed that umbrella species for multiple measures of biodiversity represented different aspects of biodiversity, especially with respect to measures of taxonomic and functional diversity. Thus, even umbrella species for multiple measures of biodiversity were complementary in the biodiversity aspects they represented. Thus, the choice of umbrella species based solely on taxonomic diversity is questionable and may not represent biodiversity comprehensively. Our results suggest that, depending on conservation priorities, managers should choose multiple and complementary umbrella species to assess the state of biodiversity.

Is Switzerland suitable for the invasion of Aedes albopictus [corrected

BackgroundOver the last 30 years, the Asian tiger mosquito, Aedes albopictus, has rapidly spread around the world. The European distribution comprises the Mediterranean basin with a first appearance in Switzerland in 2003. Early identification of the most suitable areas in Switzerland allowing progressive invasion by this species is considered crucial to suggest adequate surveillance and control plans.Methodology/Principal FindingsWe identified the most suitable areas for invasion and establishment of Ae. albopictus in Switzerland. The potential distribution areas linked to the current climatic suitability were assessed using remotely sensed land surface temperature data recorded by the MODIS satellite sensors. Suitable areas for adult survival and overwintering of diapausing eggs were also identified for future climatic conditions, considering two different climate change scenarios (A1B, A2) for the periods 2020–2049 and 2045–2074. At present, the areas around Lake Geneva in western Switzerland provide suitable climatic conditions for Ae. albopictus. In northern Switzerland, parts of the Rhine valley, around Lake Constance, as well as the surroundings of Lake Neuchâtel, appear to be suitable for the survival at least of adult Ae. albopictus. However, these areas are characterized by winters currently being too cold for survival and development of diapausing eggs. In southern Switzerland, Ae. albopictus is already well-established, especially in the Canton of Ticino. For the years 2020–2049, the predicted possible spread of the tiger mosquito does not differ significantly from its potential current distribution. However, important expansions are obtained if the period is extended to the years 2045–2074, when Ae. albopictus may invade large new areas.Conclusions/SignificanceSeveral parts of Switzerland provide suitable climatic conditions for invasion and establishment of Ae. albopictus. The current distribution and rapid spread in other European countries suggest that the tiger mosquito will colonize new areas in Switzerland in the near future.

Modeling land use decisions with Bayesian networks: Spatially explicit analysis of driving forces on land use change

Land use decisions result from complex deliberative processes and fundamentally influence the livelihoods of many. These decisions are made based on quantitatively measurable information like topography and on qualitative criteria such as personal preferences. Bayesian networks (BN) are able to integrate both quantitative and qualitative data and are thus suitable to approach such processes. We model land use decisions in a pre-Alpine area in Switzerland, integrating biophysical data and local actors' knowledge into a spatially explicit BN. A structured experts' process to elaborate three different BN including agriculture, forestry, and settlement provides the base for the modeling. A spatially explicit updating of the BN via questionnaires enables us to take local actors' characteristics into account. Results show which drivers are most important for land use decision-making in our case study region, and how an alteration of these drivers could change future land use. Furthermore, focusing on the probability of occurrence of various land uses in a spatially explicit manner gives insights into path-dependency of land use change. This knowledge can serve as information for planners and policy makers to design more effective policy instruments.

A comparison between two statistical and a physically-based model in snow water equivalent mapping

Snow water equivalent (SWE) estimates at the end of the winter season have been compared for the 2002–2006 period in a 200km2 mountainous area in Switzerland, using three different models. The first model, ALPINE3D, is a physically based process-oriented model, which solves the snowpack energy and mass balance equations. The other two models, SWE-SEM and HS-SWE, are statistical algorithms interpolating snow data on a grid. While SWE-SEM interpolates local estimates of SWE, HS-SWE converts interpolated snow depth maps into maps of SWE using a regionally-calibrated conversion model. We discuss similarities and differences among the models’ results, both in terms of total volume, and spatial distribution of SWE. The comparison shows a general good agreement of the results of the three models, with a mean difference in the total volumes between the two statistical models of ∼8%, and between the physical model and the statistical ones of ∼−3% to −10%.

SPATIOTEMPORAL VARIATION OF PARTICLE NUMBER AND SURFACE AREA CONCENTRATION IN FOUR SWISS AREAS AND ITS RELATIONSHIP WITH MASS MEASUREMENTS

Background: This study is part of the Swiss Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA), a cohort study initiated in 1990 and spread across eight geographically diverse areas in Switzerland. Innovative exposure modeling has been conducted in SAPALDIA earlier for PM10 and NO2, however, exposure to specific traffic related pollutants such as ultrafine particles and PM constituents has not been assessed. Aims:The overarching aim is to provide the estimates of individual long-term outdoor traffic-related air pollution exposures of the cohort participants. This paper focuses on the spatial and temporal variation of home outdoor particle number (PN) and lung-deposited surface area (LDSA) concentration in four study areas: Basel, Geneva, Lugano and Wald. Methods: Weekly outdoor PN and LDSA are measured at 20 residences each in four study areas in three seasons over a period of 2 years, 2011-2012. PN and LDSA are measured using a portable particle counter, miniDiSC (miniature diffusion size classifier). It is a portable diffusion charging based device and measures nanometer sized (10-300nm) particles with a time-resolution of one second. Results: Mean weekly outdoor PN levels aggregated across all seasons and sites are 11000±3700, 15400±8430 and 15700±7200 particles/cm3 in Basel, Geneva and Lugano, respectively. As expected, PN are highest in winter and lowest in summer for all study areas/sites. PN levels show a clear morning and evening rush hour in all seasons in all sites, but more prominently at street sites. PN shows reasonably moderate correlation with NO2 but poor to no correlation with other PM mass metrics in all seasons. Analysis of LDSA measurements and comparison with PN and other pollutants is currently underway. Conclusions: Our results show significant seasonal and spatial variation in home outdoor PN levels within and between study areas and document the differential impact of traffic on PN levels in all study areas.

The SAPALDIA cohort: design and results in the field of respiratory and cardio-vascular diseases

The SAPALDIA (Swiss Study on Air Pollution and Lung Disease in Adults) cohort involving eight geographical areas of Switzerland was initiated in 1991 for studying the effects of air pollution on the respiratory and cardiovascular health in adults. The study was initiated with a cross-sectional interview of 9651 subjects aged 18 to 60 years and more than 90% of them underwent lung function and atopy testing. More than 7000 of the subjects had bronchial reactivity tested by a methacholine challenge. The address histories of the participants were carefully followed up and a follow up assessment was done in 2002 (SAPALDIA 2). A second follow-up was done in 2010-11. In the 2002 follow-up, 8047 (83%) provided health information, 6528 persons underwent physical re-examination, and 6345 provided blood samples to establish an extensive blood, plasma, serum and DNA bank. In addition, 1813 subjects aged 50 or older participated in 24h-ECG Holter monitoring to provide detailed data on parameters of heart rate variability as an early marker of cardiac response to the environment. With the inclusion of cardiovascular endpoints, SAPALDIA is one of the first studies examining effects from long-term exposure to air pollution on cardiovascular health parameters as well as mutual influence between the respiratory and the cardiovascular system. A paper validating the prediction model for individual exposure to PM10 particles was published and another paper published in the New England Journal of Medicine demonstrates that outdoor air pollution is associated with the evolution of individual lung function in adults. The SAPALDIA bio-bank has allowed scientific publications on the association between gene polymorphisms and the propensity to develop asthma, allergic diseases, or accelerated lung function decline with age. Ongoing studies are focusing on gene-environment interactions a crucial question to understand why some persons suffer more from the effect of air pollution than others. The recent publications by the SAPALDIA team have addressed the key questions of the project: i) the impact of air pollution on respiratory and cardio-vascular health in a longitudinal perspective; ii) the role of genetic factors in modifying health effects from the environment, and iii) the complex interactions between respiratory and cardiovascular health. Further studies and refinements are necessary to address many unresolved issues. These require extensive collaborations, particularly in the fields of exposure assessment and genetic associations.

Unravelling landscape variables with multiple approaches to overcome scarce species knowledge: a landscape genetic study of the slow worm

Landscape genetics was developed to detect landscape elements shaping genetic population structure, including the effects of fragmentation. Multifarious environmental variables can influence gene flow in different ways and expert knowledge is frequently used to construct friction maps. However, the extent of the migration and the movement of single individuals are frequently unknown, especially for non-model species, and friction maps only based on expert knowledge can be misleading. In this study, we used three different methods: isolation by distance (IBD), least-cost modelling and a strip-based approach to disentangle the human implication in the fragmentation process in the slow worm (Anguis fragilis), as well as the specific landscape elements shaping the genetic structure in a highly anthropized 16 km2 area in Switzerland. Friction maps were constructed using expert opinion, but also based on the combination of all possible weightings for all landscape elements. The IBD indicated a significant effect of geographic distance on genetic differentiation. Further approaches demonstrated that highways and railways were the most important elements impeding the gene flow in this area. Surprisingly, we also found that agricultural areas and dense forests seemed to be used as dispersal corridors. These results confirmed that the slow worm has relatively unspecific habitat requirements. Finally, we showed that our models based on expert knowledge performed poorly compared to cautious analysis of each variable. This study demonstrated that landscape genetic analyses should take expert knowledge with caution and exhaustive analyses of each landscape element without a priori knowledge and different methods can be recommended.

Treatment and Early Intervention in Psychosis Program (TIPP‐Lausanne): implementation of an early intervention programme for psychosis in Switzerland

In a survey conducted in the Lausanne catchment area in 2000, we could estimate on the basis of file assessment that first-episode psychosis (FEP) patients had psychotic symptoms for more than 2 years before treatment and that 50% did not attend any outpatient appointment after discharge from hospital. In this paper, we describe the implementation of a specialized programme aimed at improving engagement and quality of treatment for early psychosis patients in the Lausanne catchment area in Switzerland. The Treatment and Early Intervention in Psychosis Program-Lausanne is a comprehensive 3-year programme composed of (i) an outpatient clinic based on assertive case management; (ii) a specialized inpatient unit; and (iii) an intensive mobile team, connected for research to the Center for Psychiatric Neuroscience. Eight years after implementation, the programme has included 350 patients with a disengagement rate of 9% over 3 years of treatment. All patients have been assessed prospectively and 90 participated in neurobiological research. Based on this experience, the Health Department funded the implementation of similar programmes in other parts of the state, covering a total population of 540,000 people. Programmes for early intervention in psychosis have a major impact on patients' engagement into treatment. While development of mobile teams and assertive case management with specific training are crucial, they do not necessitate massive financial support to be started. Inclusion of a research component is important as well, in terms of service planning and improvement of both quality of care and impact of early intervention strategies.

Urban aquatic ecosystems: Habitat loss and depletion of native macrophyte diversity during the 20th century in four Swiss cities

Urban areas are among the most affected by human activities. In Europe, urbanization has essentially occurred since the end of the 19th century. However, the influence of this dramatic process on aquatic ecosystems has rarely been quantified and analyzed using historical data. In this study, we investigate the evolution of the hydrological system and native aquatic macrophytes in urban areas between the end of the 19th century and the beginning of the 21st century. Four urban areas in Switzerland were chosen for the analyses, Zürich, Basel, Lausanne and Fribourg, and we analyzed the changes in aquatic plant diversity based on the historical and recent floristic data available for the same areas and the same time periods. Our results show that a significant proportion (∼30 %) of aquatic habitats has disappeared from the investigated locales during the last 130 years and that the extinction rate of the aquatic plant species is notably higher in the studied cities (28 %) than in Switzerland as a whole (2 %). Thus, between the end of the 19th and the beginning of the 21st centuries, urban development in Swiss cities has prompted a degradation of aquatic habitats that resulted in a significant reduction of the aquatic biodiversity. However, our study shows that urban areas still have the capacity to shelter a large diversity of aquatic organisms, including some of the most threatened species. Thus, it is important to integrate urban areas in the conservation strategies for these species.

Identifying Stakeholders' Views on Sustainable Urban Transition: Desirability, Utility and Probability Assessments of Scenarios

The assessment of different urban planning scenarios by stakeholders can yield important insights which, in turn, inform sustainable urban transition. Yet to gain in-depth insight, this assessment needs to be multi-faceted and should go beyond a unidimensional “most/least desired” approach. Accordingly, we use indicators that distinguish between desirability, utility and probability assessments. We compare these assessments within and between various stakeholder groups based on a set of literature-based hypotheses. We constructed six planning scenarios, systematically varied with respect to sustainability for the case study, “Erlenmatt”, a major urban redevelopment area in Switzerland. Three stakeholder groups (housing suppliers, the non-profit & public sector and housing target groups, n = 80) were investigated. The results of the statistical analyses suggest that more sustainable scenarios are preferred with respect to both their desirability and utility and that their probability is not lower than that of the other scenarios. The non-profit & public sector is the most pessimistic about the probability of a sustainable district while housing suppliers desire it less. We conclude that such detailed subjective scenario assessments can provide informative and detailed guidance for sustainable urban transition.

Seasonality ofIxodes ricinusTicks on Vegetation and on Rodents andBorrelia burgdorferisensu lato Genospecies Diversity in Two Lyme Borreliosis–Endemic Areas in Switzerland

We compared Ixodes ricinus questing density, the infestation of rodents by immature stages, and the diversity of Borrelia burgdorferi sensu lato (sl) in questing ticks and ticks collected from rodents in two Lyme borreliosis (LB)-endemic areas in Switzerland (Portes-Rouges [PR] and Staatswald [SW]) from 2003 to 2005. There were variations in the seasonal pattern of questing tick densities among years. Questing nymphs were globally more abundant at PR than at SW, but the proportion of rodents infested by immature ticks was similar (59.4% and 61%, respectively). Questing tick activity lasted from February to November with a strong decline in June. The seasonal pattern of ticks infesting rodents was different. Ticks infested rodents without decline in summer, suggesting that the risk of being bitten by ticks remains high during the summer. Rodents from SW showed the highest infestation levels (10±21.6 for larvae and 0.54±1.65 for nymphs). The proportion of rodents infested simultaneously by larvae and nymphs (co-feeding ticks) was higher at SW (28%) than at PR (11%). Apodemus flavicollis was the species the most frequently infested by co-feeding ticks, and Myodes glareolus was the most infective rodent species as measured by xenodiagnosis. At PR, the prevalence of B. burgdorferi sl in questing ticks was higher (17.8% for nymphs and 32.4% for adults) than at SW (10.4% for nymphs and 24.8% for adults), with B. afzelii as the dominant species, but B. garinii, B. burgdorferi sensu stricto, and B. valaisiana were also detected. Rodents transmitted only B. afzelii (at PR and at SW) and B. bavariensis (at SW) to ticks, and no mixed infection by additional genospecies was observed in co-feeding ticks. This implies that co-feeding transmission does not contribute to genospecies diversity. However, persistent infections in rodents and co-feeding transmission contribute to the perpetuation of B. afzelii in nature.

Leaching of Biocides from Façades under Natural Weather Conditions

Biocides are included in organic building façade coatings as protection against biological attack by algae and fungi but have the potential to enter the environment via leaching into runoff from wind driven rain. The following field study correlates wind driven rain to runoff and measured the release of several commonly used organic biocides (terbutryn, Irgarol 1051, diuron, isoproturon, OIT, DCOIT) in organic façade coatings from four coating systems. During one year of exposure of a west oriented model house façade in the Zurich, Switzerland area, an average of 62.7 L/m(2), or 6.3% of annual precipitation came off the four façade panels installed as runoff. The ISO method for calculating wind driven rain loads is adapted to predict runoff and can be used in the calculation of emissions in the field. Biocide concentrations tend to be higher in the early lifetime of the coatings and then reach fairly consistent levels later, generally ranging on the order of mg/L or hundreds of μg/L. On the basis of the amount remaining in the film after exposure, the occurrence of transformation products, and the calculated amounts in the leachate, degradation plays a significant role in the overall mass balance.

Acoustical performance assessment of Swiss low-noise road surface solutions in urban areas

Recently Switzerland has experienced a new momentum in the construction of low-noise road surfaces in order to combat traffic noise in urban areas. Various regions have taken action and developed individual approaches to reduce traffic noise at the source. As a result, new requirements on the acoustical properties or on the void content of road surfaces were imposed, leading to the development of new products. The present work aims at both summarizing and cross comparing the acoustical performance of these products as well as analyzing the data produced to understand how the noise reduction was achieved. A large number of road surfaces (50 thin-layer asphalts, 30 SMA-like surfaces with increased void content) were therefore subjected to acoustical property monitoring using the CPX (close proximity) method. The acoustical performance of these road surfaces was quantified and evaluated in respect to AC and SMA surfaces, commonly used in urban areas in Switzerland and elsewhere in Europe. An approach was developed where measurement data of surface texture, airflow resistance and sound absorption, combined with SPERoN modeling (a tyre/road surface contact model) was included in the analyses. This approach provided an evaluation of the contribution of isolated factors to the overall noise reduction.

Serological Evidence of Tick-Borne Encephalitis Virus Infection in Rodents Captured at Four Sites in Switzerland

In a previous study, the presence of tick-borne encephalitis virus (TBEV) in questing Ixodes ricinus L. ticks and in field derived ticks that engorged on small mammals (n = 9,986) was investigated at four sites located in a TBE area in Switzerland. Two of these sites were already recognized as TBE foci (Thun and Belp) and the screening of ticks revealed the presence of TBEV in ticks at a third site, Kiesen, but not at the fourth one, Trimstein. The aim here was to test another approach to detect TBE endemic areas. Sera from 333 small mammals (Apodemus flavicollis, A. sylvaticus, Myodes glareolus) captured in 2006 and 2007 at the four sites were examined for the presence of antibodies against TBEV using immunofluorescence and avidity tests. Overall the prevalence of antibodies against TBEV in rodents reached 3.6% (12/333). At two sites known as TBE foci, Thun and Belp, anti-TBEV antibodies were detected in 9.9% (9/91) and 1.6% (1/63) of rodent sera, respectively. At the third site, Kiesen, recently identified as a TBE focus by the detection of TBEV in ticks, anti-TBEV antibodies were detected in 1.8% (2/113) of rodent sera. Finally, at Trimstein, none of the examined rodent sera had antibodies against TBEV (0/66). This study shows another approach to detect TBE foci by testing antibodies in small mammal sera that is less time-consuming and less expensive than molecular tools.

Comparative Coverage of Supplementary and Universally Recommended Immunizations in Children at 24 Months of Age

The introduction of pneumococcal and meningococcal group C conjugate vaccinations as supplementary (a new category in Swiss immunization recommendations) to universally recommended vaccinations in 2006 prompted this study to investigate their acceptance. The study was performed in 24-month-old healthy children born in the Geneva or Basel areas in Switzerland between January and April 2007. After informed consent had been obtained from caregivers (for this particular study in Basel and in general for providing immunization data in Geneva on an ongoing basis), all universally recommended and supplementary vaccinations administered by ≤24 months of age were analyzed for completeness and timeliness according to set definitions. Sample size calculations and standard statistical tests were applied for comparative data analyses. Of 592 children at the age of 12 months, 94% and 73% had received complete diphtheria-tetanus-pertussis component combination and pneumococcal conjugate vaccinations, respectively. At the age of 24 months, coverage rates for complete booster doses were 77% and 70%, respectively. Rates for MMR doses 1 and 2 at 24 months were 92% and 72%, respectively, and the rate for meningococcal conjugate vaccine (single dose) was 62%. On an average, coverage rates were similar in the 2 study regions except those for pneumococcal conjugate and second dose of MMR, which were approximately 10% higher in Geneva. Compliance with supplementary vaccinations was lower than that with universally recommended vaccinations. This can be explained by the recent introduction of supplementary vaccinations or by the public perception that they are less important than universal vaccinations.

Ammonia emissions and emission factors of naturally ventilated dairy housing with solid floors and an outdoor exercise area in Switzerland

From an agricultural and environmental policy perspective there is a pressing need for up-to-date emission data on ammonia (NH 3 ) from dairy farming. The main aim of this study was to determine NH 3 emissions for the most common dairy farming situation in Switzerland of loose housing with an outdoor exercise area. Measurements were taken on six commercial farms, in naturally ventilated cubicle loose housing systems with solid floors and an outdoor exercise area located alongside the housing. The variation in climate over the course of a year was covered by a total of twelve measuring periods, in two out of three seasons (summer, transition period, winter) per farm. A tracer ratio method with two tracer gases (SF 6 , SF 5 CF 3 ) was employed to determine emissions from two areas of different source intensity. A variety of accompanying parameters was used to characterise each measuring situation and to derive the relevant influencing variables. The daily average NH 3 emission across all farms varied from 31 to 67 g LU −1 d −1 in summer, from 16 to 44 g LU −1 d −1 in the transition period, and from 6 to 23 g LU −1 d −1 in winter (1 LU = 500 kg live weight). From a linear mixed-effects model the wind speed in the housing ( p < 0.001) and the interaction of outside temperature and the urea content of the tank milk ( p < 0.001) emerged as significant variables influencing NH 3 emission. A model-based calculation with bootstrapped variance components was used to calculate yearly averaged emission factors for two mountain and plain regions and two wind speeds (0.3 and 0.5 m s −1 ). The model input was based on milk urea contents from commercial dairy farms and air temperatures over a five-year period. The calculated NH 3 emission factors, which thus accounted for regional differences due to climatic conditions and feeding levels, ranged between 22 and 25 g LU −1 d −1 . ► NH 3 emissions were determined for naturally ventilated dairies with outdoor areas. ► A tracer ratio method with SF 6 and SF 5 CF 3 enabled to quantify NH 3 emissions. ► NH 3 emission was influenced by wind speed, temperature and tank milk urea content. ► A multi-site sampling approach depicted seasonal and farm effects. ► NH 3 emission factors for naturally ventilated dairies ranged from 22-25 g LU −1 d −1 .

Spatially explicit inverse modeling for urban planning

Urban modeling methods have traditionally followed a forward modeling approach. That is, they use data from today’s situation to forecast or simulate future states of an urban system. In this paper, we propose an inverse modeling approach by which we shift our attention from solely forecasting or simulating future states of an urban system to steering it to a desired state in the future via key variables characterizing the system in the present. We first present a theoretical framework for the use of the inverse approach in urban planning. We test the power of the proposed method using a hedonic house price model in a metropolitan area in Switzerland to investigate the negative effects of densification on house prices. The model is calibrated by mixed geographically weighted regression in order to account for spatial variability of both key variables and model outputs. We show how devaluation of house prices caused by densification can be compensated by different levels of socioeconomic, locational as well as structural variables. We illustrate and discuss how trade-offs between variables may lead to more feasible results from an urban planning perspective. We conclude that the proposed method might be valuable for urban planners for developing implementable spatial plans based on future visions. In particular, the fact that other model specifications than hedonic house price model can also be employed to formulate an inverse model application, allows planners to address other type of problems or externalities from urbanization processes such as urban sprawls, environmental pollution or land uses change.

Long-term exposure models for traffic related NO2 across geographically diverse areas over separate years

Although recent air pollution epidemiologic studies have embraced land-use regression models for estimating outdoor traffic exposure, few have examined the spatio-temporal variability of traffic related pollution over a long term period and the optimal methods to take these factors into account for exposure estimates. We used home outdoor NO 2 measurements taken from eight geographically diverse areas to examine spatio-temporal variations, construct, and evaluate models that could best predict the within-city contrasts in observations. Passive NO 2 measurements were taken outside of up to 100 residences per area over three seasons in 1993 and 2003 as part of the Swiss cohort study on air pollution and lung and heart disease in adults (SAPALDIA). The spatio-temporal variation of NO 2 differed by area and year. Regression models constructed using the annual NO 2 means from central monitoring stations and geographic parameters predicted home outdoor NO 2 levels better than a dispersion model. However, both the regression and dispersion models underestimated the within-city contrasts of NO 2 levels. Our results indicated that the best models should be constructed for individual areas and years, and would use the dispersion estimates as the urban background, geographic information system (GIS) parameters to enhance local characteristics, and temporal and meteorological variables to capture changing local dynamics. Such models would be powerful tools for assessing health effects from long-term exposure to air pollution in a large cohort. ► Long-term exposure models developed for 8 different areas in Switzerland. ► Unique comparison of LUR models using seasonal NO 2 measurements made a decade apart. ► Best LUR models used land-use, dispersion, meteorological, and temporal predictors. ► Individual local area models by year best captured NO 2 spatial distribution. ► Implications on the generalizability of LUR models for air pollution health studies.

SPATIO-TEMPORAL VARIATION OF PARTICLE NUMBER CONCENTRATIONS IN A SWISS URBAN CITY

Background and Aims: This study is part of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA), a nearly 20-year old cohort study spread in 8 geographically diverse areas in Switzerland. Innovative exposure modeling has been conducted in SAPALDIA earlier for PM10 and NO2, however, exposure to specific traffic related pollutants such as ultrafine particles and PM constituents has not been assessed. The overarching aim is to provide the estimates of individual long-term outdoor traffic-related air pollution exposures of the cohort participants. This paper focuses on the spatial and temporal variation of home outdoor particle number concentration (PN) in one of the SAPALDIA area, Basel. Methods: The PN measurements will be conducted at 20 residences each in four of the eight areas in three seasons over a period of 2 years, 2011-2012. Indoors and outdoors monitoring will be conducted biweekly for PM2.5, PM10, NO2 and weekly for PN. Particle counts are measured using a particle counting device, miniDiSC (miniature diffusion size classifier). It is a portable device and measures nanometer sized (10-300nm) particles with a resolution of one second. Results: Mean weekly averaged PN levels are observed 14529±3296, 13659±1878 and 11545 particles/cm3 at street, urban and regional background locations respectively. Median correlation coefficient for all sites is 0.70 (range 0.36-0.91) and 0.83 (range 0.39-0.99) for hourly and daily PN respectively. Median coefficient of divergence, a measure of spatial heterogeneity, for all site pairs is 0.15 (range 0.05-0.27), showing a low to mid spatial heterogeneity in daily PN in Basel. These winter season observations will be compared across seasons and further with concurrent PM2.5, PM10 and NO2 measurements. Conclusions: Our first results show significant differences in PN levels in home outdoor locations and document the differential impact of traffic on PN levels in the city.

Waldflächenentwicklung der letzten 120 Jahre in der Schweiz

Development of forest area in Switzerland within the last 120 years Historical maps provide a useful source for spatial landscape analyses as they represent a generalized reflection of geographical reality over large areas at a certain time. Digitization and georeferencing of analog maps help to make such analyses more efficient. In Switzerland, the forest area has grown since the mid 19th century according to statistics of the federal government and the cantons. These statistics, however, provide a limited basis for regional analyses of changes in forest area. In this study, the forest areas in 1880, 1915, 1940 and 2000 were estimated based on analyses of the Topographical Atlas of Switzerland (Siegfried maps [1880Siegfried maps [1915, and 1940]), and of the Topographical Map (2000). Using a sample of 20 638 plots, analogous to the aerial photo-interpretation of the Swiss National Forest Inventory (NFI), a forest/non-forest decision was made for each time cutting. Overall, in Switzerland the forest area increased by 21.6% from 1880 to 2000. This is much less than what revealed the analysis of statistical sources due to differences in the methods and forest definitions used. Considerable regional differences could be detected, with one general trend from north to south and another from east to west. In most regions with strong urban development, the forest area is stagnating or has slightly decreased. The increase in forest cover has taken place mainly in the Alps and the Southern Alps.