Transportforum 2010 1

Studies about the effect of street cleaning equipment on PM10

Kaarle Kupiainen, Nordic Envicon Oy

Liisa Pirjola, Metropolia University of Applied Sciences

Jari Viinanen, City of Helsinki

Transportforum 2010, Linköping, 13.1.2010

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Outline of the presentation

• Starting points

• A mobile street surface PM10 emission measurement system in the SNIFFER vehicle

• Street cleaning equipment tests in the KAPU-project– Results– Conclusions

• KAPU-project 2006-2009

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Starting points when considering PM10 and cleaning equipment

• Efficiency of removing suspendable PM10 from street surface– Current equipment is not efficient in removing PM10 on short term (but

not all need to be!)– Dust reducing (PM10) equipment coming in the future?– Street surface emissions vary very much in Nordic conditions (spring

peak)

• Emissions from the equipment during operation should also be considered– Outcoming cleaning air (especially with equipment that operates dry or

”semi-dry”)• There are different filtering technologies and current equipment is not efficient in

reducing PM10

• How about equipment that use much water?

– Exhaust• Euro-standards• Alternative fuels (e.g. CNG or biogas)

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Street cleaning equipment – studies do not report technical details -> often hard to evaluate the results; often different methods are used in combination

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Cleaning equipment tests in the KAPU-project (2006-2009) – the reseach questions

• Does state-of-the-art filtering reduce PM10 emissions in the outcoming air from a mechanical brush sweeping system (Dulevo)?

• How does the cleanings affect street surface PM10 emissions?– Modern state-of-the-art street scrubber– Mechanical brush sweeping system (Dulevo)– Vacuum sweeper

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Street surface PM10 emission measurement method

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Minimizing environmental impact of the equipment during operation - Effect of state-of-the-art filtering (Gore-filter) on PM10-emissions of the Dulevo 5000 *

Research aims in the KAPU-project: 1. To measure the effect of advanced filtering technology (Gore-

filter) on PM10-emissions in the outcoming air2. Measure the effect of cleaning on street surface PM10-

emissions• In 2009 also traditional vacuum cleaner Dulevo 7000 was

tested

* Mechanical brush with slight vacuuming, used frequently in Finland in removing coarse material, e.g. traction sand, from street environments

Equipment

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Dulevo 5000, Evolution (Gore filter)Dulevo 5000, City (regular filter)

Dulevo 7000 traditional vacuum cleaner

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Study location: Viikintie, Helsinki

Traffic lights

Roundabouts

Turning point

Turning point

Measurement speeds

Outcoming air 7-8 km/h

Road surface 40 km/h

1bc1d

2

3

4

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Study location in Spring 2009

0

100

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500

1bc

east

1bc

wes

t

1d

2 3 4

Viik

intie

ave

rage

DN

V In

spec

tion

re

port

Regular

Gore

µg/m3

0

1000

2000

3000

4000

1 2 3 4

Viik

intie

ave

rag

eµg/m3

City (Regular)

Evolution (Gore)

PM10 reduction 94-98%,(Average 95%)

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Results – Dulevo 5000 outcoming air PM10 concentrations

2008 (summer time street surface emission levels):

• Gore-filter reduced the outcoming particle concentrations by 56% in average

• DNV sertification measurements in Italy reduction 48%

2009 (spring dust period):• Gore-filter reduced particle

concentration by about 95%

Gore-filter resulted in reduced PM10 concentrations in the outcoming air from the device

extra cost 2500€ compared with regular fit filter (total cost of the equipment 160 000€)

Less cleaning of the filter required (lower maintenance costs)

August 2008

April 2009

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Efficiency in mitigating street surface PM10 emissions - what does the earlier reasearch say?

• Current cleaning methods effective in removing visible dust and debris and traction sand

• Efficiency decreases towards smaller dust grain sizes • International literature indicates positive efficiencies on:

– suspendable solids (<100µm from street surface): 10 to 50% – street side TSP (RGVS+washing, Chang et al., 2005): 0 to 30%

• Efficiencies to remove PM10 less promising:– street side PM10 (vacuuming, Fitz 1998): no effect– emission potential (vacuuming, Kuhns et al., 2003): no effect– street side PM10 (washing, Lohmeyer et al. 2004): no effect– street side PM10 (washing, Johansson et al. 2005): no effect

• However, cleaning measures remove material that is potentially fragmented to PM10 (Kuhns et al., 2003)

Street surface PM10 emissions in Viikintie in 2009 (Dulevo 5000 and Dulevo 7000)

• Dulevo 5000 mechanical brush with slight vacuuming

• Dulevo 7000 traditional vacuum sweeper

• The equipment did not reduce street surface PM10 emissions

• Traditional brush and vacuum sweeper equipment seem not to be efficient in acute mitigation of PM10 emissions from street surfaces (However, no results from very high dust loads!)

• Beneficial in long term, removes and mobilixes dust forming material from the street environment

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0500

1000150020002500300035004000

east west east west east west east west

Dulevo 5000 Section 1

Dulevo 5000 Section 2

Dulevo 5000 Section 3

Dulevo 7000 vacuum sweeper

SNIF

FER

signa

l (µg

/m3 )

Before cleaning

After cleaning

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Street scrubber equipment

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Modern state-of-the-art street scrubber – Street surface PM10 emissions before and after cleaning in Tikkurila, Vantaa, spring 2008&2009

• Cleanings were done in Vantaa, Tikkurila KAPU-route in March April 2008 and in April 2009

• The route was devided into parts that were cleaned either with

– street scrubber (red line)

– vacuuming (dashed line)

• How did the cleaning affect street surface PM10 emissions?

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2008 results – measured SNIFFER street surface PM10 emissions

02000400060008000

100001200014000

Ratatie, cleaned 1.4.

Talvikkitie, cleaned 1.4. west & 2.4.

east

Tikkurilantie, cleaned 1.4.

Tuupakantie, cleaned 2.4.

& 3.4.

Urheilutie, cleaned 1.4.S

NIF

FE

R s

ign

al (

µg

/m3 )

Streets cleaned with the street scrubber

31.3. 1.4. 2.4. 3.4.

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2000

4000

6000

8000

10000

12000

14000

Talkootie* Talvikkitie* Tikkurilantie*

Street cleaned with vacuuming

31.3. 1.4. 2.4. 3.4.

µg/m3

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2008 results – street surface PM10 emission reductions

• Reductions up to 50% were observed

• Note that the street surface PM10 emission level was very high!

Emission reductionsAfter 1 day After 2 days After 3 days

Ratatie 50 % 51 % 37 %Talvikkitie 42 % 45 %Tikkurilantie 42 % 43 % 59 %Urheilutie 28 % 45 % 4 %

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0 2000 4000 6000 8000 1000012000Before cleaning (µg/m3)

After 0,5-1 days

After 2 days

After 3 days

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er c

lean

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(µg/

m3)

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2009 results – measured SNIFFER street surface PM10 emissions

• Street surface PM10 emission level approximately half of the 2008 level

• Not as clear emission reductions as in 2008

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Rat

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SN

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sig

nal (

µg/m

3) Before

After 1 day

After 2 days

After 3 days

After 4 days

After 5 days

After 6 days

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2009 results – street surface PM10 emission reductions

• Minor reductions were observed on some of the streets but emissions increased on some streets

• Note that the street surface PM10 emission level was significantly lower than in 2008!

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6000

0 1000 2000 3000 4000 5000 6000

Before cleaning (µg/m3)

After 1 day

After 2 days

After 3 days

After 4 days

Aft

er c

lean

ing(

µg/m

3)

Emission reductionsAfter 1 day After 2 days After 3 days After 4 days

Ratatie 46 % 12 %Kielotie 156 % 201 %Tikkurilantie 45 % 9 %Urheilutie 26 % 23 %

Conclusions – street scrubber

• With high road surface emission levels (e.g. Sniffer signal >3500 µg/m3) scrubber showed systematic reductions

• With lower emission levels (1000-2000 µg/m3, close to summertime levels) the results are not as clear

• The street scrubber’s reduction effect is a result of a combined high pressure washing (water penetrates the microstructure of the pavement, removing dust and debris) and subsequent suction of the formed sludge

– Different approach than with traditional vacuuming– Best results need proper operation and maintenance of the equipment (this

applies to all celaning equipment)

• Street scrubber does not solve the spring time road dust problem but may accelerate the reducing PM10 emission trend observed during spring

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Conclusions from equipment

• Vacuuming and mechanical brushing are not efficient methods in reducing street surface PM10 emissions in the short term

• Street scrubber resulted in reductions in street surface PM10 emissions especially in high street dust loads (beginning of spring)

• With lower street dust loads (summertime levels) the street scrubber did not show systematic reductions

• To minimize the environmental impacts of the e.g. mechanical brush sweeping equipment during operation, good and cost efficient solutions exist to reduce the outcoming PM10 emissions from the cleaning equipment (outcoming cleaning air)

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KAPU-project 2006-2009

• Participants and funders:– Research organizations: Nordic Envicon Oy and Metropolia– 7 cities in South/South-Western Finland (Helsinki, Espoo, Vantaa, Tampere,

Turku, Kerava, Riihimäki) – Variation in:

• size (population 28 000-568 000, altogether 1 443 000) • winter maintenance practices (all sanding – sand and salt)

– Other: Ministry of Environment, Helsinki Metropolitan Area Council (YTV), Local and Regional Government Finland, Berner Oy

• Objectives:– New, more efficient equipment for spring cleaning (BAT)?

• Street scrubbers

– Best practices of winter maintenance and dust suppressing?– Mitigation of dust from construction sites

• Both public works and environmental departments had to be involved

– Detailed bookkeeping of street specific winter maintenance measures by the cities

– Specified route that is driven by Sniffer-vehicle

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Thank you!

Kaarle Kupiainen, Ph.D.

Nordic Envicon Oy

Koetilantie 3

00790 Helsinki, Finland

Tel. +358 50 538 2174kaarle.kupiainen@nordicenvicon.fi