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7. Emission sector contributions to air quality in 2030

In the following sections we will provide information for the Nordic capital cities København, Helsinki, Stockholm and Reykjavík on the contribution to air quality in the city from different emission sectors. The results are divided into the contribution from the city, the contribution from the country of the city (disregarding emissions from the city) and the contribution from sources abroad. Abroad includes both anthropogenic emissions at land and sea as well as natural sources e.g. sea salt, and the concentration contribution to the city is not broken down by emission sectors but given as a total concentration contribution. The reason why the contribution from abroad has not been broken down on emission sectors is that as it is computationally expensive and it would also be too time consuming to analyse and report on results.
The results for each city are presented as the average concentration contribution to the urban background concentration over the city defined as the area given by the administrative boundaries, see Appendix 1. Estimates are based on calculations with DEHM and UBM. The analysis focuses on 2030 to illustrate the potential benefits of regulation of the different emission sectors in the future. Furthermore, the focus is on PM2.5 and NO2 as they are the largest contributors to health effects.
A former modelling study based on DEHM has also looked into the sectoral contributions of anthropogenic emissions in the four Nordic countries (Denmark, Finland, Norway and Sweden) on air pollution levels and the associated health impacts and costs over the Nordic and the Arctic regions for the year 2015 (Im et al., 2019).

7.1 København

The contributions to urban background concentrations in København from different emission sectors in København, from emission sectors in the rest of Denmark and from emission sources abroad are shown in Table 7.1 for PM2.5 and for NO2 in Table 7.2.
The contribution of PM2.5 to the urban background concentration in København from the city is approx. 8% (0.6 µg/m3), from the rest of Denmark approx. 16% (5.1 µg/m3), and from abroad approx. 76% (6.8 µg/m3). The contribution from emissions abroad is very high due to the location of København, which is affected by a large contribution from both primary but especially secondary particles formed in the atmosphere due to emissions in Central Europe and atmospheric transport (Jensen et al., 2021).
Table 7.1. Emission sector contributions to the urban background PM2.5 concentrations in København in 2030.
København
Contribution to the urban background concentration in 2030
From city
From DK
Abroad
Total
From city
From DK
Abroad
Total
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
0.1
0.1
1%
1%
2 (Residential comb.)
0.2
0.4
3%
6%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
0.03
0.1
0%
1%
7 (Road transport)
0.2
0.2
3%
3%
8 (Off-road, without shipping)
0.01
0.1
0%
1%
10 (Agriculture)
<0.01
0.2
0%
3%
Total
0.6
1.1
5.1
6.8
8%
16%
76%
100%
For NO2 the picture is somewhat different as local sources play a larger role where local combustion sources are important contributors compared with PM2.5. The NO2 contribution to the urban background concentration in København from the city is approx. 18% (3.0 µg/m3), from the rest of Denmark approx. 28% (4.8 µg/m3), and from abroad approx. 54% (9.3 µg/m3).
Table 7.2. Emission sector contributions to the urban background NO2 concentrations in København in 2030.
København
Contribution to the urban background concentration in 2030
From city
From DK
Abroad
Total
From city
From DK
Abroad
Total
NO2
NO2
NO2
NO2
NO2
NO2
NO2
NO2
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
0.8
1.0
5%
6%
2 (Residential comb.)
0.2
0.5
1%
3%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
0.01
0.1
1%
1%
7 (Road transport)
1.0
1.0
6%
6%
8 (Off-road, without shipping)
0.9
2.0
5%
12%
10 (Agriculture)
<0.01
0.2
0%
1%
Total
3.0
4.8
9.3
17.81
18%
28%
54%
100%
The two single largest contributions to the urban background concentrations in 2030 from city emissions of PM2.5, are from the sectors road transport (SNAP7) and residential wood combustion (SNAP2). For NO2 the single largest contribution is from road transport (SNAP7), but all other emission sectors including combustion sources also contribute.
The single largest contribution to the urban background concentrations in 2030 from country emissions of PM2.5 is from the sector residential wood combustion (SNAP2), but all other sectors also contribute. For NO2 the three largest contributions are from the sectors off-road (SNAP8), road transport (SNAP7) and the combined sector of energy, industrial combustion and industrial processes (SNAP134).

7.2 Stockholm

The contributions to the urban background concentrations in Stockholm from different emission sectors in Stockholm, emission sectors in the rest of Sweden and emission sources abroad are shown in Table 7.3 for PM2.5 and for NO2 in Table 7.4.
The contribution of PM2.5 to the urban background concentration in Stockholm from the city is approx. 26% (1.5 µg/m3), from the rest of Sweden approx. 23% (1.3 µg/m3), and from abroad approx. 51% (2.9 µg/m3). The contribution from abroad is largely due to a large contribution from secondary long-range transported particles.
Table 7.3. Emission sector contributions to the urban background PM2.5 concentrations in Stockholm in 2030. 
Stockholm
Contribution to the urban background concentration in 2030
From city
From SE
Abroad
Total
From city
From SE
Abroad
Total
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
0.5
0.2
9%
4%
2 (Residential comb.)
0.2
0.3
4%
5%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
0.1
0.1
2%
2%
7 (Road transport)
0.6
0.5
11%
9%
8 (Off-road, without shipping)
0.1
0.1
2%
2%
10 (Agriculture)
<0.01
0.1
0%
2%
Total
1.5
1.3
2.9
5.7
26%
23%
51%
100%
For NO2 there is only a slightly larger contribution from the city and country compared with PM2.5. However, the difference is much less profound compared with København. The contribution of NO2 to the urban background concentration in Stockholm from the city is approx. 27% (3.7 µg/m3), from rest of Sweden approx. 18% (2.5 µg/m3), and from abroad approx. 55% (7.7 µg/m3).
Table 7.4. Emission sector contributions to the urban background NO2 concentrations in Stockholm in 2030. 
Stockholm
Contribution to the urban background concentration in 2030
From city
From SE
Abroad
Total
From city
From SE
Abroad
Total
 
NO2
NO2
NO2
NO2
NO2
NO2
NO2
NO2
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
2.0
0.6
14%
4%
2 (Residential comb.)
0.2
0.4
1%
3%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
<0.01
0.01
0%
0%
7 (Road transport)
1.0
0.9
7%
6%
8 (Off-road, without shipping)
0.5
0.5
4%
4%
10 (Agriculture)
<0.01
0.1
0%
1%
Total
3.7
2.5
7.7
13.9
27%
18%
55%
100%
The two largest contributions to the urban background concentrations in 2030 from city emissions of PM2.5 are from the sectors road transport (SNAP7) and the combined sector of energy, industrial combustion and industrial processes (SNAP134). The contribution from residential wood combustion (SNAP2) is the third largest with the same contribution as in København (0.2 µg/m3). For NO2 the two sectors with the largest contributions are the combined sector of energy, industrial combustion and industrial processes (SNAP134) and transport (SNAP7).
For country emissions of PM2.5, the single largest contribution to urban background concentrations in 2030 is from the sector road transport (SNAP7), followed by residential wood combustion (SNAP2) and the combined sector of energy, industrial combustion and industrial processes (SNAP134). For NO2 the three largest contributions are from the same sectors but in slightly different order: road transport (SNAP7), the combined sector of energy, industrial combustion and industrial processes (SNAP134) and residential wood combustion (SNAP2).

7.3 Helsinki

The contribution to the urban background concentrations in Helsinki from different emission sectors in Helsinki, emission sectors in the rest of Finland and emission sources abroad are shown in Table 7.7 for PM2.5 and for NO2 in Table 7.8.
The contribution of PM2.5 to the urban background concentration in Helsinki from the city is approx. 15% (0.7 µg/m3), from the rest of Finland approx. 22% (1.0 µg/m3), and from abroad approx. 62% (2.9 µg/m3). The contribution from abroad is largely due to a large contribution from secondary long-range transported particles.
Table 7.5. Emission sector contributions to the urban background PM2.5 concentrations in Helsinki in 2030. 
Helsinki
Contribution to the urban background concentration in 2030
From city
From FI
Abroad
Total
From city
From FI
Abroad
Total
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
0.1
0.2
2%
4%
2 (Residential comb.)
0.1
0.3
2%
6%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
0.1
0.0
2%
1%
7 (Road transport)
0.3
0.3
6%
6%
8 (Off-road, without shipping)
0.1
0.1
2%
2%
10 (Agriculture)
<0.01
0.1
0%
2%
Total
0.7
1.0
2.9
4.7
15%
22%
62%
100%
For NO2 there is a larger contribution from the city compared with PM2.5 as local sources play a larger role where combustion sources are important contributors. The NO2 contribution to the urban background concentration in Helsinki from the city is approx. 25% (4.7 µg/m3), from the rest of Finland approx. 22% (4.1 µg/m3), and from abroad approx. 54% (10.3 µg/m3).
Table 7.6. Emission sector contributions to the urban background NO2 concentrations in Helsinki in 2030. 
Helsinki
Contribution to the urban background concentration in 2030
From city
From FI
Abroad
Total
From city
From FI
Abroad
Total
 
NO2
NO2
NO2
NO2
NO2
NO2
NO2
NO2
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
3.0
2.0
16%
10%
2 (Residential comb.)
0.1
0.4
1%
2%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
<0.01
<0.01
0%
0%
7 (Road transport)
0.9
1.0
5%
5%
8 (Off-road, without shipping)
0.7
0.6
4%
3%
10 (Agriculture)
0.01
0.1
0%
1%
Total
4.7
4.1
10.3
19.1
25%
22%
54%
100%
The emission sector contributing the most to the urban background concentrations of PM2.5 in 2030 from city emissions is road transport (SNAP7), but all other sectors also contribute, except agriculture (SNAP10).
The three largest contributions to urban background concentrations of PM2.5 in 2030 from country emissions are from the sectors residential wood combustion (SNAP2), road transport (SNAP7) and the combined sector of energy, industrial combustion and industrial processes (SNAP134). For NO2 the three largest contributions are from the combined sector of energy, industrial combustion and industrial processes (SNAP134), road transport (SNAP7) and off-road (SNAP8).

7.4 Reykjavík

The contribution to the urban background concentrations in Reykjavík from different emission sectors in Reykjavík, emission sectors in the rest of Iceland and emission sources abroad are shown in Table 7.9 for PM2.5 and for NO2 in Table 7.10.
The contribution of PM2.5 to the urban background concentration in Reykjavík from the city is approx. 10% (0.2 µg/m3), from rest of Iceland approx. 23% (0.5 µg/m3), and from abroad approx. 67% (1.5 µg/m3). Due to the remote location, the concentration levels of PM2.5 are low compared with other capital cities, however, the contribution from abroad is relatively large although the absolute levels are low. The contribution from abroad are from ship emissions, long-range transport and sea salt.
Table 7.9. Emission sector contributions to the urban background PM2.5 concentrations in Reykjavík in 2030. 
Reykjavík
Contribution to the urban background concentration in 2030
From city
From IS
Abroad
Total
From city
From IS
Abroad
Total
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
PM2.5
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
0.05
0.2
2%
10%
2 (Residential comb.)
<0.01
<0.01
0%
0%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
0.03
<0.01
1%
0%
7 (Road transport)
0.1
0.0
3%
2%
8 (Off-road, without shipping)
0.1
0.2
3%
7%
10 (Agriculture)
0.01
0.1
0%
4%
Total
0.2
0.5
1.5
2.3
10%
23%
67%
100%
For NO2 there is a larger contribution from the city compared with PM2.5 as local sources play a larger role where combustion sources are important contributors. The NO2 contribution to the urban background concentration in Reykjavík from the city is approx. 35% (3.6 µg/m3), from the rest of Iceland approx. 42% (4.3 µg/m3), and from abroad approx. 23% (2.4 µg/m3).
Table 7.10. Emission sector contributions to the urban background NO2 concentrations in Reykjavik in 2030.
Reykjavik
Contribution to the urban background concentration in 2030
From city
From IS
Abroad
Total
From city
From IS
Abroad
Total
NO2
NO2
NO2
NO2
NO2
NO2
NO2
NO2
SNAP emission sectors
(µg/m3)
(µg/m3)
(µg/m3)
(µg/m3)
(%)
(%)
(%)
(%)
1 (Energy)
3 (Industrial comb.)
4 (Industrial proc.)
0.1
0.6
1%
6%
2 (Residential comb.)
0.01
<0.01
0%
0%
5 (Extraction etc.)
6 (Solvents)
9 (Waste)
<0.01
<0.01
0%
0%
7 (Road transport)
0.1
0.01
1%
0%
8 (Off-road, without shipping)
2.9
3.5
28%
34%
10 (Agriculture)
0.4
0.2
4%
1%
Total
3.6
4.3
2.4
10.3
35%
42%
23%
100%
The two largest contributions to the urban background concentrations of PM2.5 in 2030 from city emissions are from the sectors road transport (SNAP7) and off-road (SNAP8). The latter includes emissions from the fishing fleet where there is uncertainty of the geographic distribution of emissions that leads to overestimation of the contribution to concentrations in Greater Reykjavík. As the only Nordic capital city, the contribution from residential wood combustion (SNAP2) is insignificant. For NO2 the largest contribution is from off-road (SNAP8) but this is also overestimated due to the incorrect geographic distribution of emissions from fisheries.
The three largest contributions to the urban background concentrations of PM2.5 in 2030 from country emissions are from the combined sector of 5 (Extraction etc.) 6 (Solvents) and 9 (Waste) (SNAP569), the combined sector of energy, industrial combustion and industrial processes (SNAP134) where an important source is ferroalloys production, and off-road (SNAP8) related to the fishing fleet. For NO2 the three largest contributions are from the sectors off-road (SNAP8), the combined sector of energy, industrial combustion and industrial processes (SNAP134) and agriculture (SNAP10).

7.5 Summary of contributions to air quality in 2030

Table 7.11 summarises the contributions to air quality in 2030 for the Nordic capital cities.
 
From city
From country
From abroad
Total
 
PM2.5
PM2.5
PM2.5
PM2.5
København
8%
16%
76%
100%
Stockholm
26%
23%
51%
100%
Oslo
n.a.
n.a.
n.a.
n.a.
Helsinki
15%
22%
62%
100%
Reykavík
10%
23%
67%
100%
 
NO2
NO2
NO2
NO2
København
18%
28%
54%
100%
Stockholm
27%
18%
55%
100%
Oslo
n.a.
n.a.
n.a.
n.a.
Helsinki
25%
22%
54%
100%
Reykavík
35%
42%
23%
100%
Table 7.11. The contribution to the urban background concentrations of PM2.5 (top rows) and NO2 (bottom rows) from city emissions, from country emissions and from emissions abroad in 2030 for the Nordic capital cities.
The contribution to urban background concentrations of PM2.5 in 2030 for the Nordic capital cities ranges from 8% to 26% from city emissions, 16% to 23% for country emissions and 51% to 76% from abroad emissions. The corresponding numbers for NO2 are 18% to 35%, 18% to 42% and 23% to 55%, respectively.
København stands out with the highest contribution from emissions abroad and low contributions from city and country emissions to urban background concentrations of PM2.5 also due to its location close to Central Europe.
Reykjavík has a relatively large contribution from abroad despite its location in the North Atlantic Ocean. However, the absolute levels are the lowest among the capital cities. Possible explanations could be the influence of ship emissions, long-range transport and sea salt. Moreover, Reykjavík and Iceland have a relatively small population further adding to the relative importance of emissions from abroad.
The results for Stockholm and Helsinki are more similar to each other and the contributions from emissions from city, country and abroad differ from that found for Reykjavík and København.
The three largest contributions to the urban background concentrations of PM2.5 in 2030 from city emissions are from road transport (SNAP7), residential wood combustion (SNAP2) and the combined sector of energy, industrial combustion and industrial processes (SNAP134), except for Reykjavík where the contribution from residential wood combustion is insignificant and off-road (SNAP8) plays a larger role due to the fishing fleet although overestimated. For NO2 the largest contribution is from the sector road transport (SNAP8), but all other sectors with emissions from combustion sources also contribute.
For country emissions, the largest contributions to the urban background concentrations of PM2.5 in 2030 are from residential wood combustion (SNAP2) (except for Iceland), road transport (SNAP7), the combined sector of energy, industrial combustion and industrial processes (SNAP134) and off-road (SNAP8), but also agriculture (SNAP10) contributes. For NO2 the largest contributions are from the sectors off-road (SNAP8), road transport (SNAP7), and the combined sector of energy, industrial combustion and industrial processes (SNAP134).
The contribution from abroad has not been broken down in emission sectors.
Nordic Council of Ministers I www.norden.org/publications I pub@norden.org