The problem (and opportunity) of Air Quality in Cities Prof.
Paul S. Monks
Slide 2
Nitrogen dioxide (NO2) is an important ingredient in the
formation of air pollution. This map shows the global distribution
of tropospheric NO2 as observed from 2005 to 2008 by the Ozone
Monitoring Instrument (OMI). Various sources of air pollution can
clearly be distinguished: traffic, heavy industry, fossil fuel
power plants, biomass burning, oil refineries, and shipping routes.
OMI was built by The Netherlands and Finland and is onboard NASA's
Aura satellite. Paris Biomass burning Johannesburg Highveld area
Buenos AIres Mexico City Chinas industrial provinces Po valley
Shipping routes So Paulo Santiago Moscow Western Europe Riyadh Oil
sands production Melbourne Sydney Urumqi Air pollution low NO 2
high NO 2 Power plants New Delhi U.S. East coast San Fransisco Los
Angeles Cairo Pearl river delta Tokyo Tehran Chicago more data and
information can be found at www.temis.nl
Slide 3
Air Quality Around 90 % of city dwellers in the European Union
(EU) are exposed to one of the most damaging air pollutants at
levels deemed harmful to health by the World Health Organisation
European Environment Agency (October 2013)
Slide 4
AQEG, London, March 20104
Slide 5
What is the impact of Air Quality? AQ has implications for a
number of contemporary issues including: Human health, (e.g.
respiratory, cancer, allergies), Eco systems (e.g. crop yields,
acidification / eutrophication of natural ecosystems), National
heritage (e.g. buildings), Regional climate (aerosol and ozone
exhibit a strong regionality in climate forcing).
Slide 6
AQ - What are the major components?
Slide 7
The Urban Population Exposure The ISSUE, Feb147
Slide 8
The Chains of AQ POLICY IMPACTS e.g.health OBSERVATIONS
EMISSIONS
Slide 9
Where are we now? 9 a) Emission Trend (total UK) Air Pollution:
Action in a Changing Climate; March 2010 b) Birmingham centre The
ISSUE, Feb14
Slide 10
Rural Background - Trends The Issue, Feb 1410 Zoe Fleming
(ULeic) Weybourne, N. Norfolk.
Slide 11
Some AQ Topics in Brief The ISSUE, Feb1411
Slide 12
Particles Leicester, 23/5/2013-5/6/2013
Slide 13
13 High PM 2.5 concentrations are frequently associated with
air transported into the UK from continental Europe. Urban
background PM 2.5 concentrations are dominated by regional rather
than local sources, PM from sources in continental Europe, probably
as secondary PM, significantly affects concentrations in the
UK.
Slide 14
A transect... Henley upon Thames Southend upon sea
Slide 15
Wood Smoke The Issue, 201415 Prevalence of wood burning
increasing, (re-)emergent issue in terms of AQ & health
Slide 16
Changing emissions and ozone The Issue, Feb 1416 Difference map
for O 3 concentrations (units are g m -3 ) in Paris change with
zeroed out traffic emissions (Pandis et al., 2010).Pandis et al.,
2010 Change in ozone 2008-1998 in UK (Summer) (VonSchneidemesser et
al, 2014)
Slide 17
Aerosols and other AQ agents on climate 17 Air Quality
regulated? aerosols are the largest factors offsetting greenhouse
gas forcing!
Slide 18
AIR QUALITYCLIMATE Halo Carbs Trop O 3 Black Carbon Aerosols
(direct + indirect) CO 2 CH 4 N4ON4O AQ 18 Parsing out the forcing
agents Could climate goals be achieved, at least partially, by non-
climate treaties? Factors other than climate are also of major
concerns regarding these forcing agents AQ and climate policies
& their impacts need to be examined together and based on sound
scientific knowledge Ravishankara (NOAA) AQ or Climate
Slide 19
Mitigation of Short-Lived Climate Forcers The ISSUE, Feb1419
Shindell et al, 335, 183 Science, 2012
Slide 20
Trade-Offs 20 VonSchneidermesser and Monks, ESPI,15, 1315,
2013
Slide 21
Seven Facts from the 2013 Year of the Air (EEA) 1.More than 9
out of 10 city-dwellers in Europe are exposed to air pollutants
above World Health Organisation guidelines 2.Air pollution
legislation is not always fully implemented 3.Cutting air pollution
may also help address climate change 4.In 2011, several EU Member
States breached legal limits for air pollution, mostly for nitrogen
oxides (NOx). Traffic is one of the main sources of NOx. 5.A
growing body of scientific evidence suggests air pollution is more
harmful than previously thought. 6.Air pollution also has an
economic cost to society. 7.Many cities are taking positive steps
to cut air pollution.
Slide 22
Summary Air pollution harms human health and the environment
Much success in reduction of emissions and general improvement in
air quality in Europe. The air quality problem persists especially
in cities Many of the pollutants have a complex regional and local
interplay PM 2.5, NO 2 and ozone (hemispheric) The ISSUE,
Feb1422
Slide 23
THE ISSUE Workshop on Air Quality in Cities M. Petrelli - Roma
Tre University February 2014 The evaluation of road traffic
emissions
Slide 24
1.Model for emissions estimation in large scale urban network
Urban network congestion Large scale city (not single arterial)
with relatively low calibration & computational cost/time
taking into account different time slices (time variability) taking
into account queue phenomena 2.Evaluation of traffic management
impacts from emissions point of view Traffic management such as
arterial signal optimization (cycle, phases, offset), ramp
metering, one-way system, reversible lanes, ITS solutions and so on
optimum for traffic (generalized cost/time) optimum for emissions
Real time estimation Which evaluation and why.
Slide 25
State of the Art Two main approaches: Microscopic (USA) based
on the evaluation of driving phases of a vehicle (acceleration,
steady state, deceleration) Macroscopic (EU) based on computation
of specific vehicle emission factors, average vehicles speed and
distance travelled 1)Macroscopic model based on v, k, q (CORINAIR)
reference model for estimating emissions in Europe [Lumbreras et
al.; European Environment Agency] in congested network, usually
macroscopic models underestimate emissions [Shukla-Alam;
Rakha-Ding; Rouphail et al.] 2) Microscopic model based on v i, a,
d, delay (MOVES) mainly useful for emission estimation in arterials
or single intersection [Stevanovic et al.] good results in arterial
or single intersection optimization [Midnet et al.; Coelho et al.;
Rakha et al.] Traffic model (congestion) Emission model Dispersion
model
Slide 26
Proposed approach Estimation of pollutant emissions in a large
area network with a suitable level of accuracy Possible use of the
model: Offline for planning Real Time for control MICRO (approach)
MICRO (approach) MACRO (approach) MACRO (approach) MESO (approach)
MESO (approach) Mesoscopic: DTA (Dynamic Traffic Assignment) Large
area road network 24 h analysis Realistic emissions estimation
Slide 27
New Model for emission estimation The idea is to divide each
link in 3 different parts: LA - vehicles are at free-flow speed LB
- vehicles are in queue LC - vehicles are in acceleration phase
Post processor module: Model for queue assessment + Assessment of 3
different emission factors
Slide 28
The model has been applied to the city of Brindisi (100K
inhabitants) Traffic flows have been simulated from 5 am to 23 pm
884 links 306 nodes 14 signalized intersection Application in
Brindisi network
Slide 29
Total daily CO emission at intersections Application in
Brindisi network Level of congestion in the road network
Slide 30
Emissions comparison Low congestion in the network very similar
emission values
Slide 31
Emissions comparison Low congestion in one arteria large
difference in emission values
Slide 32
Emissions comparison Low congestion in the network very similar
emission values
Slide 33
Impact evaluation of different policies VKTVHD Av. Speed
CONOxPM10 a- -- --- b-1%-5%3%-2% c -13%7%-15%-11% d0% -3%0%
b+c-4%-19%12%-14%-12%-11% b+c+d-3%-17%10%-13%-11%-10%
Slide 34
Application in Eur Rome network
Slide 35
High congestion in the network large increase in emission
values
Slide 36
Application in Eur Rome network High congestion in the network
large increase in emission values
Slide 37
Model Layout Meso-simulation model (Dynameq) has been used to
evaluate traffic congestion and related traffic flow parameters
CORINAIR has been used to evaluate the specific vehicle emissions
Dispersion model has to be developed to estimate air pollutants
dispersion Need of dispersion model and data for model
validation
Slide 38
Breakout Sessions Optimal use of road traffic and travel data
Roland Leigh Lecture Theatre Promotion of multimodal journeys Josh
Van Hey Bell Restaurant Uptake of public transport Marco Petrelli
Bell Restaurant Improving emissions using alternative fuels Teresa
Murdoch Room Local Government Policy Craig Brown Brunel Room
Slide 39
Breakout Sessions Feedback from breakout Sessions -
Facilitators Conclusions