The problem (and opportunity) of Air Quality in Cities Prof. Paul S. Monks

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 China’s industrial provinces Po valley Shipping routes São 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

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)

AQEG, London, March 20104

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).

AQ - What are the major components?

The Urban Population Exposure The ISSUE, Feb147

The Chains of AQ POLICY IMPACTS e.g.health OBSERVATIONS EMISSIONS

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

Rural Background - Trends The Issue, Feb 1410 Zoe Fleming (ULeic) Weybourne, N. Norfolk.

Some AQ Topics in Brief The ISSUE, Feb1411

Particles Leicester, 23/5/2013-5/6/2013

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.

A transect... Henley upon Thames Southend upon sea

Wood Smoke The Issue, Prevalence of wood burning increasing, (re-)emergent issue in terms of AQ & health

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 in UK (Summer) (VonSchneidemesser et al, 2014)

Aerosols and other AQ agents on climate 17 Air Quality “regulated?” aerosols are the largest factors offsetting greenhouse gas forcing!

‘AIR QUALITY’‘CLIMATE’ 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

Mitigation of Short-Lived Climate Forcers The ISSUE, Feb1419 Shindell et al, 335, 183 Science, 2012

Trade-Offs 20 VonSchneidermesser and Monks, ESPI,15, 1315, 2013

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.

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

THE ISSUE Workshop on Air Quality in Cities M. Petrelli - Roma Tre University February 2014 The evaluation of road traffic emissions

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……….

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

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

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

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

Total daily CO emission at intersections Application in Brindisi network Level of congestion in the road network

Emissions comparison Low congestion in the network – very similar emission values

Emissions comparison Low congestion in one arteria – large difference in emission values

Emissions comparison Low congestion in the network – very similar emission values

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%

Application in Eur Rome network

High congestion in the network – large increase in emission values

Application in Eur Rome network High congestion in the network – large increase in emission values

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

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

Breakout Sessions Feedback from breakout Sessions - Facilitators Conclusions