Gunnar Omstedt

Evaluation of new model tools for meeting the targets of the EU Air Quality Directive: a case study on the studded tyre use in Sweden

Two new model tools have been developed for meeting the EU Air Quality Directive targets: SIMAIRroad (related to traffic emissions) and SIMAIRrwc (rwc standing for residential wood combustion). The models have been evaluated for different traffic situations and for residential areas with wood combustion, with promising results. The models can calculate PM10 statistics, such as mean values and 90 and 98 percentiles, that are well within ±50%. In fact, most of the results are within ±25%. Studded tyres are one important factor causing high PM10 concentrations in Swedish streets, so reducing their use would considerably improve air quality.

High-resolution modeling of residential outdoor particulate levels in Sweden.

Large-scale exposure assessments that include both between- and within-city differences in air pollution levels are lacking. The objective of this study was to model long-term particle exposure for the whole of Sweden, separating long-range transport from local sources, which were further separated into combustion and road dust. Annual regional, urban and local traffic PM exposure contributions were modeled for 26,000 addresses from a national survey, using a European scale model, an urban model and a local traffic model. Total PM10 was overall dominated by the regional contribution, ranging from 3.5 μg/m3 (northernmost) to 13.5 μg/m3 (southernmost). Local traffic and urban sources contributed nationally on average to 16% of total PM10, but for urban populations this contribution was larger (for Stockholm around 30%). Generalized to the Swedish adult population, the average residential exposure contributions from regional, urban and local traffic PM10 were 10.2, 1.3 and 0.2 μg/m3, respectively. Corresponding exposure to PM1 was 5.1, 0.5 and 0.03 μg/m3, respectively. Long-range transport dominates average Swedish residential PM1 and PM10 levels, but for urban populations the contributions from urban and local traffic sources are important and may even dominate for residences close to heavily trafficked roads. The study shows the importance of considering both national and city-scale gradients. The approach to exposure modeling at home addresses of a Swedish cohort includes both the regional scale and the urban and local traffic contributions to total PM exposure. With this we can resolve both between- and within-city gradients in national exposure assessments. The within-city exposure is further divided into a submicron (combustion) and a supermicron (road dust generated by studded tires) part. This gives new possibilities to study health impacts of different particles generated in Scandinavian cities.

Long-term continuous measurements of air pollutant concentrations, meteorology and traffic on a rural motorway and a model validation

Abstract Air concentrations of carbon monoxide (CO), nitrogen oxide (NO) and nitrogen dioxide (NO 2 ) were continuously monitored at a rural motorway site in Sweden for the period February–December 1990. In addition, local meteorology and traffic parameters were measured in order to validate a dispersion model. Even close to the motorway, the concentrations of CO and NO 2 were well below Swedish air quality guidelines. For long-term averages the regional background contributed significantly to the downwind levels. The atmospheric reaction between primary emitted NO and background ozone (O 3 ) tends to be a major source of downwind NO 2 , also fairly close to the road (10 m from the road shoulder), where the average NO 2 /NO x ratio was approximately 0.4. The validated model employs a percentile analysis on the basis of the HIWAY-2 and CALINE4 models and a separate emission model. The agreement between measured and modelled data, as refered to the 98th percentile, was good for NO 2 but moderate for CO. This is probably partly caused by uncertainties in emission factors for CO for heavy vehicles. Since a good agreement was observed between measured and calculated NO x concentrations, problems in adequately modelling NO 2 are probably associated with uncertainties as to NO 2 /NO x ratios in the exhaust, or the modelling of the O 3 reaction.

Health Impact of PM10, PM2.5 and Black Carbon Exposure Due to Different Source Sectors in Stockholm, Gothenburg and Umea, Sweden

The most important anthropogenic sources of primary particulate matter (PM) in ambient air in Europe are exhaust and non-exhaust emissions from road traffic and combustion of solid biomass. There is convincing evidence that PM, almost regardless of source, has detrimental health effects. An important issue in health impact assessments is what metric, indicator and exposure-response function to use for different types of PM. The aim of this study is to describe sectorial contributions to PM exposure and related premature mortality for three Swedish cities: Gothenburg, Stockholm and Umea. Exposure is calculated with high spatial resolution using atmospheric dispersion models. Attributed premature mortality is calculated separately for the main local sources and the contribution from long-range transport (LRT), applying different relative risks. In general, the main part of the exposure is due to LRT, while for black carbon, the local sources are equally or more important. The major part of the premature deaths is in our assessment related to local emissions, with road traffic and residential wood combustion having the largest impact. This emphasizes the importance to resolve within-city concentration gradients when assessing exposure. It also implies that control actions on local PM emissions have a strong potential in abatement strategies.

Risk of Air Pollution in Relation to Cancer in the Nordic Countries

Seventeen pollutants (particles, heavy metals, inorganic gasses and organic compounds) are for the first time analyzed in a screening of the carcinogenic risk at very high resolution and large scal ...

Exposure Modeling of Traffic and Wood Combustion Emissions in Northern Sweden

Traffic and residential wood combustion (rwc) constitute the two dominating local sources to fine particulate matter PM2.5 concentration levels in Sweden. In order to meet the authorities’ requirements of air quality assessments, a national modelling system SIMAIR has been developed. The system is based on the commercial Airviro air quality management software, a three tier client/server/web system which includes modules for measurement data collection, emission databases and dispersion models with very high performance in terms of data access and model execution. The technical characteristics of Airviro databases and models have facilitated web based national air quality systems, of which some examples are given.

Emissions and air exposure of carcinogens and co-carcinogens in four Nordic countries

This project (KoL 12-08) was performed for the Climate and Air Quality Group (KlimaogLuftgruppen, KoL), Nordic Council of Ministers by atmospheric emission, exposureand epidemiology experts from De ...

Estimation of trends in urban traffic NOx emissions by an empirical model

A model has been developed to estimate trends in urban traffic NOx emissions by measured NO2 concentrations.