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Evaluation of measures for airpollution abatement in
Pamplona, SpainFernando Martín, José Luis Santiago,
Rocío Alonso, Yolanda Lechón, Esther RivasCIEMAT, Spain
David Elustondo, Jesús SantamaríaUniversity of Navarra, Spain
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Index
• LIFE – RESPIRA project• Effect of urban vegetation on air quality.
– Experiments in streets and with vegetation barriers– CFD simulation (street, district and vegetation barriers)– External cost (health)
• Effect of photocatalytic pavements on air quality:– CFD simulation– External cost (health)
• Effect of traffic rearrangements:– CFD simulation– External cost (health)
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
LIFE-RESPIRA project 2014-2017 Participants: Universidad de Navarra, CIEMAT, GANASA General objective: Assessment of cyclists and pedestrians exposure to urban air pollution. Some specific objectives:o High resolution modelling of urban air quality.o Quantifying and modelling the effect of urban vegetation on urban air quality.o Quantifying and modelling the effect of some air pollution abatement strategies in an urban area.o Quantifying health impacts.
200.000 inhabitants
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Investigating effect of urban vegetation
• Experiments in street canyons.– Two streets. One with trees and other without
trees.– Simulations with CFD model.
• Experiments in roads crossing urban parks:– Effect of trees– Effect of shurbs hedge in the sidewalk– Simulations with CFD model.
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
11,7m
6,8m
3,4m
Tafalla st
Effect of street trees on air pollution dispersion
San Fermín st
3,8m
6,5m
10m
Field campaignsPamplona
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Tafalla st, no trees
Effect of street trees on air pollution dispersion
San Fermín st, with treescalm (76%) wind
calm (42%) wind
-8% -19% -5% -19% -10% -19%
-5% -10% -6% -8% -2% -21%
a a ba a b a b c
a b ca
b b a a b
Trees reduce upward transport of
vehicle emissions and increase air
pollution within canopy
19 July- 2 August 2016, Field experimentsbl
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TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Vegetation tunnel
Effect of street trees on air pollution dispersion
Main objective:Estimate effect of street vegetation on air quality taking into account two importantaspects: Dynamical effects (modifying air flows, turbulence and ventilation) Removal effects (vegetation is a sink of air pollution by deposition).
Studied: How do trees affect NOx distribution in an urban dictrict at pedestrian level? What happen if trees are planted in the free-tree street?
Effect of street trees on air pollution dispersionModel simulations
Effect of street trees on air pollution dispersionCFD simulations
NOx (LAD=0.5) – NOx(LAD=0.1) (µg m-3)
• What happens if the foliage is more dense (increasing Leaf Area density, LAD)?• What happens if the deposition velocity of pollutants captured by trees increases?• Several high resolution CFD-street canyon modelling for a dominant wind direction(NNW) and for several scenarios of deposition velocity and LAD• Aerodynamics (dispersion) effects seem to dominate over deposition effects.
Scenario with new trees in Tafalla streetReal case
Calle Tafalla
What happens if trees are planted in a tree-free street?High resolution CFD-street canyon modelling for a dominant wind direction (NNW)
Effect of street trees on air pollution. CFD simulations
Effect of street trees on air pollution dispersionCFD simulations
Real case
Newvegetationscenario
NOx (RealCase) – NOx(NewVeg) (µg m-3)
LAD=0.5 m-1; vdep= 1 cm/s
The inclusion of new trees in one street modifiessignificantly pollutant distribution not only in thatstreet, but also in nearby streets.Global effects in pollutant concentration are small
What happens if trees are planted in a tree-free street?High resolution CFD-street canyon modelling for a dominant wind direction (NNW)
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Concentration-response functions
WHO, 2013. Health risks of air pollution in Europe – HRAPIE projectRecommendations for concentration–response functions for cost–benefit analysis of particulate matter, ozone and nitrogen dioxide
External Cost (health) of mitigation measures.Effect of street trees on air pollution dispersion
We were focused on NO2
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Monetary valuesHolland, M. Cost-benefit Analysis of Final Policy Scenarios for the EU Clean Air Package.Version 2. Corresponding to IIASA TSAP Report11, Version 2a October 2014
Updated for inflation to 2015 prices
Monetary value Unit
Mortality 68,143.70 € Euro2015/life year lost
Bronchitis in children 694.43 € Euro2015/case
Respiratory hospitaladmissions
2,621.82 € Euro2015/case
External Cost (health) of mitigation measures.Effect of street trees on air pollution dispersion
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
What happens if trees are planted in a street without trees?
High resolution CFD-street canyon modelling + concentration-response functions+ monetary valuation
External Cost (health) of mitigation measures.Effect of street trees on air pollution dispersion
Group A* (pollutant-outcome effects for which enough data are available for a reliable quantification)Group B* (pollutant-outcome effects for which there is more uncertainty) effects are quantified.
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Ave. Navarra
Experiments in streets crossing urban parks:Effect of shurbs hedge in the sidewalkBlack carbon
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of shurbs hedge in the sidewalk. Field ExperimentsBlack carbon
Avenida Navarra, deciduous (9/March/2017)
10:00 11:00 12:00 13:00 14:00 15:00 16:00
RoadDistanceVegetationng/m3
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Black carbon
Vegetal barriers are effective for
reducing air pollutant exposure
Calm(v<0.5 m/s)
-29% -30%
bab
Road Distance Vegetation
27/June/2017
Road Distance Vegetation
From road(SW)
Road Distance Vegetation-26% -37%
bab
Parallel to road(NW/SE)
Road Distance Vegetation
-26% -36%
bab
-27% -35%
ng/m
3 ba
b
Effect of shurbs hedge in the sidewalk. Field experiments
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of vegetation (shrubs/trees) barrier. CFD simulations
New York, USA 6-10August 2018 18
EvaluationExp./CFD Wind direction BC Concentration Reduction
PercentageBlue point Green point
(P1)Exp. 0°±30º 20.0% 44.3%
CFD0° 26.5% 44.6%
45° 21.5% 46.1%-45° 31.9% 45.1%
P2P1
P3 NOVEGETATION BASE
NEW_TREESNO_TREES
Hedgerow (He) Tree T Tree_small TsHeight (He_H) = 1 m Horizontal dimensions (T_hd)
= 6 m x 3 mHorizontal dimensions (Ts_hd)
= 2 m x 2mWidth (He_W) = 0.8 m Base (T_b) = 2 m Base (Ts_b) = 2m
LAD (He_LAD) = 4.29 m2 m-3 Top (T_t) = 10 m Top (Ts_t) = 4 mLAD (T_LAD) = 0.5 m2 m-3 LAD (T_LAD) = 0.5 m2 m-3
Actual vegetation barrier characteristics
Average reduction P3: 46%
Average reduction P3: 61%Average reduction P3: 11%
b) c)
d)
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
New York, USA 6-10August 2018
Hypothetical vegetation barrier scenarios:
19
Average reduction of taller-hedge + trees vs NO_VEGETATION below thetree base at P3 = 59% (16% for taller hedge and without trees)
Average reduction of wider-hedge + trees vs NO_VEGETATION below thetree base at P3 = 65% (24% for wider hedge and without trees)
Average reduction of taller-wider-hedge + trees vs NO_VEGETATION belowthe tree base at P3 = 66% (33% for wider hedge and without trees)
Effect of vegetation (shrubs/trees) barrier. CFD simulations
Taller hedge
Wider hedge
Taller andwider hedge
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of photocatalytic pavements. CFD simulations
2016 NO2 annual average concentration
Assumptions:o Photocatalytic pavement (only sidewalks)
400m x 400m around Plaza de la Cruz square.o Always is photactive and deposition velocity
(applied to NO2) 0.5 cm/s (In real case, ithappens only in daytime).
Compared with base scenario withoutphotocatalytic materials.
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
o Relative differences of averagedconcentrations around 2% in thephotocatalytic area.
o However, model assumptions areoverestimating the photocatalyticeffect.
Effect of photocatalytic pavements. CFD simulations
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of photocatalytic pavements.External Cost (health)
1%
2% Effect of photocatalyticpavements in sidewalks
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of traffic rearrangements. CFD simulations
2016 NO2 annual average concentration
Scenarios (BASE+12new scenarios):Restriction zones (Z1 and Z2)6 scenarios per zone, combination of:o Traffic inside restriction zone reduced to:
o 0% (no traffic)o 20% (few traffic)
o Traffic increases around restriction zone:o 0% (no traffic divertion),o 30% (some traffic divertion),o 60% (important traffic divertion)
Z1
Z2
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of traffic rearrangements. CFD simulations
(% ) = (Z2E0060 – BASE)/BASE*100 (% ) = (Z2E0000 – BASE)/BASE*100
(% ) = (Z2E2000 – BASE)/BASE*100(% ) = (Z2E2060 – BASE)/BASE*100
No traffic inside, strong traffic divertion No traffic inside, no traffic divertion
Few traffic inside, strong traffic divertion Few traffic inside, no traffic divertion
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Effect of traffic rearrangements. External costs
-22%
-58%
+5%+4%
TFIAM Workshop on local measures to improve air quality and health,Tallinn, 28-29 June 2018
Conclusions
• Trees reduce dispersion of traffic emissions in streets and increase airpollution within canopy
• Aerodynamics (dispersion) effects seem to dominate over depositioneffects.
• The inclusion of new trees in one street modifies the distribution ofpollutant, not only in that street, but also in nearby locations, but totaleffects in pollutant concentration and health cost savings are smallDO NOT BLAME THE TREES! Traffic has to be removed from streets!
• Vegetal barriers are effective for reducing air pollutant exposure,especially when combined hedges and trees forming wide barriers.VEGETAL BARRIERS CAN ISOLATE PEDESTRIANS FROM ROAD TRAFFIC!
• Effect of photocatalytic pavements is negligible.• Redistribution of traffic in the city might produce important reductions in
air pollution and health impacts but only if there are no significant trafficdivertion