2. Study overview
3. CAZ considerations
4. CAZ areas
5. Emissions and AQ impacts – screening
6. More detailed modelling
7. Conclusion and thoughts
• England’s fastest growing large city
• Increase in population
• = Increase in road traffic
– Increase in congestion
– Increase in emissions
– Increase in PM, NO2, CO2
– Unless modal shift…
– Or zero emission vehicles
Greater Manchester 2040 vision
GREATER MANCHESTER LOW-EMISSION STRATEGY
AND AIR QUALITY ACTION PLAN
• EU/UK NO2 limit/objective value – exceedance
• Feasibility study
to look at road
• WP1 – Screening
• WP2 – Refining of air quality estimates
• WP3 – Refine economics ?
• WP4 – Refine health ?
• WP5 – Reporting ?
Undertaken through work packages:
CAZ Considerations Description Importance
Administrative boundary Where is the CAZ boundary? The location of the CAZ boundary is important
both in determining potential benefits and in order
to determine the potential costs and enforcement
Class (vehicle types) Which CAZ class should apply? I.e. what vehicles
will be restricted within the CAZ boundary (and
subsequently people and businesses)? Which
vehicles will be exempt from meeting the CAZ
standards when within the CAZ boundary?
Which CAZ class is used affects both the
potential benefits that can be derived from the
CAZ and also effects the enforcement costs and
other socio-economic impacts.
Standards What should the minimum standards for a CAZ
be? Defra have used Euro V/6 (diesel) and Euro
4 (petrol LDV) standards for different CAZ
The standards that are targeted will affect the
actions taken to meet the CAZ requirements, with
lower standards more likely to result in vehicle
replacement by some (lower costs) but with
Hours of operation When will the CAZ standards need to be adhered
There are different implications from a full-time
CAZ compared to a peak-time or a day-time CAZ
Daily charge How much would people / businesses have to
pay to enter the CAZ boundary where their
vehicle is affected and does not meet the CAZ
The level of charge is important as it catalyses
the users’ decision making and impacts the level
of benefits and costs of the CAZ
Enforcement and costs How will the CAZ standard be enforced within the
CAZ boundary e.g. manual or camera?
Depending on the location and the class of the
CAZ the enforcement options are different, but
they have implications on the potential cost and
the likely derived benefits
Potential CAZ areas being considered
1. Manchester city centre
2. Inside the M60
3. Segregated zones based on poor AQ
How do you define the boundary?
• To model a CAZ you need to define
a boundary – a line
• AQMA (red)?
• NO2 exceedance area in 2020?
• Political boundary?
• Saturn model boundary (e.g.
• Buffer zone?
• Physical boundary – public
• How do you reach consensus?
• GETAGREEMENT EARLY!
Vehicle class and Euro standard
• Note – various cities across Europe have LEZ’s which include combinations of
above, including cars (e.g. Germany, Lisbon)
A Buses, coaches, taxis (Euro 6/VI)
B Buses, coaches, taxis and HGVs (Euro 6/VI)
C Buses, coaches, taxis, HGVs and LGVs (Euro 6/VI diesel
and Euro 4 petrol)
D Buses, coaches, taxis, HGVs, LGVs and cars (Euro 6/VI
diesel and Euro 4 petrol)
Air quality benefit area city centre & M60 (road rel)
Screening Conclusions (WP1)
• Class D outperforms other CAZ options for both
concentrations and emissions (as expected)
• Class A has more limited NOx improvement.
• Limited potential for improving PM10 – not just
related to emissions but brake and tyre wear
• NOx road emission and concentration road
contribution % reduction are broadly similar
(though this could vary at street level – fleet mix).
• Results for all 3 CAZ areas are broadly similar in
terms of % NOx road emissions reduction.
Air quality dependant on:
– Traffic flow data
– Fleet – e.g.. % of HDV
– Proportion of diesel
– Age of vehicles
– Estimated vs. real-world emissions?
• Primary NO2
• Test cycles
– NOx to NO2 conversion
– Other sources
How to refine AQ modelling (WP2)?
WP2 – Age and diesel proportions
• Worked with GMP,ANPR data from cameras on key routes into city
• Had to be anonymised
• Used neutral week
• 2.5 million records per year processed!
• Key parameters: fuel type, vehicle types, number plate (anonymised)
Traffic flows, % splits and emissions
• Age/petrol/diesel per vehicle type rollover model – but is this really
• Non-CAZ compliant vehicles replaced (ULEZ) with compliant
• Saturn used for various cost scenarios (£1 upwards) – at £5 became
cost sensitive - rerouting.
• Results used to calculate emissions – using appropriate Euro fleet
• Emissions fed into dispersion model along with other sources and
results outputted for all scenarios.
• Primary NO2 and NOx emissions used
• Other sources used within ADMS-Urban and background
• NOx to NO2 conversion within ADMS used to calculated
• Fleet mix and NO2?
– Defra NOx to NO2 assumes certain fleet mix proportions
– Sensitivity of pNO2
• Electric proportion - more brake & tyre wear?
• What are the timescales?
Months 2 3 4 5 6 7 8 9 10 11 12
Analysis & report
• How can a CAZ be used to affect modal shift?
• How will a CAZ impact on vehicles outside the
• How will modal shift impact on health (e.g. more
active lifestyle & lower emissions)?
• How did we all get here today? – Will this change
in the future and what would make you change?