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No. 141: Health effects of transboundary air pollution to and from Denmark

Brandt, J., Christensen, J. H. & Jensen, S.S. 2015. Helbredseffekter af grænseoverskridende luftforurening til og fra Danmark. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 46 s. - Videnskabelig rapport fra DCE - Nationalt Center for Miljø og Energi nr. 141. http://dce2.au.dk/pub/SR141.pdf

Summary

Background and objectives

The purpose of this report is to describe the contribution to health effects and related social costs of transboundary air pollution to Denmark from abroad, and from Denmark to foreign countries. Social costs are in this context also termed external costs.

The background is that the countries within the European Union regulate national emissions of member states through national emission ceilings (NEC Directive).

The study

Estimates of health effects and associated external costs of air pollution have been calculated with the EVA system (Economic Valuation of Air pollution) developed by Aarhus University. The EVA system estimates 17 different health effects incl. mortality and morbidity, hospitalization, restricted activity days, etc. In addition to the health effects the external costs are also calculated. The results are given for Denmark and abroad to calculate the contribution of transboundary air pollution.

Calculations are performed for the base emission year 2008/2010 and for 2020. The year 2008/2010 is based on calculations from the particle research project (Nøjgaard et al. 2014). This project used a base year of 2008 for emissions for Europe and 2010 for Denmark, hence termed 2008/2010. This is the most recent available emission data. Emissions for year 2020 are based on the emission reductions in the revised Gothenburg Protocol from 2012.

Also based on the air pollution model results from the particle research project, the contribution of emissions in Europe and Denmark to health effects and external costs in Denmark is presented as well as Denmark’s contribution to health effects and external costs abroad.

How much each country contributes to air pollution in Denmark and how much Denmark contributes to other countries is based on calculations performed by EMEP (European Monitoring and Evaluation Program). EMEP is a scientific and policy-oriented program under the international convention on transboundary air pollution under the UN (Convention on Long-range Transboundary Air Pollution (CLRTAP)).

Main conclusions

Number of premature deaths

In the following the number of premature deaths is used as a health indicator although the EVA system includes 17 health effects on mortality and morbidity.

Anthropogenic emissions in Denmark contribute with about 2,500 premature deaths in Europe (including Denmark) in 2008/2010. This represents about 0.5% of all premature deaths in Europe (including Denmark). The contribution will decrease to about 1,420 premature deaths by year 2020 due to a reduction in emissions in Denmark.

The contribution from Denmark to health effects in Europe outside Denmark is around 2,030 premature deaths in 2008/2010. Denmark's contribution will decrease to about 1,090 premature deaths by year 2020 due to a reduction in emissions in Denmark.

Calculations show about 2,750 premature deaths from air pollution in Denmark in 2008/2010 due to emissions in Denmark and abroad. This is somewhat lower than previous assessments that have estimated about 3,400 premature deaths (Ellermann et al. 2014). The difference is due to the fact that the new calculations are based on emissions from 2008/2010 which are lower than previous emission assumptions for year 2006. Furthermore, the impacts on human health from secondary organic aerosols are not included.  Number of premature deaths will decrease towards year 2020 to about 2,200 premature deaths.

Foreign countries contribute to about 2,270 premature deaths in Denmark in 2008/2010. The foreign contribution to Denmark will decrease towards year 2020 to 1,870 premature deaths due to a reduction in emissions.

Denmark thus contributes to about 480 premature deaths in Denmark in 2008/2010. The contribution of Denmark will decrease forwards year 2020 to about 330 premature deaths because of decreasing emissions in Denmark.

Anthropogenic emissions in Denmark contribute about 15-17% of the total number of premature deaths in Denmark as a result of total regional air pollution over the three years studied, and thus foreign countries (including natural sources)  contributes 83-85% of the total number of premature deaths in Denmark due to air pollution.

External costs of health effects from air pollution

Total external costs related to the health effects of air pollution in Europe in 2008/2010 are about DKK 4,200 billion decreasing to about DKK 3,500 billion in 2020. One DDK is about 0.13 Euro. Emissions of nitrogen oxide compounds constitute the largest contributor to external costs, followed by emissions of sulphur compounds and primary particles. Emissions of carbon monoxide contribute insignificantly compared to the other substances. Overall, it is the primary and secondary particles that contribute most to the external costs while the gases as gasses contribute less (ozone, sulphur dioxide and carbon monoxide).

The contribution from Denmark to external costs related to health effects of air pollution in Europe (including Denmark) in 2008/2010 is about DKK 20 billion declining to about DKK 10 billion in year 2020. Denmark's contribution to the total external costs in Europe is around 0.5%. Emissions of nitrogen compounds constitute the largest contributor to external costs, and nitrogen compounds play an even larger role than was seen for Europe as a whole. The second largest contributor to external costs is the primary particles. The reason that the Danish contribution is large for nitrogen compounds that lead to nitrate particles is due to the relatively high emissions of nitrogen oxides from combustion processes. Furthermore, there are relatively high ammonia emissions from agriculture which form ammonium nitrate and ammonium sulphate in the atmosphere (both secondary particles). In contrast, sulphur dioxide emissions are relatively low, and sulphur contributes relatively little to the external costs.

Denmark's contribution to external costs related to the health effects of air pollution in Europe (excluding Denmark) in 2008/2010 is about DKK 16 billion decreasing to about DKK 8 billion in year 2020.

The external costs in Denmark of the total air pollution in 2008/2010 is about DKK 23 billion declining to about DKK 18 billion in year 2020.

The foreign contribution to external costs in Denmark in 2008/2010 is about DKK 19 billion declining to about DKK 16 billion in year 2020 due to lower emissions.

Denmark's contribution to health-related external costs within Denmark in 2008/2010 is around DKK 3.6 billion declining to DKK 2.5 billion in 2020.

The contribution of foreign emission sources to the total health-related external costs in Denmark is approx. 84-86% depending on the year (2008/2010, 2020). The Danish contribution is 14-16%.

European and Danish emission sources contribution to the external costs in Denmark

The contribution of European emission sources to the external costs related to air pollution in Denmark is based on previous calculations carried out for year 2000 (Ellermann et al., 2014). International shipping contributes about 24%, road traffic about 17%, electricity and heat production about 14%, agriculture about 20% and non-industrial combustion incl. domestic heating about 7%.

The contribution of Danish emission sources to the external costs related to air pollution in Denmark is also based on previous calculations, however, for year 2008 (Ellermann et al., 2014). The contribution of the Danish emission sources is distributed in the following way: 33% from the agricultural sector, 16% from road traffic, and about 30% from non-industrial combustion incl. domestic heating, which in Denmark is almost exclusively related to wood stoves and boilers. Danish sources have a high percentage of agricultural and domestic heating compared to European sources. For the agricultural sector it is particularly ammonia which contributes to the external costs due to the contribution to the formation of secondary particles containing ammonium. For domestic heating it is primarily directly emitted particles from wood stoves.

Contribution of foreign countries to air pollution in Denmark and Denmark's contribution to foreign countries

The contribution of foreign countries to air pollution in Denmark and Denmark's contribution to them is examined for health-related indicators PM2.5 and SOMO35 based on calculations performed by EMEP for the year 2011. PM2.5 is particles less than 2.5 micro meters in diameter, and SOMO35 is an indicator of the sum of the highest ozone concentrations. The ozone contribution is subdivided into the contribution from emissions of volatile organic hydrocarbons (VOCs) and nitrogen oxides (NOx) as these groups of substances contribute to the formation of ozone in the atmosphere. Ozone chemistry is non-linear and the contribution of NOx emissions can be both positive and negative depending on the chemical regime. For example, NOx emission in Denmark contributes to reduction of ozone concentrations in Denmark, while it contributes to an increase in ozone farther from Denmark.

Germany contributes the most to the total PM2.5 concentrations in Denmark with 22%, followed by Denmark itself by 20%. Other countries / regions contributing are United Kingdom with 9%, ships in the North Sea with 9% and 4% from ships in the Baltic Sea, and Poland with 8%. The reason why these countries contributes the most is partly because they are close to Denmark and have relatively high emission density covering large areas, but also the dominant wind direction from southwest, bringing pollution to Denmark.

Germany and the United Kingdom contribute the most to the sum of the highest ozone concentrations in Denmark for VOC emissions. For NOx emissions the picture is more complex. Countries and regions (ships) which are close to Denmark and Denmark by itself contribute to a reduction in the sum of the highest concentrations in Denmark (contribution has negative sign). This is because NO (part of NOx) reacts with ozone to form NO2 and thereby reduces ozone. Countries and regions (ships) which are further away contribute to the sum of the highest ozone concentrations in Denmark (contribution has positive sign) as ozone formation is a large-scale phenomenon, which is formed from VOC and NOx emissions under the influence of sunlight and temperatures.

Denmark's contribution to foreign countries

Denmark is the biggest contributor to PM2.5 concentrations in Denmark, which accounts for 20%. Denmark's largest contribution to PM2.5 concentrations in other countries is to Sweden with about 6% of PM2.5 concentrations in Sweden, reflecting the dominant southwest wind direction blowing part of Danish particle pollution to Sweden.

Denmark contributes the most to the sum of the highest ozone concentrations in Denmark for VOC emissions, and then to Sweden and Norway.

For NOx emissions, the picture is more complex. Denmark contributes to a reduction in the sum of the highest ozone concentrations in Denmark by about 11% (contribution has a negative sign). This is because NO reacts with ozone to form NO2 and thereby reduces ozone. Denmark's contribution to other countries is very small and there is not a clear picture of how NOx emissions from Denmark affect the other countries, as we are close to zero.

Project results

Summary of premature deaths

As an overview, the number of premature deaths (total) is summarized for different assumptions and years.

Number of premature deaths in Europe will fall from year 2008/2010 to year 2020 due to a general reduction in emissions. Foreign contributions to premature deaths in Denmark will also decrease until year 2020 according to the emission scenarios.

Denmark's contribution to the number of premature deaths in Europe will be reduced in year 2020 due to lower emissions in Denmark. Denmark's contribution to the number of premature deaths in Denmark will follow the same pattern.

Summary of total external costs

The total external costs related to the health effects of air pollution are summarized in Table 2.2.

The external costs in Europe will fall from year 2008/2010 to year 2020 due to a reduction in emissions. Foreign contributions to external costs in Denmark will also decrease until year 2020.

Denmark's contribution to external costs in Europe will be reduced until year 2020 due to lower emissions in Denmark. Denmark's contribution to external costs in Denmark follows the same pattern.

The contribution of foreign emission sources to the total health-related external costs in Denmark is approx. 85%. The Danish contribution is 15%.

Uncertainties

There is uncertainty in the modelling of health effects and external costs, as there is uncertainty related to all parts from emissions, concentration, population exposure, exposure-response relationship for estimation of health effects, and the economic valuation of health effects. The uncertainty of the calculated concentration can be determined by comparison with air quality measurements, while it is difficult to quantify the uncertainty of the other part.

In the calculations it is assumed that all types of particles are equally harmful. These calculations include both primary emitted particles and secondary inorganic particles formed from gases emitted into the atmosphere. The impacts from secondary organic aerosols are not included in the present study. However, there is still uncertainty as to which particles and which chemical composition gives rise to the health effects observed in health studies. In a recent health effect review study for Danish conditions (Ellermann et al. 2014), it is concluded based on state-of-the-art knowledge that it is not possible at the moment to separate the different health effects of different types of particles and chemical composition, and therefore, all particles are assumed to be equally harmful in these calculations.