Norwegian Dust. Status of roaddust in Norway, and an introduction to the NORTRIP model. Ingrid Sundvor

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1 Norwegian Dust Status of roaddust in Norway, and an introduction to the NORTRIP model Ingrid Sundvor REDUST Seminar 30. September 2014, Viikki, Helsinki

2 Outline Status of Norwegian dust Concentrations PM10 Common measures in Norway Studded tyre use NORTRIP road dust model Concept Application in Oslo Road dust analysis Samples from sweepers Sample from cleaning water.

3 Status

4 PM10 Yearly mean Yearly mean: Typically µg/m³ < 40 µg/m³ «Not a problem» Possible new limit value: 22 µg/m³ Bergen, Oslo, Lillehammer, Stavanger, Trondheim

5 Yearly mean: Sources Using a city scale dispersion model, and latest emission inventory including a version of NORTRIP Road dust the largest single source Bruce R. Denby, Transphorm, 2014 Maybe not the same everywhere..but similar for Stavanger

6 Number of days above 50 µg/m³ EU: 35 allowed Target: 7 «Is a problem» Especially if new limit value: 15 days allowed S O U R C E S?

7 Days above 50 µg/m³:

8 Days above 50: Seasons

9 PM2.5 fraction sources? Wood burning Road dust Mix Road dust

10 General Measures Parking restrictions more expensive, less time, only for residents. More public transport -Gasbuses Entrance Fee, fixed and rush hour Improve conditions for bikes and pedestrians More distric heating plants and financial support for changing woodstoves

11 Road dust measures 1 Cleaning (or better quality) of gravel and sand (mainly used on sidewalks and non-salted roads) More removal of snow from the shoulders /depots More wet cleaning Information Campaignes

12 Road dust measures 2 Reduced Speed limits Oslo; main roads Lillehammer; sentral areas MgCl2 as a dustbinder and in de-iceing salt Studded tyre fee (Oslo and Bergen)

13 Non-studded tyre fractions Oslo and Bergen have a studded tyre fee: 30 kr (3.5 ) for a day, 400 kr (50 ) for a month and 1200 (150 ) for the season. (1. nov-27. april)

14 Effect of fee on non-studded tyre share Non-studded tyre share for Oslo (blue) and Trondheim (yellow) Introduction of fee Trondheim Oslo Removal of fee % 50% % 86%

15 Studded tyres and concentrations

16 Oslo: The success story Speed limit reduction 80 to 60 RV4 More roads Speed limit 70 all year Studded tyre fee reintroduced More cleaning, Dust binding Several measures together have given positive results

17 But Some cities still need to do more measures Which of the measures are most effective? And what about Oslo that already do everything if the limit value get stricter? Authorities want to know the efficiency of their measures and further understand the processes to better mitigate road dust NORTRIP

18 NORTRIP emission model

19 Introduction: NORTRIP model NOn-exhaust Road TRaffic Induced Particle emissions Developed from 2010 at NILU, Bruce R. Denby NORTRIP projects 1 and 2 for co-operation among 9 Nordic institutes The co-operation through NORTRIP has been essential for the model development A process based model

Drainage Spray Cleaning Drainage Spray Ploughing Ploughing Salt Wind suspension Traffic suspension Precipitation Evaporation condensation Traffic turbulence and heat flux The NORTRIP model concept

20 Drainage Spray Cleaning Drainage Spray Ploughing Ploughing Salt Wind suspension Traffic suspension Precipitation Evaporation condensation Traffic turbulence and heat flux The NORTRIP model concept Meteorological conditions Temperature, humidity and radiation Particles TSP PM 2.5 PM 10 Energy balance Wetting Salting Freezing temperature Vapour pressure: evaporation Surface moisture conditions Surface retention Retained wear Sanding Deposition Road surface Sand abrasion Sand crushing Wear road, brake and tyre Direct emissions

21 NORTRIP: 2 coupled submodels Road dust model Road moisture model

22 Application RV

23 RV 4 site location

24 Oslo RV4 detailed information Speed limit reduction 80 to 60 RV4 More roads Speed limit 70 all year Studded tyre fee reintroduced More cleaning, Dust binding

25 RV4: Traffic changes Reduced speed limits (80-60) Studded tyres Traffic changes 14 % speed reduction 23 % studded tyres reduction 4 % reduced ADT

26 RV4:Meteorological variation Salting 2005 dryer: Precipitation almost halved 2006 a bit colder More salting in 2006, 75 tons/km 2006 with MgCl 2 Including 17 events only MgCl 2

27 RV4 2005: Modelled and observed daily means

Modelled source contribution (µg/m 3 ) RV4: Summary results 35 30 25 20 15 10 5 0 NORTRIP model do capture the main changes:

28 Modelled source contribution (µg/m 3 ) RV4: Summary results NORTRIP model do capture the main changes: Source contributions Exhaust Meteorology and traffic changes due to the measures. Salt Brake wear Tyre wear Road wear

29 Sensitivity to meteorology

30 Impact of meteorology: Net mean concentration

31 Impact of meteorology: Exceedances

32 Impact of meteorology Meteorology with associated activites like salting has as much effect as the traffic changes due to year to year changes and the measures of reduced studded tyres and reduced speed. Difficult to assess a measure by observations alone Should be assessed over several years NORTRIP model can help to evidence the changes due to the road dust measures

33 More model developement Increased process understanding NORTRIP 2 Cleaning and sweeping, efficiency and size distributions Wet removal processes, drainage and spray

34 Dust samples from Oslo

35 How «spring cleaning» is done in Oslo

36 Samples in Oslo 3 main dust samples from the sweeper after cleaning 3 different streets in Oslo E6 Ulvenpslitten RV168 RV4 1 water sample

37 Analysis 1) Road dust and water sample analysed by SINTEF and VTI for size distributions. 2) NILU analysed the water sample for soluble ions and cations and non-soluble particle mass per gram water Motivation: NORTRIP Cleaning vs. other processes like drainage and spray More on cleaning and sweepers

38 Size distributions (dust from the sweepers) Of the total samples about 2-8 % of the dust was PM10 < 200 um it was about % PM10 (after sieving) and 4-5 % PM 2.5

39 Size distribution (dust from water sample) ~50 % PM 10 and about 13 % PM2.5 1 gram water contained gram non-soluble particles

40 Size distributions in relation to Traction sand (VTI, 2008): 16 % PM10 (10-20%) From the road surface Stocholm (VTI, 2012): % PM10 From laboratory test on road wear (Snilsberg, 2008) % PM10 Sweepers take up more larger particles.. shoulders are likely to have more gravel /sand larger particles etc??

41 Results ions and cations Cl Na Mg Ca RV168 (µg/g) RV4 (µg/g) Ulvensplitten E6 (µg/g) Vannprøven (µg/ml) Sweeper samples: Little salt 0.2 % of mass. Na/Ca ratio very small Water sample: 30 % of the total particle mass was soluble particles (salts) and mainly NaCl Salt only in the smaller fractions not taken up by the sweepers? Drained before the cleaning day? (Not same days (or road) for the samples)

42 Summary: Dust samples Still open question to the efficiency Sweepers take up more larger particles The salts mainly in the water A lot more to explore on this..

43 Presentation summary 1 Reduced PM10 in some cities, but still too many exceedance days Road dust is one of the main sources of those exceedance days especially in some cities Norwegian National Targets are not reached and possible new limit vaules; so more work to do to reduce levels in all cities. Several measures are in place Lower studded tyre fraction has been a main mitigation strategy MgCl2 commonly used since 2006

44 Presentation summary 2 NORTRIP: a process based road dust emission model Application at RV4 for 3 winters with both traffic and meteorological differences Model captures well these differences Variability due to meteorology as large as the effect of traffic measures NORTRIP model and measurements together gives better understanding

45 Thanks to Bruce Rolstad Denby, MET All partners in the NORTRIP project Karl Idar Gjerstad, Directorate of Public Roads Municipalities: Oslo Trondheim Lillehammer Bergen Thanks to funders: NMR-Nordic Council of Ministers Miljødirektoratet- Norwegian Environmental Agency

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