7. Nitrous Oxide N2O

7. NITROUS OXIDE - N₂O

7.1 N₂O-emissions by countries

The 1990 annual total N₂O-emissions for EUROPE were estimated to be 1.9 million tonnes. These emissions broken down by EU-12, EFTA-5 and PHARE-10 countries are shown in figure 7.1. The largest contributor were the EU-12 countries with 69%, second largest the PHARE-10 countries with 24%; the EFTA-5 countries contributed 5% and Germany (former East) and Malta 2%.

Figure 7.1: Contribution in % to the EUROPEAN total N₂O-emissions

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Figure 7.2 shows the relative contribution of individual countries to the total of 1.9 million tonnes. In 1990 the largest contributing countries were France (12%), Spain and Greece (each 11%); the smallest contributing countries were Malta (0.004%), Luxembourg (0.04%), Estonia (0.2%) and Austria (0.4%).These differences are due to different size of population, different per capita emissions (see also paragraph 7.3) and differences in emissions from natural sources.

Figure 7.2: Contribution in % of each country to the EUROPEAN total N₂O-emissions

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7.2 N₂O-emissions per group

More than two thirds of the N₂O-emissions for EUROPE resulted together from agriculture (group 10, 39%) and nature (group 11, 29%) in 1990. Group 4 (production processes) contributed with 19% and group 1 (public power, cogeneration and district heating) with 5% to the N₂O-emissions. Group 2 (commercial, institutional and residential combustion), group 3 (industrial combustion), group 7 (road transport) and group 9 (waste treatment and disposal) produced the remaining 8% of the N₂O-emissions in EUROPE. Other groups were not relevant for N₂O-emissions.

The split of the N₂O-emissions into groups for EU-12 countries, PHARE-10 countries and EFTA-5 countries is quite similar compared to the split for EUROPE with the exception of the larger contribution of group 1 (public power, cogeneration and district heating; 9%) and group 10 (agriculture; 53%) in the PHARE-10 countries as well as of group 4 (production processes; 24%) in the EU-12 countries and the smaller contribution of group 4 (7%) in the PHARE-10 countries.

The differences of contributions especially of the main source groups 11, 10, 4 and 1 to the total emissions are larger between countries than these groups (see also table 7.1). The relative contribution of the N₂O-emissions of group 11 (nature) ranges from 88% (Greece) to 0% (Norway, Hungary, Malta and United Kingdom), of group 10 (agriculture) from 88% (Ireland and Lithuania) to 6% (Greece), of group 4 (production processes) from 53% (Germany former West) to 0% (Denmark and others) and of group 1 (public power, cogeneration and district heating) from 16% (Belgium, Flemish region) to 0% (the Netherlands, Norway and Switzerland).

However it is evident from these differences in the relative contribution of sourcegroups to a countries total emissions that strategies for reduction of N₂O-emissions need individual solutions as well as common elements.

Figure 7.3: Contribution in % of source groups to the EUROPEAN N₂O-emissions

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7.3 N₂O-emissions per capita

Only anthropogenic emissions are expected to be related to population for these calculations. Therefore group 11 (nature) has been excluded.

For EUROPE the average N₂O-emissions per capita were 3 kg/capita. Compared to this number the per capita N₂O-emissions were equal for the EU-12 countries with 3 kg/capita, 33% smaller for the EFTA-5 countries with 2 kg/capita and equal for the PHARE-10. This comparison is also shown in figure 7.4 and table 9.

Significant different to the average of EUROPE are the per capita N₂O-emissions in Ireland with 12 kg/capita. The smallest per capita N₂O-emissions were in Malta with 0 kg/capita, Austria and the Netherlands with 1 kg/capita (see figure 7.5). In most of the countries the per capita N₂O-emissions are between 2 kg/capita and 4 kg/capita. The smallest per capita emissions is a factor of larger than 12 smaller compared to the largest number.

Figure 7.4: N₂O-emissions per capita for EUROPE

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Figure 7.5: N₂O-emissions per capita for individual countries

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7.4 N₂O-emissions per km²

The emissions per km² have been calculated from the total emissions, the emissions of group 11 (nature) having been included in this case.

For EUROPE the average N₂O-emissions per km² were estimated as 397 kg/km². Compared to this number the per km² N₂O-emissions were 44% larger for the EU-12 countries with 570 kg/km², 7% larger for the PHARE-10 countries with 426 kg/km² and 80% smaller for the EFTA-5 countries with 81 kg/km². This comparison is also shown in figure 7.6 and table 10.

Figure 7.6: N₂O-emissions per km² for EUROPE

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Again the differences are much larger if individual countries are compared: the largest N₂O-emissions per km² were for Greece (1 555 kg/km²) and the next largest ones for Belgium, Flemish region (926 kg/km²), Belgium, Wallonie region (810 kg/km²) and Czech Republic (789 kg/km²). The smallest emissions per km² for N₂O were for Norway (48 kg/km²), Sweden (73 kg/km²) and Finland (94 kg/km²). Figure 7.7 shows the countries ranked according their N₂O-emission per km². The differences in the emissions per km² between countries are much larger compared to the per capita emissions. The smallest number being 32 times smaller than the largest number.

Figure 7.7: N₂O-emissions per km² for individual countries

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Table 7.1: Nitrous oxide emissions per country and group