Ambient Air Quality Refer to Section 2.5 of the Guidance Note
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Application Form for the European Green Capital Award 2019 5. Ambient air quality Refer to Section 2.5 of the Guidance Note 5A. Present Situation Indicator Unit Year of data Max Number of days per year on which EU target 0 Days 2015 value for ozone was exceeded (8h mean) Number of ozone No of monitoring stations 2 monitoring 2015 stations Max Number of days per year on which EU target 26 Days 2015 value for PM10 was Hjortnes, road side exceeded (24h mean) Number of PM10 No of monitoring stations 11 monitoring 2015 stations PM10 - Max 24 concentration recorded (max annual mean) ug/m3 2015 Hjortnes, road side Number of NO2 No of monitoring stations 10 monitoring 2015 stations NO2 - Max concentration 53 recorded (max annual mean) ug/m3 2015 Smestad, road side NO2 - Annual Average Urban background concentration stations: Grønland: 27 Breivoll: 27 Road side stations: Kirkeveien: 35 ug/m3 2015 Alnabru: 43 Manglerud: 42 RV 4 Aker: 31 Smestad: 53 Bygdøy allé: 51 Hjortnes: 44 Åkebergveien: 31 Number of PM2.5 No of monitoring stations 10 monitoring 2015 stations PM2.5- Max concentration 9 3 ug/m 2015 recorded (max annual mean) 1 Application Form for the European Green Capital Award 2019 PM2.5- Annual Average Urban background concentration stations: Sofienbergparken: 9 Breivoll: 8 Road side stations: Kirkeveien: 9 ug/m3 2015 Manglerud: 8 Bygdøy allé: 8 Alnabru: No data Hjortnes: 9 RV 4 Aker: 7 Smestad: 8 Åkebergveien: 8 Systematic air quality monitoring over many years Air quality monitoring began in Oslo in the 1950s. The number of monitoring stations has been steadily growing over the years. The current configuration of 4 background stations and 8 roadside stations in Oslo’s urban area (figure 5.1) has been in operation since 2014. The regional background for ozone is measured at a site to the west of Oslo, in the municipality of Bærum, whilst PM and NO2 are monitored at the Norwegian Institute for Air Research’s station at Birkenes in southern Norway. Air quality in the urban background is generally good, despite the use of wood burning stoves being common in certain areas of the city. Oslo’s urban background has complied with the ambient air quality directive since its implementation, with the exception of two years (2010 and 2011) when the limit values for hourly and annual mean for NO2 were exceeded. Figure 5.1: Overview of air quality monitoring stations in Oslo (2013). One of the current urban background stations, Breivoll, was established in 2014 and is therefore not included on the map. Orange lines indicate roads with reduced speed limits – see section 5B, below. 2 Application Form for the European Green Capital Award 2019 Compliance, improvements and challenges Ozone levels are well under the EU target value because of rapid, local break down by the NO component of NOx emitted from road traffic. Ozone generating photochemical reactions on the other hand, are much slower and may occur over a larger area. Oslo’s first air quality action plan resulted in a significant improvement in the number of exceedances of the daily mean value for PM10. Since 2007, the levels have, in general, complied with the EU Directive’s limit value of maximum 35 exceedances per year (figure 5.2). The only exception to this is in 2013, when the limit value was exceeded at one of the monitoring stations. The reasons for the exceedance in 2013 are complex. However, a main factor was unusually dry weather, limiting the effects on the available abatement measures. The EU Directive’s limit value for the annual mean concentration of PM10 has not been exceeded at any monitoring station in Oslo in the past decade. This may be explained by approximately 60-70 % of PM10 pollution arising from sources which are confined to the winter months, i.e. wood burning and road wear from studded winter tyres. In addition, meteorological conditions, which lead to temperature inversions and high levels of pollution, are also confined to the winter months. Similarly, PM2.5 concentrations are primarily influenced by combustion emissions, which are most significant during the winter months. Therefore, it is the low summer contributions to the concentrations of PM10 and PM2.5, which attenuate the annual mean values, leading to compliance. The annual mean concentration of NO2 has remained relatively stable for a number of years (figure 5.3), despite the widespread introduction of catalytic converters to petrol cars. This is a consequence of the increased proportion of diesel vehicles with high emissions of NOX/NO2. The EU limit value is exceeded, especially along roads with heavy traffic. In periods of temperature inversions in the winter months, the EU limit value for hourly mean concentrations of NO2 is also exceeded, especially along roads with heavy traffic (figure 5.4). The weather conditions strongly affect the number of exceedances per year. 60 Kirkeveien R 50 Alnabru R 40 Manglerud R Skøyen U 30 Rv 4 Aker R Sofienbergp. U 20 Bygdøy allé R Smestad R Number of exceedances 10 Hjortnes R Åkebergveien R 0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Breivoll U Year 3 Figure 5.2: Number of days per year the daily mean value for PM10 (50 µg/m ) was exceeded in the period 2005-2015. The red line indicates the EU Directive’s requirement of maximum 35 exceedances p.a. R=Road-side; U=Urban background. Source: City of Oslo and Norwegian Public Roads Administration 3 Application Form for the European Green Capital Award 2019 80 70 Grønland U 3 60 Kirkeveien R 50 Alnabru R Manglerud R 40 Bygdøy allé R 30 Hjortnes R Åkebergveien R Concentration, µg/m 20 RV 4 Aker R 10 Smestad R 0 Breivoll U 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year 3 Figure 5.3: Annual mean concentration of NO2 (µg/m ) in the period 2005-2015. The red line indicates the EU Directive’s limit value of 40 µg/m3. R=Road-side; U=Urban background. Source: City of Oslo and Norwegian Public Roads Administration 250 200 Grønland U Kirkeveien R Alnabru R 150 Manglerud R Bygdøy allé R 100 Hjortnes R Åkebergveien R Number of exceedances 50 RV 4 Aker R Smestad R 0 Breivoll U 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year 3 Figure 5.4: Number of hours per year the mean value for NO2 (200 µg/m ) was exceeded in the period 2005-2015. The red line indicates the EU Directive’s requirement of maximum 18 exceedances p.a. R=Road-side; U=Urban background. Source: City of Oslo and Norwegian Public Roads Administration 4 Application Form for the European Green Capital Award 2019 Contribution from long-range transport The contribution from long-range transport to the annual mean concentration of nitrogen oxide and particulate matter was estimated in 2014 in Oslo’s air quality action plan (5D1). The contribution to NOx is relatively small, at just 12 %, whilst the contributions to PM10 and PM2.5 are significantly higher, at 44 % and 56 %, respectively. Factors and constraints Oslo is located in a bowl formation in the terrain, the city centre being surrounded by hills to the north and the Oslo Fjord to the south. At times, large areas of the city may be affected by poor air quality during the weather phenomenon known as temperature inversion. Prolonged inversions occur generally within the coldest months, i.e., the period of December to February. The combination of Oslo’s bowl shaped topography, and a cold layer of air trapped under a warm layer, leads to poor air exchange. This in turn leads to increased levels of air pollution. Winters in Oslo are cold and snowy with average temperatures around - 4°C. Winter air quality is therefore affected by the prevalence of emissions from heating appliances, as well as increased emissions from cold starting of vehicles. In addition, studded winter tyres, which are used to improve traction on icy roads, have the disadvantage of increasing wear on bare asphalt compared with non- studded alternatives. Figure 5.5: Winter weather in Oslo showing a temperature inversion episode. The share of diesel cars increased from 9 % to 46 % in the period 2004-2015. The increase has arisen as a consequence of the Norwegian government’s change to the one-off vehicle registration tax, in order to favour vehicles with lower CO2 emissions. In real traffic, the emissions of NOX from diesel cars are high, especially in cold weather. In addition, diesel cars have a higher direct emission of NO2 than petrol cars. The relative contributions to total NO2 emissions in Oslo are 54 % and 3 %, respectively. A number of national trunk roads pass directly through the city (e.g., the motorways E6 and E18, see figure 5.1) and road traffic emissions contribute significantly to air pollution. Population growth in the Oslo area is considerable, having increased by 30 % since the year 2000, leading to increased economic activity and environmental pressures, including air pollution. In the summer months, the air quality in Oslo is in general good. The favourable meteorological conditions in the summer months, with typical unstable air masses rapidly dilute emissions. The urban heat island effect on air pollution is not a significant factor. 5 Application Form for the European Green Capital Award 2019 5B. Past Performance – Oslo on the way to Zero Emissions Managing Air Quality Oslo has a third-generation action plan (5D1), following requirements in the EU Air Quality Directive. The action plan was adopted by the City Council in 2015 (5D2) and is actively followed-up (5D18).