| 1. |
- Annika, Hagenbjörk-Gustafsson, et al.
(författare)
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Spatial variation of ground level ozone and the relation between ozone and NO2/NOx in two Swedish cities
- 2013
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Konferensbidrag (refereegranskat)abstract
- Background Ozone is a pollutant known to cause adverse effects on human health. It is formed by reactions between nitrogen oxides (NOx) and hydrocarbons under the influence of sunlight. In urban areas ozone is consumed oxidating nitrogen oxide (NO) to nitrogen dioxide (NO2). Despite the potential to cause adverse health effects, the local spatial distribution of ozone and the relationship between ozone, NO2 and NOx in different environments is poorly studied.Aims Our aim was to study the concentrations and spatial distribution of ozone in two cities, Malmö in the south of Sweden and Umeå in the north of Sweden, since the contribution of ozone from other parts of Europe decreases with higher latitude. We also wanted to investigate differences in the ozone/NO2 and the ozone/NOx ratios between the cities and between different environments.Methods Ozone, NO2 and NOx concentrations were measured with Ogawa diffusive samplers during three one-week campaigns in April, May/June and in August 2012. Measurements were conducted simultaneously at 20 sites in each city outside preschools, distributed at traffic sites, urban background sites and regional background (rural) sites. Results The average concentration of ozone in Malmö and Umeå were 67,5 µg/m3 and 50,6 µg/m3, respectively. The mean ozone/NOx ratio was of equal magnitude in Malmö and in Umeå, and in both cities the ratio was highest at rural sites and lowest at traffic sites. In Umeå there was a clear trend with highest ozone concentrations at rural sites and lowest concentrations at traffic sites, a trend that was not as obvious in Malmö. In Umeå the ozone/NO2 ratio at rural sites was about three times larger compared to Malmö.Conclusions There is a clear local variation of ozone, with stronger gradients in northern (Umeå) Sweden in comparison to southern Sweden (Malmö). This can partly be explained by less long-range transport of ozone and larger impact of local NO emissions that reduce ozone in northern Sweden.
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| 2. |
- Delcloo, Andy, et al.
(författare)
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ACCEPTED : An Assessment of Changing Conditions, Environmental Policies, Time-Activities, Exposure and Disease
- 2014
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Ingår i: Air Pollution Modeling and its Application XXIII. - Cham : SPRINGER-VERLAG BERLIN. ; , s. 55-59
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Konferensbidrag (refereegranskat)abstract
- Changes in urban design and traffic policy, demography, climate and associated adaptation, mitigation measures and environmental policies are likely to modify both outdoor and indoor air quality and therefore public health. The project aims to improve our understanding of future exposure situations and their impact on health, from an interdisciplinary approach. This will be achieved by using various state-of-the-art atmospheric models, measurements, epidemiological studies and reviews. To assess population full exposure, an integrated view accounting both for indoor and outdoor air pollution as well as for population time activity data will be developed. New dose-response functions will be estimated between health outcome, air pollution and temperature in order to better estimate the effects on the foetus and young children. Ultimately, scenarios of future urban climate and air quality will be simulated, combining future exposure scenarios, population scenarios and exposure-response functions to describe the effects of different trends and relevant policies on relative risk and burden of illness attributed to urban pollutants and their interactions with extreme temperatures. Also the mitigation strategies that can be used to reduce urbanization and climate change effects on the local urban meteorology and air quality will be assessed. With applications in several large European cities, the project will study the impact of several alternative adaptation scenarios on urban air quality and human health to a mid-century horizon (2030-2060) accounting for the effects of a changing urban climate. Scenario-based health impact assessments will combine exposure information from climate models, emission scenarios, policy evaluation studies and concentration calculations with exposure-response functions from epidemiological studies of vulnerable groups within the project and previously published functions for mortality and hospital admissions. The effects of socioeconomic and demographic trends will be discussed, the predicted health impacts and benefits associated with different interventions and policies and other urban changes will be described.
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| 3. |
- Forsberg, Bertil, et al.
(författare)
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Short-Term Effects of Air Pollution on Daily Emergency Visits for Asthma and Copd At Hospitals in Stockholm
- 2004
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Ingår i: The Sixteenth Conference of the International Society for Environmental Epidemiology (ISEE). - Cambridge, MA : Blackwell Scientific Publications. ; , s. 58-
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Konferensbidrag (refereegranskat)abstract
- A large number of studies have analysed air pollution effects on hospital admissions for respiratory diseases. Not so many have dealt with effects on emergency room visits. We have studied the associations between ambient pollution levels and emergency visits for asthma and Chronic Obstructive Pulmonary Disease (COPD) at seven hospitals in Greater Stockholm. Data on daily numbers of respiratory emergency visits, including ICD codes, were obtained from registers kept by the County council. We studied the period 1998-2002. Air pollution data were obtained from the main monitoring station, indicating the urban background concentration of PM10 (TEOM), NO2 and ozone. The daily pollen concentration from one measurement site in the city was also used. Weather data (temperature, relative humidity) were collected from an official weather station at the City airport. The mean concentration was 59 μg/m3 for ozone, 17 μg/m3 for NO2 and 16 μg/m3 for PM10. The mean daily number of emergency visits was 12 for asthma and 3 for COPD. Data were analysed using generalised additive models assuming an overdispersed Poisson model, and estimated using a quasi-likelihood approach. For asthma autoregressive terms were added to the model. We adjusted for season, day of week and weather. If the model was improved, we included also a pollen variable (asthma) and the number of influenza visits. The first analysis has been focussed on the effect of the mean air pollution levels during the last two days (lag 01). We used both single pollutant models, two pollutant models and finally a full model with the three pollutants included simultaneously. Ozone was significant in all COPD models, while the other pollutants never had any significant associations. In the full model the ozone effect was 3% per 10 μg/m3. For all asthma no pollutant had any significant effect, but for the largest subgroup (J45.9; unspecified asthma, here representing two thirds of the asthma visits) ozone significantly increased the number of visits. The estimate was about 2% per 10 μg/m3 in all models. These coefficients are rather high in comparison with other studies, but not high when compared with the ozone effect on respiratory hospital admissions in Stockholm. We conclude that ozone from an health point of view is an important air pollutant in this area.
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| 4. |
- Forsberg, Håkan, et al.
(författare)
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A scalable and pipelined embedded signal processing system using optical hypercube interconnects
- 2000
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Ingår i: Proceedings of the 12th IASTED International Conference on Parallel and Distributed Computing and Systems (PDCS 2000), Las Vegas, NV, USA, Nov. 6-9, 2000. - Las Vegas : IASTED. ; , s. 265-272
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a system suitable for embedded signal processing with extreme performance demands. The system consists of several computational modules that work independently and send data simultaneously in order to achieve high throughput. Each computational module is composed of multiple processors connected in a hypercube topology to meet scalability and high bisection bandwidth requirements. Free-space optical interconnects and planar packaging technology make it possible to transform the hypercubes into planes and to take advantage of many optical properties. For instance, optical fan-out reduces hardware cost. This, altogether, makes the system capable of meeting high performance demands in, e.g., massively parallel signal processing. An example system with eleven computational modules and an overall peak performance greater than 2.8 TFLOPS is presented. The effective inter-module bandwidth in this configuration is 1,024 Gbit/s.
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| 5. |
- Forsberg, Håkan, et al.
(författare)
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Key Issues in Implementing an Optoelectronic Planar Free-space Architecture for Signal Processing Applications
- 2003
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Ingår i: IASTED International Multi-Conference on Applied Informatics. - : IASTED/ACTA Press. - 0889863415 ; , s. 621-629
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Konferensbidrag (populärvet., debatt m.m.)abstract
- In this paper, we deal with the key issues in implementing an optoelectronic architecture suitable for embedded signal processing. The architecture is based on a system concept where free-space optical interconnects and planar packaging technologies make it possible to merge complicated and new parallel computer architectures into planes and to take advantage of many properties of optics. For instance, optical fan-out reduces the hardware cost as well as the all-to-all broadcast time. It is also possible to meet scalability and high bisection bandwidth requirements. The main results show that it is possible to build a 6D hypercube using planar optical substrates.
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| 6. |
- Forsberg, Håkan, 1969-, et al.
(författare)
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Opportunities for Optical Planar Interconnection Technology in Terabit Switches
- 2003
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Ingår i: Proceedings of the IASTED International Conference on Wireless and Optical Communications, July 2-4, 2003, Banff, Canada. - Anaheim; Calgary : ACTA Press. - 0889863741 - 9780889863743 ; , s. 155-164
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Konferensbidrag (refereegranskat)abstract
- To keep up with the explosive growth of world-wide network traffic, large-capacity switches, with switching capacities in excess of several terabits per second, are becoming an essential part of the future. To realize such switches, new architecture concepts must be considered. In this paper, we discuss a technology for terabit switches that combines the advantage of using optical communication in all three spatial dimensions and the benefits of using surface mounted optoelectronic as well as electronic chips. We present three different types of packet-based switch fabrics, all based on the optical planar interconnection technology. We then discuss these in terms of capacity, scalability, and physical size. All three implementations have a single switch plane cross sectional bandwidth exceeding 5 Tbps.
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| 7. |
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| 8. |
- Forsberg, Håkan, et al.
(författare)
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Radar signal processing using pipelined optical hypercube interconnects
- 2001
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Ingår i: Proceedings of the 15th International Parallel and Distributed Processing Symposium. - Los Alamitos, California : IEEE Computer Society Press. - 0769509908 ; , s. 2043-2052
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider the mapping of two radar algorithms on a new scalable hardware architecture. The architecture consists of several computational modules that work independently and send data simultaneously in order to achieve high throughput. Each computational module is composed of multiple processors connected in a hypercube topology to meet scalability and high bisection bandwidth requirements. Free-space optical interconnects and planar packaging technology make it possible to transform the hypercubes into planes. Optical fan-out reduces the number of optical transmitters and thus the hardware cost. Two example systems are analyzed and mapped onto the architecture. One 64-channel airborne radar system with a sustained computational load of more than 1.6 TFLOPS, and one ground-based 128-channel radar system with extreme inter-processor communication demands.
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| 9. |
- Lövenheim, Boel, et al.
(författare)
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Health risk assessment of reduced air pollution exposure when changing commuting by car to bike
- 2016
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Konferensbidrag (refereegranskat)abstract
- In this study we have assessed the reduction in traffic emissions and population exposure assuming all potential car commuters would switch to biking if they live within 30 minute travel by bike. The scenario would result in more than 100 000 new bikers and due to the reduced traffic emissions 42 premature deaths would be avoided per year. This is almost twice as large effect as the congestion tax in Stockholm. Introduction Regular physical activity has important and wide-ranging health benefits including reduced risk of chronic disease, and physical inactivity is mentioned as perhaps the most important public health problem of the 21st century. At the same time, the direct effects of traffic emissions is a major health problem. Transferring commuting by car to bike will increase physical activity and reduce emissions and reduce population exposure to traffic pollution. The exposure of commuters will also change; new bikers may get higher exposure whilst old bikers and car drivers may get lower exposures, depending on commuting route and distance. Methodology In this study we have calculated the potential number of car-to-bike switching commuters depending on distance, travel time, age of commuters, etc. We have made calculations for a 30-minute biking scenario, i.e. transferring all car commuters to bike if their travel time by bike is less than or equal to 30 minutes. The commuting distance depends on age and sex. For the travel and traffic modelling the LuTrans model was used. It includes all different modes of travel; walking, bicycling, public transport systems and car traffic. The model was developed based on travel survey data and is regularly calibrated using traffic counts. Emissions from road traffic were calculated based on HBEFA 3.2. A Gaussian dispersion model was used estimate exposures over the county of Stockholm. Results The 30 min scenario resulted in 106 881 more bikers, an increase of 2.6 times compared to base scenario. Of all bikers 50% were men and the mean age of all bikers was 42. The traffic emissions of NOx was reduced by up to 7%. Up to 20% reduction in traffic contribution to NOx concentrations was calculated as shown in Figure 1. The mean reduction in concentration for the whole area is 6% and the largest occur were most people live.The population weighted mean NOx concentration for 1.6 million people in Greater Stockholm is estimated to be reduced by 0.41 μg m-3. Assuming that the premature mortality is reduced by 8% per 10 μg m-3 (Nafstad et al., 2004), this corresponds to 42 avoided premature deaths every year or 514 gained life years gained. This is even somewhat more beneficial than the effects of the congestion charge in Stockholm (Johansson et al., 2009), which was estimated to save 27 premature deaths per year. The gain in reduced mortality is almost as large as the gain in health of the increased physical activity. Conclusions Transferring car commuters to bike is not only beneficial for the physical activity, but will also lead to reduced traffic emissions and reduced population exposure. Our estimates show that it may be even more beneficial for mortality due to air pollution exposure than the congestion charge in Stockholm. Acknowledgement This project was funded by the Swedish Research Council for Health, Working life and Welfare. References Johansson, C., Burman, L., Forsberg, B. 2009. The effects of congestions tax on air quality and health. Atmos. Environ. 43, 4843-4854.Nafstad, P., Lund Håheim, L., Wisloeff, T., Gram, G., Oftedal, B., Holme, I., Hjermann, I. and Leren, P. 2004. Urban Air Pollution and Mortality in a Cohort of Norwegian Men. Environ. Health Perspect. 112, 610-615.
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| 10. |
- Segerstedt, Bo, et al.
(författare)
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Health Effects from Road Dust
- 2006
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Ingår i: ISEE/ISEA 2006 Conference Abstracts Supplement. - Cambridge, MA : Blackwell Scientific Publications. ; , s. S233-
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Konferensbidrag (refereegranskat)abstract
- TAB3-PD-12 Whether coarse particles dominating road dust influence health or not is a question in the matter of measures of priority (remedial measures), among others. Within this project, we investigated how particulate matter (PM10), when characterized by high levels of road dust, affects daily mortality, acute hospital admissions, and emergency department visits in greater Stockholm. The study covered the period of 1994 to 2002. Daily hospital admissions and deaths were collected from registers maintained by the Centre for Epidemiology at the National Board of Health and Welfare. Records of acute visits at hospitals for asthma were obtained from Stockholm County Council. A total of 457 days characterized by high levels of road dust were identified using the 85th percentile for local non-exhaust PM10 time-series adjusted for rural background PM10 and urban levels of NOx representing local exhaust emissions. Data were analyzed and modelled with additative Poisson regression, following the strategy used in the APHEA project. In other words, smoothed functions for potential nonlinear relations with confounders are used in conjunction with linear terms, in order to achieve parameter estimates for the short-term effect of pollutants. The estimated effect of PM10 on asthma visits was 3.4% per 10 μg/m3for road dust days. With a 10.2 μg/m3 higher average urban background level of PM10(compared with days not classifed as road dust days), a mean of 20.5 daily respiratory admissions and a estimated coefficient of 0.0021 (0.00165), expressing a relative change of 2.1% per 10 μg/m3 PM10,roughly 200 respiratory hospital admissions were attributed to the road dust PM10 during the study period. There was no evidence that road dust affects hospital admissions for cardiovascular diseases. This might indicate that smaller, combustion-related particles are behind the connection betwen PM10 and acute cases of cardiac admissions that has been found even in Stockholm. The results of this study, as well as the epidemiologic litterature about mineral particles and the coarse fractions, gives evidence for road dust to increase respiratory problems and the acute visits, as well as hospital admissions for the matter.
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