Kilder til partikler i luften

Luftforurening er et resultat af emissioner (udledning), spredning i luften med vinden og evt. kemiske og fysiske omdannelser. Det er derfor ikke ligegyldigt, hvor og hvordan forureningerne emitteres. Lave kilder (f.eks. trafik og lokal boligopvarmning) giver anledning til høj lokal luftforurening og i byområder derfor til stor eksponering af befolkningen. Forureningen fra høje punktkilder (f.eks. kraftværker) fortyndes kraftigt, før den når jordoverfladen og giver derfor ikke med de danske regler for godkendelse af punktkilder anledning til væsentlig eksponering af befolkningen. Overalt findes der baggrundsforurening, der kan være transporteret over endog store afstande. Man kan derfor ikke slutte direkte fra emissioner til luftkvalitet. Endelig findes naturlige kilder til partikler i luften, f.eks. jordstøv, salt fra havet og skovbrande. En tværministeriel gruppe udarbejdede en redegørelse med henblik på at undersøge mulighederne og effekten af at fremme montering af filtre på dieselkøretøjer (Trafikministeriet, 2003). I Danmark er iværksat et 4-årigt projekt i Miljøministriet, udført af DMU 2001-2004. Det forventes, at der bl.a. under dette projekt opnås en større forståelse, end den der er i dag, af sammenhængen mellem disse partikler og helbredsskader. I det følgende er der givet en oversigt over partikelkilder, samt nogle resultater fra dette projekt (Palmgren et al. 2003)

Vejbelægningens indflydelse på partikelforureningen (PM10) på stærkt trafikerede gadestrækninger i Danmark

Luftbåren partikelforurening giver anledning til en betydelig mængde sundhedsskadelige effekter. Massen af partikler med diameter under 10 μm (PM10) har i København til og med 2008 ligget over EU’s grænseværdier for PM10. Fra 2008 til 2009 faldt årsmiddelværdien af PM10 med 6 μg/m3 på målestationen på H.C. Andersens Boulevard, København, således at grænseværdierne overholdes i 2009. Faldet skete forholdsvis brat efter august 2008, hvor der blev lagt ny belægning på H.C. Andersens Boulevard. Ændringerne i døgnvariationen af PM10 og grundstofsammensætningen i PM10 før og efter den nye belægning viser, at årsagen til det store fald skyldes en stor reduktion i de partikler, som hvirvles op fra vejen grundet trafikken. Vejbelægningen har dermed stor indflydelse på PM10 på stærkt trafikerede gadestrækninger. Der blev også set et mindre fald i PM2,5, men der kræves flere undersøgelser for at vurdere, hvor stor en del af dette fald, som skal tilskrives den nye belægning

Exposure to ambient concentrations of particulate air pollution does not influence vascular function or inflammatory pathways in young healthy individuals

<p>Abstract</p> <p>Background</p> <p>Particulate air pollution is associated with increased risk of cardiovascular events although the involved mechanisms are poorly understood. The objective of the present study was to investigate the effects of controlled exposure to ambient air fine and ultrafine particles on microvascular function and biomarkers related to inflammation, haemostasis and lipid and protein oxidation.</p> <p>Methods</p> <p>Twenty-nine subjects participated in a randomized, two-factor crossover study with or without biking exercise for 180 minutes and with 24 hour exposure to particle rich (number concentrations, NC: 11600 ± 5600 per cm³, mass concentrations: 13.8 ± 7.4 μg/m³and 10.5 ± 4.8 μg/m³for PM_10-2.5and PM_2.5, respectively) or particle filtered (NC: 555 ± 1053 per cm³) air collected above a busy street. Microvascular function was assessed non-invasively by measuring digital peripheral artery tone following arm ischemia. Biomarkers included haemoglobin, red blood cells, platelet count, coagulation factors, C-reactive protein, fibrinogen, interleukin-6, tumour necrosis factor α, lag time to copper-induced oxidation of plasma lipids and protein oxidation measured as 2-aminoadipic semialdehyde in plasma.</p> <p>Results</p> <p>No statistically significant differences were observed on microvascular function or the biomarkers after exposure to particle rich or particle filtered air.</p> <p>Conclusion</p> <p>This study indicates that exposure to air pollution particles at outdoor concentrations is not associated with detectable systemic inflammation, lipid or protein oxidation, altered haemostasis or microvascular function in young healthy participants.</p

Luftkvalitetsvurdering af miljøzoner i Danmark

Artiklen vurderer effekten for emissionen og luftkvaliteten af miljøzonereglerne, som kræver partikelfiltre på ældre tunge køretøjer i de største byer. Det sker gennem målinger og modelberegninger. Det er vanskeligt, at måle en effekt af de nye miljøzoner på partikelforureningen, da reduktionen er beskeden, og andre forhold spiller ind. Samme resultat viser modelberegninger. Modelberegninger er gennemført for koncentrationen af PM10, PM2.5 og NO2 for 138 undersøgte trafikerede gader. Beregninger viser, at miljøzonekravene vil reducere antallet af overskridelser af grænseværdien for NO2 i 2010 fra 65 gader ud af de 138 gader til 35 pga. miljøzonekravene

Betydningen af partikelfiltre for luftkvalitet og sundhedseffekter

Konsekvenser for emission, luftkvalitet, befolkningseksponering og sundhedseffekter af montering af partikelfiltre med en effektivitet på 80% på alle tunge dieselkøretøjer i Danmark er vurderet pba. eksisterende data. Sundhedsmæssige vurderinger er baseret på en metode udviklet af WHO, som tager udgangspunkt i PM10 i bybaggrundsluften. Beregningerne, der er behæftet med meget stor usikkerhed, viser at forureningen med PM10 kun reduceres lidt (skønsmæssigt omkring 2%) i byernes baggrunds- luft. Den beskedne reduktion skyldes, at en meget stor del af denne forurening er regional, d.v.s fra hele Europa, samt at dieselpartikler hovedsageligt er ultrafine med meget lav masse. De sundhedsmæssige gevinster bliver derfor tilsyneladende beskedne. Beregningerne med WHO’s metode resulterer således kun i en reduktion på 22 for tidligere dødsfald, som kunne spares ved montering af filtre. Imidlertid mistænkes de ultrafine partikler i dieselemission for at være ansvarlige for en væsentlig del af de partikelrelaterede helbredseffekter, og de ultrafine partikler reduceres med omkring 1/3 ved montering af filtre. Derfor må helbredseffekten antages at underestimeres ved den anvendte WHO metode

Model studies of dense water overflows in the Faroese Channels Topical Collection on the 5th International Workshop on Modelling the Ocean (IWMO) in Bergen, Norway 17-20 June 2013

The overflow of dense water from the Nordic Seas through the Faroese Channel system was investigated through combined laboratory experiments and numerical simulations using the Massachusetts Institute of Technology General Circulation Model. In the experimental study, a scaled, topographic representation of the Faroe-Shetland Channel, Wyville-Thomson Basin and Ridge and Faroe Bank Channel seabed bathymetry was constructed and mounted in a rotating tank. A series of parametric experiments was conducted using dye-tracing and drogue-tracking techniques to investigate deep-water overflow pathways and circulation patterns within the modelled region. In addition, the structure of the outflowing dense bottom water was investigated through density profiling along three cross-channel transects located in the Wyville-Thomson Basin and the converging, up-sloping approach to the Faroe Bank Channel. Results from the dye-tracing studies demonstrate a range of parametric conditions under which dense water overflow across the Wyville-Thomson Ridge is shown to occur, as defined by the Burger number, a non-dimensional length ratio and a dimensionless dense water volume flux parameter specified at the Faroe-Shetland Channel inlet boundary. Drogue-tracking measurements reveal the complex nature of flow paths and circulations generated in the modelled topography, particularly the development of a large anti-cyclonic gyre in the Wyville-Thompson Basin and up-sloping approach to the Faroe Bank Channel, which diverts the dense water outflow from the Faroese shelf towards the Wyville-Thomson Ridge, potentially promoting dense water spillage across the ridge itself. The presence of this circulation is also indicated by associated undulations in density isopycnals across the Wyville-Thomson Basin. Numerical simulations of parametric test cases for the main outflow pathways and density structure in a similarly-scaled Faroese Channels model domain indicate excellent qualitative agreement with the experimental observations and measurements. In addition, the comparisons show that strong temporal variability in the predicted outflow pathways and circulations have a strong influence in regulating the Faroe Bank Channel and Wyville-Thomson Ridge overflows, as well as in determining the overall response in the Faroese Channels to changes in the Faroe-Shetland Channel inlet boundary conditions. © 2014 Springer-Verlag Berlin Heidelberg

Receptor Modeling Source Apportionment of PM10 and Benzo(a)pyrene in Krakow, Poland

The main energy source in Krakow, Poland is coal combustion, which is believed to be the reason for frequent winter episodes of extremely high ambient air concentrations of particulate matter (PM10) and associated benzo(a)pyrene B(a)P. Results are presented on the source apportionment of PM10 and B(a)P during two episodes of thermal inversion (14/1 ; 2/3, 2005) at four different air monitoring stations and four apartments (indoor) in the city of Krakow, The results are compared to the Zakopane mountain site selected due to its prominent domestic coal heating and little traffic. The source apportionment was based on receptor modeling of the total of 72 ambient PM samples and 21 individual PM sources, chemically characterised for a high number of organic and inorganic compounds including polyaromatics (15 PAH and 18 azaarenes) heavy metals and trace elements (28 compounds), major ions, soot and organic carbon. An array of multivariate receptor models was used i.e. chemical mass balance (CMB), constrained matrix factorisation (CMF), constrained physical receptor modelling (COPREM) positive matrix factorization (PMF), principle component analysis with multi-linear regression analysis (PCA-MLRA), edge analysis (UNMIX), cluster analysis (CA), and self organizing maps SOM). The variation in the receptor dataset (55 compounds, 60 outdoor and 12 indoor PM samples) allowed the models of the pure factor analysis type (PMF, UNMIX, PCA-MLRA) to identify 3-5 factors of mixed sources. The interpretation of the factors was not straightforward, but pointed to a dominating primary source contribution from coal combustion (>60%) and a minor contribution from traffic (<10%). The secondary PM sources (20-30%) comprised industry and traffic. The results of cluster analysis and self organizing maps supported these indications. PMF was able to disaggregate the coal combustion into three factors i.e. ~10% related to industrial activities, ~20% related to home heating by stoves (coal) and ~30% related to boilers. The chemical fingerprints of the receptor samples and the main PM sources in Krakow and Zakopane allowed the pure chemical mass balance; type model (EPA-CMB8.2) to estimate the major contributions from two primary source types i.e. residential heating by coal combustion in small stoves and low efficiency boilers (~45%) and boilers with rudimentary PM reductions techniques such as cyclones (~15%), one major secondary source deriving from industrial and traffic emissions of SO2 + NOx + possibly HCl (~20%). Five minor primary sources were also identified i.e. traffic 5%, biomass burning ~5%, coke/fuel combustion ~5%, industrial high efficiency coal combustion 3%, and road/salt/rock re-suspension ~2%. The indoor PM10 and B(a)P were found to have the same sources as outdoor PM10 and B(a)P The results obtained by the models CMF and COPREM - which are hybrids of factor analysis and chemical mass balance generally agreed with the CMB results. However, their source contribution estimates are slightly different: residential heating ~30%, boilers with rudimentary PM reductions techniques such as cyclones ~30%, industrial high efficiency coal combustion ~15% traffic 3-7%, secondary 13-21%, road/salt/rock re-suspension 2-8%. All receptor models calculated residential heating to be the principal PM source in Zakopane (70-80%).JRC.H.4-Transport and air qualit