Impact on local air quality of the Danish landworks in the fixed link across Øresund.

The combined bridge and tunnel link between Sweden and Denmark (the Øresund Link) and the related land constructions are expected to be in operation around the turn of the century. This new link across the Øresund and the island Amager may result in significant changes in traffic pattern and traffic intensity - and therefore changes in air quality in some areas can not be excluded. An investigation initiated in 1994 on the Danish side of the link comprises monitoring of present air pollution at the Airport Motorway and model evaluations of future pollution levels at the motorway and in six street canyons. For all locations the pollution levels are calculated for the present situation and for scenarios for the years 2000 and 2010 both with and without the fixed link. For the future scenarios an expected development of vehicle technology is taken into account. It appears that the general air quality in the area will not be worsen. Only for benzene there is a continued risk of violation of limit values; this may however be changed by planned emission restrictions.A special situation however, may arise near the apartment buildings "Vinkelhusene". Here it has been decided to cover about 700 m of the motorway, in order to reduce noise and to avoid a barrier effect. This will result in increased pollution levels near the tunnel exits.All calculations are performed with dispersion models developed at the National Environmental Research Institute and are based on traffic scenarios from a traffic model developed by Anders Nyvig Ltd

Brugervenlig udgave af gadeluftkvalitetsmodellen OSPM

En Windows brugerflade er under udvikling til gadeluftkvalitetsmodellen Operational Street Pollution Model (OSPM), således at den let kan bruges af kommuner, amter og konsulentfirmaer i forbindelse med vurdering af luftkvaliteten i byer. I tilknytning til udarbejdelse af brugerfladen er der opstillet standardværdier for trafikkens variation, trafikemission, samt meteorologi og bybaggrundsforureningen, således at brugeren med få indgangsparametre og valg blandt standardværdier kan gennemføre luftkvalitetsberegninger

Fremtidig luftkvalitet i danske byer - effekter af skærpede emissionsnormer

Omfattende beregninger med en række luftkvalitetsmodeller udviklet af Danmarks Miljøundersøgelser viser, at den regionale baggrundsforurening uden for byerne, bybaggrundsforureningen over byerne og luftkvaliteten i gadeniveau bliver bedre i fremtiden. Dette skyldes især EU’s skærpede regulering af køretøjers emission. EU’s nye grænseværdier for kvælstofdioxid (NO2), kulilte (CO) og benzen gældende for 2010 forventes ikke at blive overskredet. Ozonniveauerne forventes at stige lidt, fordi begrænsningen i bilernes emission af kvælstofmonoxid (NO) betyder, at mindre ozon fjernes i reaktioner med NO i dannelsen af NO2. Det er endnu ikke muligt at modellere partikler. Ud fra foreløbige vurderinger er der usikkerhed om, hvorvidt EU’s grænseværdi for partikler kan overholdes i 2010. Grænseværdierne er opstillet for at beskytte befolkningens sundhed

VALIDATION OF AIRGIS - A GIS-BASED AIR POLLUTION AND HUMAN EXPOSURE MODELLING SYSTEM

This study describes in brief the latest extensions of the AirGIS system used in Denmark for exposure modelling and gives results of a validation with measured air pollution data. The system shows a good performance for both long term averages (annual and monthly averages) as well as short term averages (hourly and daily)

Virkemidler til overholdelse af NO2 grænseværdier for luftkvalitet i København

Projektet beskriver kilderne til NO2 på H.C. Andersens Boulevard, Jagtvej og andre stærkt trafikerede gader i Københavns Kommune, og der er foretaget en systematisk kortlægning af omfanget af problemet med høje NO2-niveauer i byen. Der opstilles fire forskellige teknologiske og trafikale scenarier, som er vurderet med hensyn til deres effekt på trafikken og NO2-niveauerne. Det første scenarie sigter på, hvad kommunen kan gøre med virkemidler der ligger i kommunens regi. Det andet belyser, hvor langt man kommer ved at reducere bilkørsel ved at indføre forskellige former for afgifter (betalingsring/kørselsafgifter). Det tredje scenarie ser på, hvor langt man kommer ved at udnytte den reneste teknologi i køretøjsparken. Det fjerde scenarie sammenfatter alle typer af virkemidler og belyser den maksimale effekt. Det vurderes også, hvordan virkemidlerne kan implementeres mht. ansvarlige parter, offentlige omkostninger og tidshorisont. Endelig foretages en særskilt overordnet vurdering af scenariernes betydning for PM10 (partikler under 10 mikrometer), idet der knytter sig større usikkerheder til det eksisterende videngrundlag for partikler end for NO2. Emissionsberegninger viser, at der kan forventes en reduktion i trafikkens NOx emission på ca. 20% fra 2003 til 2010 i København ud fra allerede vedtagne emissionsnormer for køretøjer, men at den skal reduceres yderligere med 25-55% for, at NO2 grænseværdien kan overholdes i 2010. Luftkvalitetsberegninger viser, at overskridelser af grænseværdien for NO2 i 2010 vil forekomme langs en række stærkt trafikerede gader i København (80 ud af 138 undersøgte gadestrækninger). Dette kan kun imødegås med indførelse af nye skærpede EU emissionsnormer for især de tunge og lette dieselkøretøjer, som skal være så strenge at NOx begrænsende udstyr anvendes på begge grupper af dieselkøretøjer. Da nye emissionsnormer kun vil gælde nye køretøjer vil det tage lang tid at opnå den fulde effekt for luftkvaliteten, da køretøjsparken udskiftes langsomt. Det er derfor nødvendigt at kombinere nye emissionnormer med en miljøzone for København for at fremme en hurtigere implementeringen. Det vurderes dog, at en implementering af virkemidler, så grænseværdien kan overholdes i 2010, næppe tidsmæssigt kan nås. Andre trafikale virkemidler som infrastruktur, pendlerplaner, trafiksanering, betalingsring eller road-pricing vil kun have begrænset effekt på luftkvaliteten, da den trafikale effekt er begrænset. For PM10 vil tiltagene kun have begrænset effekt, idet bidraget fra udstødningen til den samlede partikelforurening er lille i forhold til bidrag fra bybaggrunden og bidrag fra vejslid, jordstøv og bremser. PM10 grænseværdien for 2005 forventes kun overskredet på få strækninger

TOOL FOR EXPLORATORY ANALYSIS OF OSPM MODEL PERFORMANCE FOR LONG TIME SERIES

Abstract: The Danish Operational Street Pollution Model, OSPM, has for two decades been successfully applied in many cities worldwide as recently reviewed by Key words: model validation, street canyon, urban air pollution, OSPM, exploratory data analysis. INTRODUCTION The OSPM (Operational Street Pollution Model) has been evaluated and applied by a wide range of users worldwide (see: Kakosimos et al. 2010) for modelling urban air pollution at street level. Proper model validation protocols and best modelling practise have been discussed in the scientific community for many years, lately in the COST 732 action (URL 1) and in the Forum for Air quality Modelling in Europe (FAIRMODE, URL 2). A document produced by COST 732 provides general guidance on model evaluation protocols (Britter and Schatzmann, 2007). Model validation is also relevant in context of the European Air Quality Directive (EC, 2008) that is mentioning models as a method to assess air quality with respect to compliance with limit values. The directive defines some model quality objectives that are now interpreted and discussed within FAIRMODE, and performed tests have revealed some ambiguities in the interpretation of those objectives (e.g. Gidhagen at al. 2011). This paper aims at contributing to the discussion. Model quality objectives are in the directive as in other guidelines formulated in terms of quantitative statistical analysis, e.g. maximum uncertainty presented for the annual average or for percentiles. However this statistical analysis might obscure deficiencies of the model, and model results could be "right for the wrong reason", i.e. the model quality objective might be fulfilled even if the model fails to reproduce some essential features in observations. Therefore Di Sabatini et al. (2008) recommended for the case of CFD models a combination of qualitative (exploratory data analysis) and quantitative (statistical analysis) evaluations. The usefulness in identifying model errors by means of qualitative data analysis using an automated Excel workbook was presented by Olesen et al. (2008). This work focuses on the evaluation of OSPM and presents a similar approach suggesting a combined evaluation strategy of qualitative and quantitative analysis. Even though OSPM is a parameterised semi-empirical model with much simpler physics compared to the CFD models this evaluation strategy is applicable. This approach and the here presented Excel evaluation tool can easily be used also by other models of this type

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

A MODEL EVALUATION PROTOCOL FOR URBAN SCALE FLOW AND DISPERSION MODELS

This paper reports on a comprehensive model evaluation protocol for urban scale flow and dispersion models that has been developed within the framework of the COST action 732 on Quality Assurance and Improvement of Micro-Scale Meteorological Models. It briefly discusses the different components forming model evaluation with particular emphasis on model validation and on the implementation of the protocol for a specific test case: the MUST (Mock Urban Setting Test) experiment. The protocol was first developed with building-resolving models in mind, but more traditional integral models have also been included. Currently the Action is finalising the MUST exercise results and will suggest the best approach for further model evaluation and for the standardization of CFD modelling practise for micro-scale meteorological applications

EVALUATION AND INTER-COMPARISON OF OPEN ROAD LINE SOURCE MODELS CURRENTLY IN USE IN THE NORDIC COUNTRIES

The aim of this study is to inter-compare and evaluate operational open road Gaussian line source models currently in use in the Nordic countries Norway, Denmark and Finland. By comparing the models and their results on different datasets, a more robust and objective assessment of model performance and applicability can be made. Four models, HIWAY2-AQ, OML-Highway, CAR-FM1 and WORM, are applied to datasets from three measurement campaigns from each of the mentioned countries. A more specific target is to determine the conditions under which the models perform well or poorly in order to focus attention on these aspects in future model development. The various models arc evaluated primarily with regard to wind speed, wind direction and atmospheric stability in order to identify problem areas. Generally, the correlation between model estimates and observations decreases when normalising with emissions, due to the significant positive correlation between observed concentrations and emissions. Furthermore, we found a reduction of bias when normalising the Norwegian and Danish data, caused by overestimation of the dispersion at lower emission values. This occurs because the initial dispersion is too large in all the models. For higher emissions at the Danish site, the relative bias was higher, compared with the relative bias at the Norwegian site, indicating the influence of traffic density and vehicle speed (which arc both largest at the Danish site) on traffic produced turbulence and model performance. OML-Highway, however, performs best in this regard due to its more advanced parameterisation of traffic produced turbulence based on production and decay of turbulent kinetic energy. With regard to horizontal profiles, RB for CAR-FMI increased as function of distance from the road, indicating that the Lagrangian time scales are too short