Effectiveness of air quality measures in Stockholm

Effectiveness of air quality measures in Stockholm Christer Johansson Department of Environmental Science and Analytical Chemistry Stockholm university & Environment and Health Administration Stockholm

Climate combat District heating Clean cars Congestion tax Public transport Clean water Waste treatment Recycling Clean air Green areas Noise reduction

Sweden first to be condemned by European Commision court due to exceedances of PM10 together with Slovenia in 2010

Very high daily mean PM10 on Hornsgatan (the 36th highest mean should not exceed 50 ug/m3)

Source contributions PM10 non-exhaust road traffic Ultrafine PM, NOx, BC diesel vehicle exhaust + some residential wood burning LDV exhaust All road traff. Power plants HDV exhaust Sea traffic Residential

AQ measures evaluated in Stockholm Low emission zone (diesel exhaust) Extended low emission zone (to be evaluated) Congestion tax (exhaust+non-exhaust) Extended and raised congestion tax Non-exhaust (PM10) measures Dust binding Studded tyre ban Vehicle speed regulations Alternative pavements 2016-05-23

Low emission zones in Sweden since 1996 Environmental ZONES = Dense residential areas with many pedestrians, cyclists, & sensitive green areas MOTIVATION -Reduce emissions -Improve air quality (NO 2 ) -Reduce noise -Encourage use of cleaner vehicles County of Stockholm Environmental zone ~10 km 1.5 million inhabitants

Swedish rules (HDV+buses) Mix of age and Euro-standard First year of registration According to general rule Euro III (MK2000) Euro IV (MK2005) Euro V+EEV (MK2008) Euro VI or cleaner All fuels No sticker required Retrofitting possible Manual control Penalty 100 Euro

Impact on PM exhaust emissions for year 2000-38% No zone 2000 Zone 2000 Full zone 2000

Reductions in concentrations of NO2 & PM-exhaust NO 2 PM-exhaust up to 1.5% up to 9% PM-exhaust only a small fraction of total PM10

With compared to without zone 2008 Younger truck fleet compared to vehicles registered in Stockholm County Calculated emissions reductions: NOx 3-4 % HC 16-21 % PM-exhaust 13-19 % Large uncertainties regarding emission estimates Real-world emissions much higher than HBEFA CRT s & SCR s not working properly in urban areas 2016-05-23

Stricter future LEZ alternatives to be assessed In addition to current HDV restrictions: 1. LDV at least Euro 5 2. LDV at least Euro 6 3. LDV at least Euro 6c (Real Driving Emissions) 4. Zero emission zone in city center 5. Zero emission zone in city center + ban on studded tyres 2016-05-23

Congestion tax in Stockholm regarded as a success story - Trial 2006 - Referendum 2006 - Permanent from 2007 - Increased and extended tax from 2016-15% 2006: Total: Pass. cars LCV Trucks Buses -15% -17% - 15% -8% +18% Queueing time was reduced by one third in the morning and by half during afternoons (trial)

Current tax: Automatic number plate recognition 1 to 3.5 Euro for every passage Max 11 Euro per day Also foreign vehicles pay >30 stations with APNR

100 000 more inhabitants but no increase in traffic

Nitrogen oxides & exhaust particles 2006 Year 2006 µg/m 3 Increased levels Decreased levels Urban background (roof level, city centre) ~6% decrease ~ 1-2% increase Street level (city centre) ~5-10% decrease Higher levels at Essingeleden bypass and the tunnel exits of Southern Link, ~1-2%

Health benefits of congestion tax in Stockholm using NOx as indicator Nafstad et al. 8 % increase in mortality per 10 µg/m3 NOx

Health benefits using NOx as indicator Reduction in population weighted exposure with congestion tax - 0.23 µg/m 3 25 to 30 fewer premature deaths per year (1.44 million people) 206 years of life per 10 years per 100 000 inhab Effects on mortality tip of the iceberg (less illnesses, allergies, acute effekts etc.)

No tax Tax City stations: NOx -5-13% CO -11-24% PM10-14-20% Exempted bypass: NOx +7% PM10 +-0% NOx CO PM10 Mean conc, weekdays 06-19, year 2005-2008

Effects of increased and extended tax Very small effects % of population: NOx Reduced 32.5% Unchanged 67% (<0.1 ug/m3) Increased 0.5% PM10 Reduced 9% Unchanged 91% Increased <0.1% 2016-05-23

Thousand passages per day Personbilar i trafik Conclusions - Congestion tax 600 500 400 300 200 100 0 Trial Reduced traffic Permanent jan-05 jul-05 jan-06 jul-06 jan-07 jul-07 jan-08 jul-08 80 000 70 000 60 000 50 000 40 000 30 000 20 000 Etanol Fordonsgas El & elhybrid Bränslesnål diesel* Bränslesnål bensin* 10 000 Reduced emissions 0 2001 2002 2003 2004 2005 2006 2007 2008 År 1% 3% 6% 9% Improved air quality Improved health

Efficiency of measures to reduce Non-exhaust PM10 emissions Tyres (studded, non-studded) Dust binding Vehicle speed Street cleaning Traction sanding and salting Pavements (Traffic measures) 2016-05-23

The NORTRIP model NOn-exhaust Road TRaffic Induced Particle emissions SMHI Aarhus University Department of Environmental Science Funded by Nordic Council of Ministers

Modelled compared to observed PM10 Hornsgatan Studded tyre ban introduced 2010 Norman et al 2016. Modelling road dust emission abatement measures using the NORTRIP model: Vehicle speed and studded tyre reduction. Atmospheric Environment, 134, 92-108 2016-05-23

PM10 depends strongly on road surface wetness! PM10 Hornsgatan 2009, Monthly average 160 140 120 High PM10-levels only when streets are dry Dry streets Wet streets PM10 µg/m 3 100 80 60 40 20 0 jan f eb mar apr maj jun jul aug sep okt nov dec

Dust loading Concentration PM 10 concentrations: uncoupled model without retention Modelled Observed R 2 = 0.04 Does not account for the cold wet period OK when dry and little suspension Underestimates spring concentrations No accumulation of dust 23.05.2016

Dust loading Concentration PM 10 concentrations: observed moisture used for retention Modelled Observed R 2 = 0.83 Correlation with PM 10 indicates the quality of the surface condition calculations 27 23.05.2016

Dust binding

Dust binding in central Stockholm performed nov- april every year 42 kilometers Calcium magnesium Acetate solution (CMA) Total cost of measure: ca 1.5 million Euro per year 2016-05- 23

Tests of dustbinding of a highway Vallsta 200 Example from highways test with CMA PM10 µg/m 3 150 100 CMA treated Untreated 50 0 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00 Reduced PM10-concentrations during 24 h with ~35 % along a highway Reduced PM10-concentrations during 24 hours with 5-20 % i the city Reduction in PM10 during a few hours up to 40-70 % Not enough to reach the Limit values in the City Causes friction loss Expensive

Conclusions Efficiency of the low emission zone have decreased since it was introduced Stricter regulations needed to improve efficiency in the future Real-world emissions need to be measured The congestion tax system Trial changed opinion from negative to positive Still ca 20% to 25% less traffic in city center Important reductions in air pollution related heath effects The ANPR efficient for enforcement control Dust binding most efficient for reducing road dust suspension In the long term share of studded tyres need to reduced 2016-05-23

Thank you for listening Christer.Johansson@aces.su.se michael.norman@slb.nu