Session 33 Riekele de Boer

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Transportforum 2010IPL Air Quality Innovation ProgrammeAir Quality alongside motorways

Riekele de BoerCentre for Transport and Navigation

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Rijkswaterstaat

Rijkswaterstaat is the executive agency of the DutchMinistry of Transport, Public Works & Water Management

Mission statement of Rijkswaterstaat:• Keeping Dutch feet dry• Sufficient and clean water supply• Smooth and safe traffic on roads and waterways• Reliable and usable information.

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National Road Network

• 3.260 km motorways (64 national roads)• 710 km noise barriers• 2.533 viaducts, 715 bridges• 16 tunnels• 8 aqueducts• 7 ecoducts• 14.244 signposts• 7.137 km barriers

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Air Quality in the Netherlands

The problem

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Exceedances:

• NO2

– along motorways– in major cities

• PM10

– in major cities– in centre and south

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National Air Quality Cooperation Programme (NSL)

European, national AND local measures needed Cooperation Ministry VROM with other ministries,

provinces and municipalities

Aims:• Public health• Spatial projects• Comply with

European standards (‘derogation’)

Innovation Programme Air Quality (IPL)

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IPL Air Quality Innovation Programme

• 2005 – 2010• 20 Million €• 9 large scale field trials• 3500 meetings • 60.000 hours members IPL team

12 final reports with English summary

IPL

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Aim: identify, develop and test local measures that can contribute to improve air quality along motorways

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Partnerships

• Government: Ministry of Transport, Ministry of Environment, local authorities

• Private sector: consultants, contractors

• Knowledge institutes: national and international scientific community

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IPL

Six directions of potentially promising measures

• Canopies and air treatment• Dynamic traffic management• Roadside vegetation• Road cleaning• Catalytic Coating• Noise barriers

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IPLDirection 1: Canopies and air treatment

• Improving air-quality near highway’s in densely populated areas

• light-weight canopies • Requirements

– Structurally sound– Safe and sustainable

• High costs

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• Air pollution near tunnels a potential bottleneck• Passive and active dispersion techniques• Passive techniques

– Smart canopies: emissions are diluted or diverted by enhanced natural ventilation, multiple ventilation slits or a stack

• Active techniques– Mechanical ventilation and in-stack air-treatment – High costs and large ecological footprint

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• Electrostatic Concept: active air technique • Particulates > 10 nm are positively charged• Deposit on a grounded gauze• Test were conducted in the Thomassen Tunnel on the A15• Max 15% reduction in vehicle related particulates• After optimization a higher reduction efficiency is expected

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IPLDirection 2: Dynamic traffic management

• DTM: measure to improve traffic flow and reduces congestion and improves air quality as a favourable side effect

• DTM in the Netherlands• Dynamax: Optimizing traffic flow by Dynamic

maximum speed • Rerouting the heaviest polluters like lorry traffic• Forecasting conditions favouring bad air quality

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• Dynamax test at the A1 (Bussum-Muiderberg)– Aim is to reduce annual average NO2 concentration– Continuous monitoring of the traffic intensity by

means of induction coils in the tarmac – Adaptation of the speed-limit to stay below the

congestion threshold intensity– Traffic information by means of VMS (Variable

Message Sign)

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Empirical test at the A58 (Goirle-Tilburg)– Aim is to reduce the number of day’s the daily PM10 limit

is exceeded– KNMI warns when weather conditions favouring high

particulate concentrations are forecasted.– RWS reduces the speed-limit from 120 km/h to 80 km/h

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IPLDirection 3: Roadside vegetation

• The effect of vegetation on air quality is not completely clear.– Vegetation is clamed to reduce pollution levels due to

filtering action– Vegetation affects wind speed causing pollution

concentrations to increase

• To gain understanding in the effect of vegetation on air quality two flied trail were conducted– At the A50 near Vaassen a measurement campaign was

carried out on existing roadside vegetation– At the A50 near Valburg a measurement campaign was

carried out on specially planted vegetation

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• Flied trails– PM10 and NO2 meteorological parameters– Simultaneous measurements on patches with and without

vegetations to asses the vegetation effect– Type of vegetation, coniferous or deciduous

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• Results– Direct along side the motorway pollution levels increase

slightly– On moderate distances (50-100 m) a positive effect is

found • Conclusion

– Vegetation is an un-effective measure in order to meet the threshold levels according to the regulations

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IPLDirection 4: Road cleaning

• Road cleaning: a measure to prevent the resuspension and enhance deposition of dust by wetting the road surface

• International trails suggest that road cleaning has beneficial effect on PM10 levels.

• In the IPL program several trails and modifications of road cleaning are investigated– In Nijmegen the effect of wetting is studied in relation to

porous asphalt concrete (PAC) en dens asphalt concrete (DAC)

– On the A50 south of Apeldoorn 3 methods cleaning motorways are tested. 2 dry methods and 1 spaying wet road salt (CACl2)

– An extensive trail on the A73 near Malden applying wet CaCl2.

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• Wet cleaning of PAC in Nijmegen showed non significant positive effect compared to DAC (the observation period was short and the effect was small compared to the measurement errors)

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• CaCl2 spraying: – CaCl2 is used to extend the duration of the wetting effect

because it attracts and binds moisture. – Test on the A73 show that the wetting effect remains

more than 48 hours.– CACl2 spaying reduces the total PM10 concentration by

over 10% and the PM10 road contribution by 20% to 30%

y = 0.81x

-5

0

5

10

15

-5 0 5 10 15

PM10-road contribution (m 1) [μg/m3]

PM

10-r

oad

co

ntr

ibu

tio

n (

m 2

) [μ

g/m

3]

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IPLDirection 5: Catalytic coating

• Laboratory test have show that TiO2 and clean stone convert NO and NO2 in aqueous nitrate.

• During IPL program field test are conducted to find out if noise barriers coated with TiO2 or made from clean stone show a higher NO2 reduction potential

• Field tests were conducted along the A1 at Teschuur and along the A28 in de “Proeftuin” at Putten

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• Field test A1 at Teschuur– 4 panels with different TiO2 coating were tested

– No significant decrease of the NO2 concentrations were measured.

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• Field test A28 at Putten– During a period of 3 months a noise barrier coated with

TiO2 and a porous noise barrier were tested

– No significant decrease of the NO2 levels were measured

• Explanation– Short contact time between exhaust gasses and barrier– Meteorological conditions, wind speed & direction– Low temperature, low radiation level, high humidity

• Conclusion– No evidence is found that coated noise barriers show an

improved performance towards the deduction of NO2

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IPLDirection 6: Noise barriers

• Along the A28 at Putten a Barrier test-site “De Proeftuin” was erected in 2007

• A 4 m noise barrier as reference and 8 other noise barriers were tested in periods of 3 months

• Amongst these were innovative designs and coated barriers.

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Arrangement of the test-site “De Proeftuin”

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Impression of the measurement equipment

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• Result – 4 m reference barrier

– Advanced barriers to improve contact time or turbulent mixing like the T-top, do not perform better than the reference barrier.

714NO2

34PM10

1320NOx

Average impact 28.5m [%]

Average impact 10m [%]

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Schematic situation

Wind direction

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IPLFacts and figures test site noise barriers

2 local authority 1 amenity area

0 complaints of citizens

1200 meters road made of chopped branches

23 entries for the competition

8 winners of the competition

1 Minister

9 barriers tested of which 6 from contractors 1 stone through the

glass screen

5 measurement rounds of 3 months each

918 meter of tested noise barrier

13 measurement set up

55 measuring instruments

5 drenched laptops

10 km cable

11000 watt

Many men with dog

11.000 measuring hours of which 1.750 useful measurements

4 damped ditches

700 filters

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Final Remarks

• IPL has yielded a vast amount of knowledge

• Many results are ready for use 12 final reports with English summary

• Some topics need further research

• IPL has ended work on air quality along motorways continues

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Final Remarks1: Content

• Big research effort on air quality and roads

• Large scale test sites

• High quality measurements and data-analysis

• PM10 difficult to measure

• Measurement vs. Modelling

• Lab-experiments vs. practical experiments

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Final Remarks1: Content

+Barriers

-Catalytic coatings

+Road surface

+/-Vegetation

+/-DTM

+Canopies and air treatment

Relevance of measures studied:

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Final Remarks2: procedures

• IPL: extra measures with limited effect (‘end of pipe’)

• Therefore, focus on source measuresand cooperation between governments

⇒ ‘IPL paradox’

Date post:	05-Jul-2015
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Session 33 Riekele de Boer

Technology