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Reduction Success Local Emissions

Effective reductions of PM10 and soot concentrations

Background emissions of air pollutants always play a role in the overall composition of cities’ air pollution. But in most cases, local traffic is the biggest contributor to high concentrations. By reducing its emissions, a lot can be done to improve air quality and comply with EU wide limit values for PM10 set for the protection of public health. The PM10 daily limit values is set at 50 µg/m3 24-hour mean with a maximum of 35 permitted exceedances per year and entered into force on the 1st of January 2005. We compared the number of days exceeding the PM10 limit in 2005 with the latest reported data for 2009. We compared the measurements at traffic stations and background stations in order to better understand the role played by local traffic for both years. The data was collected from AirBase, the public air quality database system of the European Environmental Agency (EEA). In some cases, the data appeared inconsistent or incomplete, which resulted in a lower grading.



After a decrease in the number of days exceeding the limit value for PM10 between 2005 and 2009, a further reduction could be recorded until 2012. At the traffic station Stampfenbachstrasse, emissions decreased from 12 exceedance days in 2009 to 9 exceedance days in 2012. At the same time, the Kaserne background station reported 11 exceedance days in 2009 and 7 in 2012. Annual mean values for PM10 decreased from 22.6 µg/m³ to 19.8 µg/m³ between 2009 and 2012 at the traffic station, and from 19.6 µg/m³ to 17.4 µg/m³ at the background station.

The national limit value for PM10 annual mean values is 20 µg/m³ and one exceedance day per year (instead of the 40 µg/m³ mandated by EU regulations). NO2 annual mean values decreased and, at 34.0 µg/m³, were below the EU limit value of 40 µg/m³ for Stampfenbachstrasse in 2012, just missing the national limit values of 30 µg/m³.

Department of Health and Environment Zurich (Ger.):

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Capital of Austria

In 2012 and 2013, Vienna achieved a reduction of urban concentrations below the limit values for PM10 (30 µg/m³ and 30 µg/m³) and missed compliance with NO2 annual limits by a very small fraction in both years (40,5 µg/m³ and 40 µg/m³).

In Vienna’s case, the share of local emissions in overall PM10 emissions is low with only 25%, compared to 75% background emissions that mostly come from outside Austria, with similar background shares also for NO2. Within the local emissions, the share of traffic is very high with 81% for PM10 and 82% for NO2.

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Capital of Finland

Between 2006 and 2012, PM10 exceedance days dropped from 37 to only 6 at the traffic station Mannerheimintie. Accordingly, the PM10 annual mean values decreased from 30.0 µg/m³ in 2006 to 21.3 µg/m³ in 2012. At the same time, the number of exceedance days at the background station Kallio 2 declined from 10 to zero. Also the annual mean values are on a very low level and decreased from 16.6 µg/m³ to 12.7 µg/m³.

Until 2010, Helsinki had problems sticking to the annual EU NO2 limit of 40 µg/m³. While in 2006 N02 values at the traffic station were 42.2 µg/m³, they decreased from 2011 to a level of 36.5 µg/m³ in 2012. The background station could be lowered by nearly 20% from 23.9 µg/m³ to 19.8 µg/m³.

In Helsinki and Finland in general, air pollution problems are especially severe during spring because of usage of studded tires and loose chippings on streets in winter.

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Capital of Ireland

Between 2008 and 2012 the City of Dublin was able to decrease its already low PM10 levels. The traffic station Winetavern Street recorded 7 exceedance days in 2008 and 0 in 2012. The annual mean decreased from 17.5 to 12.6 μg/m3. Interestingly, the background station Rathmines has generally higher numbers of exceedance days than the traffic station. From 2008 to 2012, PM10 exceedance days decreased from 11 to 8, and PM10 annual mean values had only marginal fluctuations around 17 μg/m3.

NO2 concentrations in Dublin are around EU limitations and decreased at the traffic station from 34 in 2008 to 31 in 2012. In the same time period, values at the background station decreased from 23.0 to 21.2 μg/m3.

There are reasonable doubts that the location of monitoring stations does not entirely and accurately reflect air pollution in Dublin. Requests by NGOs to install air quality monitoring at locations where high concentrations have been identified (city centre and inner suburbs) have not been successful.

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Capital of the Netherlands

Amsterdam has an air pollution problem and the progress in reduction needs to continue. However, EU limit values have almost been reached. Especially for PM10, Amsterdam has consistently remained below the limit values in recent years. Interestingly, at the measurement station Prins Bernhardplein the annual PM10 increased between 2008 and 2011, as did the number of exceedance days. For NO2, compliance is almost complete. There was a minor reduction trend in Prins Berhardplein (NO2 annual mean) to 40.3µg/m³ in 2011.

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Capital of Denmark

Copenhagen has relatively low air pollution levels, both for PM10 and for NO2. Some traffic measurement stations even comply with NO2 limits, however the station H.C. Andersens Boulevard still reports NO2 levels above EU limit values: in comparison with 2008 levels of 54.9 µg/m³, measurements in 2012 showed 55.1 µg/m³. However, the limit values are potentially within reach. For PM10, the city is complying with the limit values with levels of between 33.2 µg/m³ in 2008 and 30.8 µg/m³ in 2012. The city states a large background share for both particles (PM2.5) and NO2, of 89% and 60% respectively.

Clean Air Copenhagen 2014 (Engl.):…

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Capital of Sweden

Since 2008, Stockholm’s air quality stations have registered a continuous reduction trend in both PM10 and NO2, for example at the traffic measurement station Hornsgatan. The annual mean for PM10 decreased from 36.8 µg/m³ in 2008 to 25.7 µg/m³ in 2012. NO2 at the same time decreased from 46.1 µg/m³ to 42.6 µg/m³. However, the recorded levels of both pollutants were still in breach of the EU limit values (exceedance days for PM10 in 2012 were not). The high levels of NO2 and PM10 at the traffic station are almost exclusively from traffic. In comparison, the background station Södermalm recorded very low levels of both PM10 (13.4 µg/m³) and NO2 (11.9 µg/m³)

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Capital of Germany

Berlin shows no clear reduction trend since 2008. Daily exeedances of PM10 have even increased in single years at measuring stations with high traffic volumes. Daily limit values were exceeded at some stations in 2014, but annual mean concentrations could be considerably reduced below the EU limit value of 40 µg/m3 to 32 µg/m3.

Nevertheless, NO2 concentrations (annual means) are still slightly higher than the EU threshold. But if the reduction trend of the last years is going to be continued compliance will be reached during the next two years (2014: 42 µg/m3 NO2 at station Frankfurter Allee). Other measuring stations show higher exceedances of NO2.

More information on air monitoring (Ger.):…

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A significant reduction trend of PM10 concentrations can be seen in all traffic stations leading below the daily and annual EU limit values except for the measuring station Am Neckartor. About 15% reduction could be reached at the traffic station Neckartor so far. The annual threshold is kept, but daily concentrations (63 exceedance days in 2014) are still considerably above EU limit values. Due to the city’s location in a basin, its meteorological situation is characterised by frequent low exchange weather conditions (thermal inversions).

Exceedances of the annual NO2 limit values occur at most traffic stations (Am Neckartor, Hohenheimer Straße, Arnulf-Klett-Platz), but the hourly NO2 limit values are no longer exceeded.

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After a strong reduction in annual PM10 exceedance days from 117 to 54 between 2005 and 2009, the traffic station Graz Don Bosco achieved a further decrease to 50 exceedance days by 2012. An intermediate high of 75 days was recorded in 2011. Accordingly, the annual mean value for PM10 decreased from 34.3 µg/m³ to 33.1 µg/m³, with an intermediate high of 40.3 µg/m³. At the same time, exceedance days at the background station Graz Süd decreased from 45 to 35. Again, an intermediate high of 71 exceedance days was recorded for 2011.

Graz has problems complying with EU limits for the NO2 annual mean value: the traffic station Don Bosco has not shown a reduction trend, but has fluctuated between 51.3 and 47.2 µg/m³ since 2008. Graz also monitors high NO2 annual mean values for the background station of about 33 µg/m³ on average. This is due to the geographical location. Graz generally has a difficult task, as it is hard for air pollution to escape from the basin-shaped valley.

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In Dusseldorf a clear improvement trend is visible, although the levels of pollution are still high. Nevertheless the annual mean concentration in the street with the highest pollution load (Corneliusstr.) could be kept below the EU limit value of 40 µg/m3 since 2005. Daily exceedances could also be reduced from 70 µg/m3 to around 40 µg/m3. The new action plan is conceived to stay constantly below the 35 permitted daily exceedances.

But the reductions of NO2 are insufficient and there is no clear decrease discernible which may lead to compliance in the next years. The hot spot Corneliusstraße still has an annual mean concentration of NO2 of 60 µg/m3).

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Capital of Belgium

Since 2008 the number of days exceeding the PM10 daily limit values at the Molenbeek traffic station decreased significantly from 46 to 29 (2012), the annual mean concentration reduced from 32.2 to 25.3 µg/m3 (2012). The background concentration of PM10 at the Uccle station has remained at a high level for years, at 25.9 µg/m3 in 2012. NO2 annual mean concentrations slightly decreased from 43.8 to about 40.6 µg/m³ between 2008 and 2012, not far above the EU limit value of 40µg/m³. Background concentrations of NO2 are relatively low.

Traffic is one of the most important sources of pollution in the city. Locally, traffic is the highest pollution source, with a 72% share for PM10 and a 61% share for NOx.

Note: Due to a editorial mistake, the website initially claimed that the NO2 levels reached „conformity with the EU limit values.“ With an annual limit of 40µg/m³, Brussel is not far above, however it did not reach compliance so far.

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Barcelona’s PM10 levels seem to be below the EU limit values, even though, for example, the air quality measurement station Barcelona missed data for 2009 and 2010 and has only measured with a validity of above 80% since 2011. Overall, Barcelona measurement data appears rather unreliable. For NO2 there appears to be a slight reduction trend, however caution is advised and levels are still in breach of EU limits, at 60.7 µg/m3 in 2012.

With regard to sources, urban and regional traffic accounts for 48.2% of NOx and 61.6% of PM10 emissions. The second largest contributor is maritime operations with 29.5% of NOx and 18.5% of PM10, including Barcelona’s port. Industry is the third largest contributor with 13.4% and 17.9%. The smallest contributor is the residential sector with 8.9% and 1%, respectively. These figures were calculated in 2008.

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Capital of Czech Republic

During recent years, PM10 exceedance days have fluctuated massively, being consistently far above EU limit values: Between 2008 and 2012, the number of exceedance days of PM10 decreased at the Smíchov traffic station from 72 to 38, with an intermediate high of 77 exceedance days in 2010. Nevertheless, annual mean concentrations of PM10 are below EU limits and decreased from 36.1 µg/m3 to 30.2 µg/m3 between 2008 and 2012.

Prague consistently experienced NO2 concentrations above EU limit values between 2008 and 2012, although a slight reduction trend within this time could be detected: annual mean values decreased from 46.3 to 42.4 µg/m3. Unverified data for 2013 and 2014 show a further decrease in the PM10 and NO2 concentrations, which possibly leads to compliance with EU limits.

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United Kingdom

From 2008 to 2012, PM10 exceedance days at the traffic station Kerbside decreased from 42 to 7. At the same time, the background station Centre reported only 6 exceedance days in 2008 and 2 in 2011. Annual mean values for PM10 declined from 31.5 to 23.9 µg/m³ at Kerbside traffic station between 2008 and 2012*. Glasgow thus managed to stay consistently below EU limit values (35 exceedances and 40 µg/m³ annual mean). A serious problem, however, exists for NO2. Even though annual mean levels decreased from 82.5 to 72.3 µg/m³ in the meantime, Glasgow did not manage to comply with EU NO2 limit values (40 µg/m³).

Road transport is responsible for more than 40% of PM10 and more than 50% of NOx levels.

(*) Values for 2012 have a validity below 80% according to EEA AirBase.

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Capital of Portugal

The city of Lisbon experienced an only slight reduction of pollutants. Between 2008 and 2012, annual mean PM10 levels changed from 41.2 to 38.3 µg/m³ at the traffic station Avenida da Liberdade with considerable ups and down. PM10 exceedances are far above EU limit values of 35 days per year: 82 exceedance days were monitored in 2008 and 79 in 2012. Again, high fluctuations with an intermediate high of 117 in 2011 were registered. In 2014, Lisbon seemed to meet EU limit values for PM10, but meteorological conditions helped a lot for this compliance.

NO2 levels decreased from 64.6 to 58.3 µg/m³ between 2008 and 2012, meaning that Lisbon also breached these EU limit values. NO2 limit values (annual and hourly) did not seem to meet EU limit values in 2014, and there are signs that this trend of non-compliance will continue in 2015.

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Capital of Luxembourg

From 2008 to 2012, the particulate matter exceedance days at the Luxembourg Centre traffic station increased from 3 to 14, with a maximum of 20 exceedance days in between. At the same time, annual mean values of PM10 slightly increased from 18.3 to 21.8 µg/m³. The background station Luxembourg Bonnevoie does not show any exceedance days in the same period. It monitored extremely low concentrations (zero exceedance days since 2010). Here, also the annual mean value for PM10 is relatively low and close to values at the traffic station. Low background concentrations imply that only limited transboundary emissions exist for the City of Luxembourg. Similarly, concentrations at the traffic station can only marginally be further reduced.

Nevertheless, Luxembourg has a major problem with NO2 emissions. These values constantly exceed the EU limitation by about 1.5 times at the traffic station and nearly reach the EU limits at the background station. There is no reduction trend visible since 2006: concentrations slightly fluctuate around 58 µg/m³ at the traffic station and around 37 µg/m³ at the background station.

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Capital of United Kingdom

London experienced a reduction trend of particulate matter between 2005 and 2008 and a further decrease by 2012: PM10 exceedance days at Marylebone Road traffic station decreased from 60 to 27 after an intermediate high of 58 exceedance days in 2011. Accordingly, PM10 annual mean values decreased from 39.1 μg/m3 to 31.1 μg/m3 between 2008 and 2012. PM10 exceedances at Horn Lane, however, increased from 71 in 2009 to 76 in 2013, which shows that London has a very diverse air pollution pattern.

Overall, London has had a trend of 2% per annum reductions in NO2 concentrations in each of the last 6 years. At Marylebone Road station, NO2 concentration decreased from 115.5 μg/m3 in 2008 to 94.3 μg/m3 in 2012, meaning they are far above EU limit values (40 μg/m3).

Other traffic stations like Oxford Street and Brixton Road possibly have the highest officially monitored concentrations of NO2 in the world.

King’s College website on air quality, comment on NO2 concentrations at Oxford Street station (Engl.):…

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Capital of Spain

For PM10 Madrid stays safely under the EU limit values, while it has to be remarked that there is not a healthy threshold level even below these limits.

The air pollution problem for Madrid is NO2. There has been a certain reduction trend although levels have always been above EU limit values. However, NO2 levels in 2014 showed a significant increase and the beginning of 2015 the situation actually deteriorated. Six measuring stations (out of 24) had already exceeded the hourly limit value for NO2 for the whole year 2015 by January the 12th. Therefore, Madrid is far from complying with NO2 limit values.

The situation of economic crisis has caused a significant traffic reduction in Madrid (both private and public transport).

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Capital of Italy

The number of days exceeding limit values for particulate matter PM10 at the traffic station on Corso Francia seems to be fluctuating in recent years. After a big drop between 2008 and 2010 from 77 to 38 exceedance days, values increased again – having an intermediate high of 68 in 2011 – to 57 exceedance days in 2012. Although high infringements of EU regulations were registered for PM10 exceedance days, as only 35 per year are allowed, annual mean values decreased from 40.9 µg/m³ in 2008 to 36.3 µg/m³ in 2012, which means they are better than EU limits. At the same time, NO2 annual mean values decreased from 78.9 µg/m³ to 72.6 µg/m³, far above the EU limits of 40 µg/m³.

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There is no consistent reduction trend concerning daily PM10 exceedances of limit values and only a slight reduction of annual mean PM10 concentrations at the traffic station Sud Lyonnais. PM10 exceedance days increased from 70 to 73 between 2008 and 2012 – after an intermediate high of 95 exceedance days in 2011. At the same time, annual mean values decreased and complied with EU limitations in 2012.

Concentrations of NO2 are far above the annual limit values. Between 2008 and 2012, NO2 concentrations only slightly decreased from 79.2 to 76.7 µg/m³. An intermediate high of 90.9 µg/m³ was monitored in 2010.

Emissions from transport make up a large share of local emissions. In 2012, these were responsible for 70% of NO2 and about 30% of emissions of particulate matter. The Rhône-Alpes region (including Lyon) is subject to an infringement proceeding for not respecting the European ambient air quality legislation due to many exceedances for PM and NOx.

Air Rhône Alpes (Fr.):

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Milan has a serious air quality problem, with levels of both PM10 and NO2 by far exceeding EU limit values. However, in the past couple of years there have been signs of improvement in the city. Between 2009 and 2012, there was a decrease in the number of exceedance days of PM10 at the Milano Verziere station, but it and stagnated at the background station Via Carlo Pascal. Milano Verziere, a not representative traffic station (there is limited traffic in the city centre and within Area C), reported 102 exceedance days in 2009 and – after an intermediate high of 132 – this decreased to 94 in 2012. Annual average concentrations of PM10 also show a small but continuous trend of decreasing values. Between 2009 and 2012, values decreased from 44.1 to 42.4 µg/m³ at the traffic station and from 46.1 to 43.5 µg/m³ at the background station. Similarly, NO2 concentration decreased from 56.6 to 50.9 µg/m³ at the traffic station and from 61.2 to 51.4 µg/m³ (2011) at the background station.

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Capital of France

After an increase of PM10 exceedance days between 2005 and 2009, the city managed to reduce these values. Still on a very high level and far above EU limits, the exceedance days of PM10 at the traffic station Place Victor Basch decreased from 91 in 2009 to 73 in 2013. At the same time, the annual mean decreased from 44.6 µg/m³ to 40.0 µg/m³ and somet EU threshold values in 2013. However, the French yearly quality objective of 30 μg/m³ was not achieved. The background station Paris 18ème reported 22 exceedance days in 2009 and – after an intermediate further reduction to 18 as well as an intermediate high of 29 – 26 exceedance days of PM10 in 2013. Annual mean values decreased from 28.1 µg/m³ in 2009 to 26 µg/m³ in 2013.

A massive problem also remains for NO2: Although a decrease of the annual mean NO2 level was reported between 2009 and 2013 from 96.5 µg/m³ to 81 µg/m³ at the traffic station, this is still more than double the EU threshold values. And also at the background station, NO2 annual mean values are above EU limit values with 43 µg/m³. The new mayor has stated her intent to reduce NO2 by 40% and particulate matter by 28% by 2020 and has incorporated a mix of new measures in her air quality plan to start from July 1, 2015.

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