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English summary and conclusionsSummary of the situation in Copenhagen and existing knowledge
The present report is a short summary of the particulate air pollution investigations in Copenhagen and a short summary of the state of the art. The measurements included mainly Total Suspended Particulates (TSP) and black smoke until the late 1990's. They showed a significantly
decreasing trend at all monitoring stations in Denmark, except at H.C. Andersens Boulevard in Copenhagen, a busy street in the city centre, where the concentration of TSP has been nearly constant since 1990.
Properties and health effects of particles
Within the last 10 years it has been realised that other parameters than total mass of the particles are more important in relation to health effects. Especially the sizes of the particles are important, but also the physical and chemical properties seem to play an important role. Many activities have been initiated internationally on investigations of the properties of the particles and the relationship with health effects.
New types of measurements
Measurements of PM10 and PM2.5 (particles with a diameter below 10 and 2.5 µm, respectively) are now included in the air quality monitoring programmes in USA and the EU. Within the EU, a review of the limit values is under consideration in order to define more health relevant particle parameters, i.e. particle number, PM1 or others.
Danish investigations
PM10 has been measured the last few years in the Danish Air Quality Monitoring Programme (LMP IV) and the air quality monitoring carried out by Copenhagen Environmental Protection Agency (CEPA). PM2.5 measurements have been carried out in Copenhagen in periods since 2002. In addition, National Environmental Research Institute (NERI) has a four-year particle research project and has in a cooperation with CEPA initiated measurements of ultrafine particles in Copenhagen.
Data from Copenhagen
The analysis of existing data from Copenhagen has shown that the most important contribution to PM10 in urban background is long range transported primary and secondary particles (> 90%). The contribution from traffic at busy streets in central Copenhagen, e.g. H.C. Andersens Boulevard (> 60,000 vehicles per day) and Jagtvej (> 22,000 vehicles per day) is significant (> 30%). More than 50% of the traffic contribution is coarse particles, e.g. from road dust and wear of
road surface, tires, brakes etc. However, it is not clear, what the health impact of these coarse particles is. The monitoring station at H.C. Andersens Boulevard is the most PM10 exposed site in Copenhagen. The contribution from traffic to fine particles (PM2.5) has been estimated to approx. 13%, and the contribution to coarse particles (PM10 - PM2.5) has been estimated to approx. 32%.
Indoor pollution
People spend most of their time indoor, where the particle concentration is highly influenced by indoor sources, e.g. cooking, smoking etc. Preliminary studies in Copenhagen indicate that the indoor particle concentrations in apartments without indoor sources are more or less like the urban background concentrations, even in apartments facing busy streets. However, it is recommended in any case to get fresh air in the apartments from the backyard side of the buildings.
Exceedance of EU limit values
The Danish (EU) air quality limit values, which the Member States have to comply with in 2005, are exceeded at some locations. The particulate pollution could probably be reduced to levels below the limit value, if all fine (exhaust) particles from the road traffic could be
removed. A larger reduction could be obtained, if the non-exhaust particles be removed, especially from heavy traffic. However, it would not be possible (by Danish measures alone) to comply with the proposed limit values for 2010, because the long range transported
contribution is larger (ca. 22 µg/m3) than the proposed limit value for the annual average (20 µg/m3). This part of the particulate pollution has to be reduced in a European co-operation, e.g. by reduced emissions of particles as well as gases, which lead to formation of secondary particles. Stronger requirements on reduced emissions from vehicles in the next few years are already adopted in EU, but it is still uncertain whether they are sufficient in relation to the proposed limit values for 2010.
Ultrafine particles are the most hazardous
The ultrafine particles from road traffic seem to be the most hazardous. A large fraction is emitted as exhaust from engines, especially from diesel engines. Efficient filters or other technical solutions can remove a major part of these particles.
Health effects
Several assessment studies of mortality and premature death have been carried out in Denmark, especially in Copenhagen. The assessments were carried out by the Health Inspector of Copenhagen, the Danish Environmental Protection Agency and specifically in relation to the particles from heavy traffic by a group chaired by the Danish Traffic Agency. All the investigations showed a significant impact of the particulate pollution from traffic, i.e. a few hundreds extra premature deaths per year. However, the uncertainties are still very high.
More measurements and research needed
Ongoing applied research aims at a better knowledge about the particulate pollution (including emission factors), especially in order to include particles in the air quality models for analysis, planning, scenario calculations and short-term forecasts. It is important to continue and strengthen this and co-ordinate investigations with health studies. The studies in Copenhagen contribute to this research and should be continued. The exposure of the population is highest in Copenhagen, especially from the traffic. The investigations in relation to health effects were mainly carried out based on rather unspecific air pollution parameters (TSP, PM10 or black smoke). Future research should include continuous measurements of parameters, which can be related directly to adverse health effects. The present studies in Copenhagen are important supplements to this type of research.
Danish investigations
The Ministry of the Environment has initiated a research programme on particles. The programme includes several activities, i.e. characterisation of atmospheric particles, particle sources, technical measures, health effects and socio-economic assessments. The programme
will run until the end of 2004 and will create an improved basis for assessment of the particulate pollution in Denmark and Denmark's possibilities to be active in the international co-operation.
Continuous measurements of ultrafine particles will be established at an urban background station (H.C. Ørsteds Institutet), and the data will be related to acute health effects, e.g. hospital admissions and cases of asthma and allergy. The Danish Ministry of the Interior and
Health, Research Centre for Environmental Health (ISMF) has funded the study.
What can be done in Copenhagen?
It is uncertain which type of particles that are the most hazardous, and it is difficult to quantify the damages. However, many investigations show that the road traffic is the most important Danish source to the particulate pollution in Copenhagen. The particle emissions from the traffic should therefore be reduced by different measures, e.g.
- particle filters on heavy duty vehicles,
- requirements of filters in tenders for operation of public bus lines,
It is recommended to prepare scenario calculations on the different realistic measures. In addition, it is necessary monitor the trends in order to document the effects of the measures taken.
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