Simpler methods to bind road dust

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Beryl Ruth Bradford
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1 Simpler methods to bind road dust

2 Operational measures against PM 10 pollution in Stockholm Mats Gustafsson Göran Blomqvist, Sara Janhäll (VTI) Christer Johansson, Michael Norman (SLB-analys)

3 PM 10 ABATEMENT IN STOCKHOLM

4 A history of PM 10 measures in Stockholm Decreased winter sand usage (not evaluated) Congestion charges Street cleaning Dust binding Speed regulations Information campaigns about studded tyres Studded tyre ban

5 Evaluated methods Dust binding with CMA (calcium magnesium acetate) Improved street cleaning techniques

6 10 g/m 2 CMA spread with standard disc spreader

7 Vacuum sweeper High pressure water + sweeping and vacuuming High suction vacuuming

8 Norrlandsgatan

9 Norrlandsgatan

10 Norrlandsgatan

11 Measures : CMA and sweeping on Hornsgatan and Sveavägen : Test streets CMA Vacuum sweeper Flushing Normal operation Hornsgatan X X X X Sveavägen 59 X X X Sveavägen 83 X X Fleminggatan X X X X Reference streets Folkungagatan Norrlandsgatan X X

12 Registrating operational measures

13 Registrating operational measures

14 Number of operational measures Oct 2012 April 2013 Street CMA Salt solution Prewetted salt Vacuum sweeper Flushing sidewalk Hornsgatan Sveavägen Sveavägen Folkungagatan Fleminggatan Norrlandsgatan

15 EVALUATION TECHNIQUES

16 Wet dust sampler (WDS) for road dust sampling

17 Texture and friction RST road surface tester PFT portable friction tester

18 Evaluation methods PM 10 TEOM NO X (NO and NO 2 ) AC31M Road surface wetness at four sites

19 EFFECTS ON ROAD DUST

20 Dust load (DL180) three seasons CMA Reference

21 Dust load (DL180) three seasons CMA Reference

22 g/m2) 0 (g/m2) g/m2) 0 (g/m2) % DL180 (g/m2) DL180 (g/m2) % DL180 (g/m2) DL180 (g/m2) CMA effect on road dust size distribution CMA Hornsgatan Before CMA Reference Folkungagatan Partikeldiameter (µm) Partikeldiameter (µm) Partikeldiameter (µm) Partikeldiameter (µm) Sveavägen 59 Sveavägen Norrlandsgatan Norrlandsgatan

23 0 (g/m2) 0 (g/m2) % DL180 (g/m2) % DL180 (g/m2) CMA effect on road dust size distribution Hornsgatan During CMA Folkungagatan CMA Reference Partikeldiameter (µm) Partikeldiameter (µm) Sveavägen 59 Norrlandsgatan

24 DL10 two seasons

25 DL<180 (g/m2) Pavement surface texture influences dust load Road dust Hjulspår in wheel track MTD (mm)

26 Texture histograms of some Stockholm streets

28 Road surface chemistry

29 Road surface chemistry

30 Friction effects of CMA? Dry Wet Dry Wet

31 EFFECTS ON PM 10

32 Antal dygn över 50µg/m 3 jan-maj Results PM Number PM10, of Antal days dygn exceeding över 50 µg/m 50 µg/m 3, jan-maj 3, Jan-May Folkungagatan Hornsgatan Norrlandsgatan Sveavägen Miljökvalitetsnorm Fleminggatan Michael Norman, SLB-analys

33 Effect of measures on PM 10 on Hornsgatan Road dust days (dry conditions) Vägdammsdagar Ratio treated/non-treated street Förhållande Ho/Fo / / / /2012 städning Previous seasons and nontreated Sweeping (Scrubber) 2011/2012 spolning Flushing 2011/2012 CMA Dust binding CMA

34 Effect of measures on PM 10 on Hornsgatan Hornsgatan/Folkungagatan Road dust days (dry conditions) Hornsgatan/Folkungagatan Ratio treated/non-treated street / / /2012 obehandlade cma städning cma och untreated CMA Sweeping CMA städning Previous seasons (Vacuum) and sweeping

35 µg/m3 NaCl and CMA in PM 10? 1.4 Mean for 27 days in Mar May ,9% av PM Natriumklorid om all klorid är NaCl NaCl if all Cl is NaCl Resten NaNO3 0,14% av PM10 CMA om all acetat är CMA CMA if all Ac is CMA

36 A SEASON ON HORNSGATAN

37 The season at Hornsgatan Precip. Sand up-take Snow Drying up

38 Example of improved operation strategy Extended dry vacuum cleaning during winter Early up-take of winter sand Start CMA and vacuum cleaning as soon as studded tyres are allowed More intense CMA treatment and dry vacuum cleaning until stop of studded tyre use. Also at sub-0 temperatures.

39 TO BE EVALUATED

40 city streets (CMA+vacuum) Transport administration roads (MgCl 2 )

41 Block-wise dust binding Ordinarie CMA-utläggning Utvidgad kvartersvis CMAutläggning Mätplats Sveavägen 59

42 CMA+KF (potassium formate) Tested in EU Life+ project CMA+ A mixture of CMA and KF indicated better friction and better and prolonged dust binding effect in laboratory than clean CMA and KF

43 Conclusions so far Road dust load Road dust depot reaches max in late winter, min in september and late may (during the measurement season) Surface chemistry can be followed and reflects road operation measures. Very sensitive to precipitation Higher road surface texture relates to higher road dust depot Current dose of CMA does not pose a traffic safety risk PM 10 Dust binding works well but the effect is short-lived Sweeping DOES collect PM 10, but the effect on PM 10 concentration is low, unclear or none. Why?

44 Why so hard to see effect of sweeping? Collection of dust mainly from low-emission surfaces (outside wheel tracks)? Re-distribution of dust from low-emission to high emission surfaces and thereby causes higher short-term emissions? Too little dust? Evaluation methods not suitable for long-term effects? Combination of all?

45 Strategies? Current strategy in Stockholm: Priority to reach limit values Dust bindning and vacuum sweeping in all major streets (35) as often as possible when not too humid or cold Potential for optimization!

46 Results PM10 Number of days exceeding 50 µg/m 3, Jan-May Michael Norman, SLB-analys

47 Stockholm reports at See also for more Stockholm air quality reports

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