| 1. |
- Johansson, Christer, et al.
(författare)
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Impacts of air pollution and health by changing commuting from car to bicycle
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 584-585, s. 55-63
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Tidskriftsartikel (refereegranskat)abstract
- Our study is based on individual data on people’s home and work addresses, as well as their age, sex and physical capacity, in order to establish realistic bicycle-travel distances. A transport model is used to single out data on commuting preferences in the County Stockholm. Our analysis shows there is a very large potential for reducing emissions and exposure if all car drivers living within a distance corresponding to a maximum of a 30 minute bicycle ride to work would change to commuting by bicycle. It would result in more than 111 000 new cyclists, corresponding to an increase of 209% compared to the current situation.Mean population exposure would be reduced by about 7% for both NOx and black carbon (BC) in the most densely populated area of the inner city of Stockholm. Applying a relative risk for NOx of 8% decrease in all-cause mortality associated with a 10 µg m-3 decrease in NOx, this corresponds to more than 449 (95% CI: 340 - 558) years of life saved annually for the Stockholm county area with 2.1 million inhabitants. This is more than double the effect of the reduced mortality estimated for the introduction of congestion charge in Stockholm in 2006. Using NO2 or BC as indicator of health impacts, we obtain 395 (95% CI: 172 - 617) and 185 (95% CI: 158 - 209) years of life saved for the population, respectively. The calculated exposure of BC and its corresponding impacts on mortality are likely underestimated. With this in mind the estimates using NOx, NO2 and BC show quite similar health impacts considering the 95% confidence intervals.
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| 2. |
- Krecl, Patricia, et al.
(författare)
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A feasibility study of mapping light-absorbing carbon using a taxi fleet as a mobile platform
- 2014
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Ingår i: Tellus. Series B, Chemical and physical meteorology. - : Stockholm University Press. - 0280-6509 .- 1600-0889. ; 66, s. 23533-
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-containing particles are associated with adverse health effects, and their light-absorbing fractions were recently estimated to be the second largest contributor to global warming after carbon dioxide. Knowledge on the spatiotemporal variability of light-absorbing carbon (LAC) particles in urban areas is relevant for air quality management and to better diagnose the population exposure to these particles. This work reports on the first mobile LAC mass concentrations (M-LAC) measured on-board four taxis in the Stockholm metropolitan area in November 2011. On average, concentrations were higher and more variable during daytime (median of 1.9 mu g m(-3) and median absolute deviation of 2.3 mu g m(-3)). Night-time (21:00-05:00) measurements were very similar for all road types and also compared to levels monitored at an urban background fixed site (median of 0.9 mu g m(-3)). We observed a large intra-urban variability in concentrations, with maxima levels inside road tunnels (median and 95th percentile of 7.5 and 40.1 mu g m(-3), respectively). Highways presented the second ranked concentrations (median and 95th percentile of 3.2 and 9.7 mu g m(-3), respectively) associated with highest vehicle speed (median of 65 km h(-1)), traffic rates (median of 62 000 vehicles day(-1) and 1500 vehicles h(-1)) and diesel vehicles share (7-10%) when compared to main roads, canyon streets, and local roads. Multiple regression modelling identified hourly traffic rate and M-LAC concentration measured at an urban background site as the best predictors of on-road concentrations, but explained only 25% of the observed variability. This feasibility study proved to be a time-and cost-effective approach to map out ambient M-LAC concentrations in Stockholm and more research is required to represent the distribution in other periods of the year. Simultaneous monitoring of other pollutants, closely correlated to M-LAC levels in traffic-polluted environments, and including video recording of road and traffic changes would be an asset.
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| 3. |
- 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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| 4. |
- Nerhagen, Lena, et al.
(författare)
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Luftföroreningarnas externa kostnader : förslag på beräkningsmetod för trafiken utifrån granskning av ExternE-beräkningar för Stockholm och Sverige
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In 2002 the external costs of air pollution from the Swedish transport sector were calculated using the methodology developed within the EU-funded ExternE-projects. A comparison of these estimates with those presently in use in Swedish transport analysis revealed important differences, especially for particulate matter. The main purpose of this project was to examine the calculations for Stockholm in the Swedish ExternE-study and based on the findings from this examination propose a method to be used for the cost calculation for pollutants with local impacts. In addition, the methods used for the cost calculation for pollutants with regional impact should be described. In the report, the results are presented in two parts. In the first part, the method we propose for the cost calculation for pollutants with local impact is presented. We suggest that the calculation is based on three components; exposure estimates, effects estimates and values. The product of these three gives the final cost. In this part of the report we also present the approaches currently used to calculate the cost for pollutants with a regional impact. In part two of the report we present in greater detail the findings from the examination of the calculations for Stockholm in the Swedish ExternE-study.
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| 5. |
- Nilsson Sommar, Johan, et al.
(författare)
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Potential Effects on Travelers' Air Pollution Exposure and Associated Mortality Estimated for a Mode Shift from Car to Bicycle Commuting
- 2020
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 17:20
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Tidskriftsartikel (refereegranskat)abstract
- This study aims to use dispersion-modeled concentrations of nitrogen oxides (NOx) and black carbon (BC) to estimate bicyclist exposures along a network of roads and bicycle paths. Such modeling was also performed in a scenario with increased bicycling. Accumulated concentrations between home and work were thereafter calculated for both bicyclists and drivers of cars. A transport model was used to estimate traffic volumes and current commuting preferences in Stockholm County. The study used individuals' home and work addresses, their age, sex, and an empirical model estimate of their expected physical capacity in order to establish realistic bicycle travel distances. If car commuters with estimated physical capacity to bicycle to their workplace within 30 min changed their mode of transport to bicycle, >110,000 additional bicyclists would be achieved. Time-weighted mean concentrations along paths were, among current bicyclists, reduced from 25.8 to 24.2 mu g/m(3) for NOx and 1.14 to 1.08 mu g/m(3) for BC. Among the additional bicyclists, the yearly mean NOx dose from commuting increased from 0.08 to 1.03 mu g/m(3). This would be expected to yearly cause 0.10 fewer deaths for current bicycling levels and 1.7 more deaths for additional bicycling. This increased air pollution impact is much smaller than the decrease in the total population.
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| 6. |
- Orru, Hans, et al.
(författare)
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Estimated health impacts of changes in air pollution exposure associated with the planned by-pass Förbifart Stockholm
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- För att minska problem med trängsel på vägnätet i Stockholm och möta framtida transportbehov planeras en 21 km lång förbifart i nord-sydlig sträckning, varav cirka 18 km skulle gå i tunnel. Denna nya led, Förbifart Stockholm, förväntas förbättra luftkvaliteten i områdets central delar som avlastas trafik på ytvägar, samtidigt kommer de som färdas I tunnel att kunna utsättas för höga koncentrationer av trafikföroreningar.Trafikföroreningarna utgörs dels av motoravgaser med avgaspartiklar (bl a dieselsot), kolväten och kväveoxider (NOX) som viktiga komponenter. Dessa föroreningar brukar studeras som indikatorer på hur farlig luften är, I synnerhet NO2 och NOX. I tunnelmiljö är NOX (NO + NO2) en bättre indikator än NO2 på hur hög avgashalten är i jämförelse med i utomhusluft och hälsostudier, eftersom NO inte oxideras till NO2 i samma utsträckning som i utomhusluft.Förutom avgaser består trafikföroreningarna av slitagepartiklar från vägbanor och fordon (främst däck och bromsar). Dessa partiklar ingår i det man brukar kalla vägdamm, vilket består av större partiklar än avgaserna. För vägdamm kan masskoncentrationen (vikt/volym luft) av PM10 (partiklar mindre än 10 mikrometer) användas som ett relevant mått på koncentrationen. För de mycket mindre avgaspartiklarna används inte så ofta masskoncentrationen i luft. Hur höga halter det skulle bli i tunnelmiljön beror förutom på utsläppens omfattning på ventilationslösningarna, varför beräknade förhållanden blir mer osäkra. För tunnelhalterna är det dessutom svårare att uppskatta antal exponerade personer och avskiljningen som fordonskupen ger. Beräkningarna för hur utomhusluften påverkas är förenade med mindre osäkerhet.Skillnaderna i befolkningsexponering via ändrade årsmedelhalter i omgivningsluften har beräknats för NOX och PM10 med en spridningsmodell och upplösningen 100x100 m, vilket sedan kopplats till befolkningen vid årsskiftet 2011/12 (1 628 528 invånare) med samma geografiska upplösning.Exponeringstillskottet från nyttjandet av tunnel har beräknats utifrån förväntat antal fordon, antal personer i fordonen, halten längs olika sträckor samt restiden längs olika sträckor. Som indikator på avgaser används NOX eftersom det finns kända dos-responssamband för viktiga effekter som inverkan på dödlighet. För vägdamm används PM10 som mått på halterna. Innan förändringen i hälsokonsekvenser beräknas för antalet personer som förväntas nyttja tunneln, dras ifrån den lägre exponering som skulle erhållas vid motsvarande resor på ytvägnätet.Hälsokonsekvenserna av förändrad exponering har beräknats med etablerade metoder och beräkningsprogrammet AirQ utvecklat av WHO. För dessa beräkningar har relevanta exponerings-responsantaganden eftersträvats. För avgasernas effekt på dödlighet har vi hämtat sambandet från en studie genomförd i Oslo, med en relative ökning på 8% per 10 μgm-3 i NOX, och för vägdamm från en studie genomförd i Stockholm där dagligt antal dödsfall ökade 1.68% per 10 μgm-3 högre halt av PM10. För beräkningarna av tunnelexponeringens betydelse för förtida dödsfall har antagandena om de exponerades åldersfördelning stor betydelse, eftersom en relativ riskökning får större konsekvenser ju högre risken är från början. Ur ett biologiskt perspektiv kan man se det som att äldre är mer känsliga för exponeringen exempelvis för att deras lungor och hjärtan inte är lika friska som hos yngre.Beräkningarna visar att för befolkningen skulle förbifarten minska antalet förtida dödsfall med 23,7 (95% CI 17.7–32.3) per år, huvudsakligen genom lägre exponering för avgaser. Minskad exponering för vägdamm står bara för 0,5 fall per år färre. Andra former av ohälsa beräknas också minska något till följd av lägre halter. Samtidigt skulle exponeringstillskottet som tunnelluften ger jämfört med resa på ytvägnätet bland annat leda till förtida dödsfall. Under rusningstid skulle avgashalterna i tunneln mätt som NOX nå närmare 2000 μgm-3. Att passera hela tunneln skulle två gånger om dagen, 5 dagar i veckan, under rusningstid, skulle ge ett tillskott till årsmedelexponeringen motsvarande 9.6 μgm-3 NOX. Om man antar ett genomsnitt på drygt 55 000 fordon per dygn vardera riktning och 1.3 person per fordon, fördelade som åldersgruppen 30–74 år, förväntas en årlig ökning av antalet förtida dödsfall om 20,6 (95% CI 14.1–25.6). Skulle det bli fler personer per fordon eller en högre andel känsliga t ex på grund av äldre resenärer, blir resultatet av exponeringen fler förtida dödsfall. De verkliga effekterna skulle alltså kunna bli annorlunda därför att scenarierna vi antagit inte stämmer.
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| 7. |
- Orru, Hans, et al.
(författare)
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Potential health impacts of changes in air pollution exposure associated with moving traffic into a road tunnel
- 2015
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Ingår i: Journal of Exposure Science and Environmental Epidemiology. - : Springer Science and Business Media LLC. - 1559-0631 .- 1559-064X. ; 25:5, s. 524-531
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Tidskriftsartikel (refereegranskat)abstract
- A planned 21 km bypass (18 km within a tunnel) in Stockholm is expected to reduce ambient air exposure to traffic emissions, but same time tunnel users could be exposed to high concentrations of pollutants. For the health impacts calculations in 2030, the change in annual ambient NOX and PM10 exposure of the general population was modelled in 100 x 100 m(2) grids for Greater Stockholm area. The tunnel exposure was estimated based on calculated annual average NOX concentrations, time spent in tunnel and number of tunnel users. For the general population, we estimate annually 23.7 (95% Cl: 17.7-32.3) fewer premature deaths as ambient concentrations are reduced. At the same time, tunnel users will be exposed to NOX levels up to 2000 mu g/m(-3). Passing through the whole tunnel two times on working days would correspond to an additional annual NOX exposure of 9.6 mu g/m(3). Assuming that there will be similar to 55,000 vehicles daily each way and 1.3 persons of 30-74 years of age in each vehicle, we estimate the tunnel exposure to result in 20.6 (95% Cl: 14.1-25.6) premature deaths annually. If there were more persons per vehicle, or older and vulnerable people travelling, or tunnel dispersion conditions worsen, the adverse effect would become larger.
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