Auckland Air Emissions Inventory 2016 – Transport (Revised)
Surekha Sridhar and Jayne Metcalfe
March 2019 Technical Report 2018/016-2
Auckland air emissions inventory 2016 – transport (revised)
March 2019 Technical Report 2018/016-2
Surekha Sridhar Jayne Metcalfe Emission Impossible Ltd
Auckland Council Technical Report 2018/016-2
ISSN 2230-4525 (Print) ISSN 2230-4533 (Online)
ISBN 978-1-98-858940-4 (Print) ISBN 978-1-98-858941-1 (PDF)
This report has been peer reviewed by the Peer Review Panel.
Review completed on 20 July 2018 Reviewed by two reviewers
Approved for Auckland Council publication by:
Name: Eva McLaren
Position: Manager, Research and Evaluation (RIMU)
Name: Matt Hope
Position: Manager, Hydrology and Environmental Data Management (RIMU)
Date: 21 March 2019
Recommended citation Sridhar, S and Metcalfe, J (2019). Auckland air emissions inventory 2016 – transport (revised). Prepared by Emission Impossible Ltd for Auckland Council. Auckland Council technical report, TR2018/016-2
Note
This report corrects errors in the calculation of road dust (PM10 and PM2.5) from unsealed roads (Section 6.1) and replaces the version published in July 2018, Auckland Council technical report, TR2018/016.
© 2019 Auckland Council
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Executive summary
Air emissions inventories are a critical component of managing air quality and need to be updated regularly to gauge how emissions are tracking in the region. There were many changes in the transport sector over the last decade in the Auckland region, and while these changes have seen positive results, they are being offset by the rate of growth in the region. Future growth will add more pressure and demand on existing infrastructure, resources, goods and services. An update of the air emissions inventory is therefore necessary to assess how the changes in Auckland region have impacted on emissions in the region, and to measure progress towards the Auckland Plan target (Auckland Council, 2012). This report estimates annual emissions to air from transport in the Auckland region for the year 2016 from motor vehicles, aviation, rail, road dust (sealed and unsealed), off-road vehicles and road laying1 for the following ambient air pollutants:
particulate matter measuring less than 10 micrometres in diameter (PM10)
particulate matter measuring less than 2.5 micrometres in diameter (PM2.5) oxides of nitrogen (NOx) carbon monoxide (CO)
carbon dioxide (CO2)
sulphur dioxide (SO2) volatile organic compounds (VOCs).
Estimates were made using the best available activity data and emission factors for each source, and the associated uncertainty of the emissions estimates. Annual estimates of total emissions across the Auckland region in 2016 for the seven pollutants are approximately:
45,185t/yr CO (91% motor vehicles, 4% lawn mowers, 3% aircraft)
3,930kt/yr CO2 (81% motor vehicles, 12% aircraft, 7% off-road vehicles) 15,286t/yr NOx (67% motor vehicles, 17% aircraft, 15% off-road vehicles)
1,991t/yr PM10 (51% unsealed road dust, 32% motor vehicles, 9% off- road vehicles)
940t/yr PM2.5 (63% motor vehicles, 18% off-road vehicles, 11% unsealed road dust)
1 A separate shipping and ports inventory is available and is not included here. See Auckland air emissions inventory 2016 – sea transport. Auckland Council technical report, TR2018/017
Auckland air emissions inventory 2016 – transport (revised) iv 196t/yr SO2 (62% aircraft, 37% motor vehicles) 4,024t/yr VOCs (80% motor vehicles, 6% off-road vehicles, 6% road laying).
Emissions from unsealed road dust were estimated to account for 51 per cent of
PM10 emissions across the Auckland region and 12 per cent of PM10 emissions within the Auckland Urban Airshed. These estimates are based on very limited local information and are highly uncertain. Further work is recommended to improve the estimation of PM10 emissions from unsealed road dust. Fuel consumption was also estimated. Comparison of estimated on-road motor vehicle fuel consumption with regional fuel sales figures suggests that the inventory may underestimate emissions from motor vehicles by at least 20 per cent. Improving emissions and fuel consumption estimates from the inventory and the vehicle emissions prediction model (VEPM) is recommended as a priority for future research.
Auckland air emissions inventory 2016 – transport (revised) v Acknowledgements
Many individuals and organisations contributed to the successful completion of this project. The project team would like to acknowledge: KiwiRail for supplying freight and GIS data. Todd Ballance (Auckland Transport) for supplying motor vehicle data and assistance through the course of the project. Janani Thilakarathne and Elizabeth Parker (Auckland Transport) for providing spatial and traffic data on unsealed roads. NZ Transport Agency for supplying speed data for unsealed roads in the region. Dr Shanju Xie, Air Quality Scientist at Auckland Council.
Auckland air emissions inventory 2016 – transport (revised) vi Table of contents
Acknowledgements ...... vi 1.0 Introduction ...... 1 1.1 Content and structure of this report ...... 4 1.2 Changes in this version of the report ...... 4 2.0 Method ...... 5 2.1 Estimation of emissions ...... 5 2.2 Estimation of uncertainty ...... 5 3.0 Motor vehicles ...... 9 3.1 Methodology ...... 9 3.2 Results ...... 12 3.3 Uncertainty ...... 20 4.0 Aviation ...... 27 4.1 Methodology ...... 27 4.2 Results ...... 32 4.3 Uncertainty ...... 34 5.0 Rail ...... 36 5.1 Methodology ...... 36 5.2 Results ...... 40 5.3 Uncertainty ...... 41 6.0 Road dust ...... 43 6.1 Unsealed road dust ...... 43 6.2 Road surface wear (sealed roads) ...... 49 7.0 Off-road vehicles and lawn mowers ...... 51 7.1 Off-road vehicles ...... 51 7.2 Lawn mowers...... 57 7.3 Results ...... 58 7.4 Uncertainty ...... 60 8.0 Road laying ...... 62 8.1 Methodology ...... 62 8.2 Activity data ...... 62 8.3 Results ...... 63 8.4 Uncertainty ...... 64 9.0 Overall results and uncertainty ...... 65
Auckland air emissions inventory 2016 – transport (revised) vii 10.0 Conclusions and recommendations ...... 68 11.0 References ...... 70 Appendix A Summary tables – annual emissions estimates ...... 74 Appendix B Daily motor vehicle emission estimates for 2016 ...... 79
Auckland air emissions inventory 2016 – transport (revised) viii 1.0 Introduction
Air quality is affected by emissions discharged into the air. Air pollution causes adverse health effects such as asthma, lung and heart conditions. In order to further improve air quality, we must reduce air emissions. Auckland Council is responsible for the management of air quality in the Auckland region. A suite of strategic plans and statutory regulations require the council to ensure ambient air is clean and healthy to breathe:
The Resource Management Act 1991
The National Environmental Standards for Air Quality 2004
The Auckland Plan 2018
The Auckland Unitary Plan. An air emissions inventory identifies and quantifies sources of air pollution and their trends. It is used to:
determine major sources of air pollutants
assess if emissions have improved, remained the same, or deteriorated over the reporting period
evaluate progress towards the emissions reduction target
provide input for air pollution dispersion and exposure modelling
inform the efficacy and efficiency of mitigation measures and policy initiatives and strategies. The main sources of air pollution in Auckland are from transport, domestic sources and industrial discharges. This report compiles an inventory of air emissions from transport within the Auckland Council boundaries for 2016. The inventories for home heating (Metcalfe et al., 2018), sea transport (Peeters, 2018) and industry (Crimmins, 2018) are reported separately. A summary report is in preparation to integrate these inventories to present an overall picture of air emissions and trends. Detailed emissions inventories are powerful tools for policy and science analysis. For example, the Auckland air emissions inventory has been used to assess likely exposure, health effects of air pollution and costs and benefits of mitigation for various policies (Nunns, 2015). It has also been used to estimate background air quality concentrations (at the census area unit level), for assessment of resource consent applications (Auckland Council, 2014a).
Auckland air emissions inventory 2016 – transport (revised) 1 The Auckland air emissions inventory was last updated in 2014 for the base year of 2006 (hereafter referred to as the “2006 inventory”) and estimated that emissions from the transport sector contributed towards 38 per cent of total annual particulate matter less than 10 micrometres in diameter (PM10) and 79 per cent of nitrogen oxide (NOx) emissions (Auckland Council, 2014a). However, over the last decade, Auckland Council and the Government have invested significant resources towards improving Auckland’s motorways, arterials and local roads, and public transport services and infrastructure. While these changes have seen positive results, they are also offset by the rate of growth in the region. In 2016 Auckland’s population (1.6 million) was almost 18 per cent higher than 2006 and is projected to be 2.3 million by 2043 (Statistics NZ, 2017). This future growth will add more pressure and demand on existing infrastructure, resources, goods and services. An update of the air emissions inventory is therefore necessary to assess how the changes in the Auckland region have impacted on emissions in the region, and to measure progress towards the Auckland Plan target (Auckland Council, 2012):
“reduce pollutant emissions (PM10) by 50% by 2016 (based on 2006 levels) in order to meet national and international ambient air quality standards and guidelines, and achieve a further 20% reduction by 2040” This report estimates emissions to air in the Auckland region for the year 2016 from the transport sector. Figure 1-1 maps the spatial extent of the region for the purposes of this inventory, and Table 1-1 lists the ambient air pollutants and specific transport sources included in this inventory.
Auckland air emissions inventory 2016 – transport (revised) 2 Auckland Urban Airshed
01020 Kilometres
Figure 1-1: Spatial extent of the Auckland region
Table 1-1: Pollutants and transport sources covered in this inventory2
Pollutants Source Particulate matter <10µm in diameter Motor vehicles (PM10). Aviation Particulate matter <2.5µm in diameter Rail (PM2.5). Road dust (sealed and unsealed) Oxides of nitrogen (NOx) Off-road vehicles Carbon monoxide (CO) Road laying Carbon dioxide (CO2)
Sulphur dioxide (SO2) Volatile organic compounds (VOCs)
2 Emissions from shipping are not included in this report and are assessed in a separate shipping inventory. See, Auckland Air Emissions Inventory 2016 – sea transport, TR2018/017
Auckland air emissions inventory 2016 – transport (revised) 3 Emissions are estimated with the best available information and reported at the annual level. This assumes an even temporal distribution of emissions throughout the year. Emissions are also backcast for 2001, 2006 and 2011, and projected for 2026, 2036 and 2040 to provide an indicative analysis for trends, as there is significant uncertainty in the projected estimates except for motor vehicles.
1.1 Content and structure of this report
Section 2 of this report outlines the overall methodology for the estimation of emissions from transport as well as the uncertainty associated with these emission estimates. The subsequent sections provide detailed methodology, results and estimated uncertainty for each source category:
motor vehicles (Section 3)
aviation (Section 4)
rail (Section 5)
road dust (Section 6)
off-road vehicles and lawnmowers (Section 7)
road laying (Section 8). Overall results and uncertainty are summarised in Section 9.
1.2 Changes in this version of the report
This revised report corrects errors in the calculation of road dust (PM10 and PM2.5) from unsealed roads. The updated and corrected methodology is described in Section 6. This report replaces the earlier version published in July 2018 (Sridhar and Metcalfe, 2018).
Auckland air emissions inventory 2016 – transport (revised) 4 2.0 Method
This section outlines the overall method for estimation of emissions from transport sources as well as the methodology for estimation of uncertainty. The detailed methodology and assumptions for each source category are described in the sections that follow.
2.1 Estimation of emissions
Emissions are calculated by multiplying activity data by an emission factor associated with the activity. Activity data is a quantity of an activity that results in emissions during a given period of time (for example vehicle kilometres travelled in a year). Activity data and emission factors come from a variety of sources and are described for each source category in the subsequent sections of this report.
2.2 Estimation of uncertainty
The European emission inventory guidebook (hereafter referred to as the EMEP/EEA guidebook) (EEA, 2016) suggests that emissions inventories should include a first order uncertainty assessment. The EMEP/EEA guidebook states that it is not necessary to get a precise estimate for the uncertainty of each parameter and each value in the inventory. A reasonably rough characterisation of uncertainties can provide a reasonable estimate of the overall inventory uncertainty and can identify the parameters that are most important for the overall uncertainty.
2.2.1 Definition of uncertainty
Uncertainty is reported in accordance with the EMEP/EEA guidance which states: Uncertainty in activity data and emission factors are equal to half the 95 per cent confidence interval divided by the mean and expressed as a percentage. The reason for halving the 95 per cent confidence interval is that the value corresponds to the familiar plus or minus value when uncertainties are loosely quoted as ‘plus or minus x per cent’. Where uncertainty is highly asymmetrical, the larger percentage difference between the mean and the confidence limit is reported.
Auckland air emissions inventory 2016 – transport (revised) 5 2.2.2 Method for determining uncertainty
The EMEP/EEA guidebook describes two tiers for uncertainty analysis (EEA, 2016): Tier 1: estimation of uncertainties by source category using simple equations to aggregate errors. Tier 2: estimation of uncertainties by source category and in the overall inventory by stochastic simulation (Monte Carlo analysis). A Tier 1 assessment of uncertainty was undertaken for this 2016 inventory. To provide a quantitative assessment of uncertainty, it is necessary to quantify the uncertainty in activity data and emission factors. For this assessment, quantitative estimates of uncertainty were based on best available information including:
New Zealand specific data when available.
Published data from international literature, including the EMEP/EEA guidebook.
Where quantitative data were unavailable, estimates were based on expert judgement. For some sources, the default uncertainty ranges provided in the EMEP/EEA guidebook were used. The basis for uncertainty assessment of each key source is described in the corresponding section of this report.
2.2.2.1 Tier 1 default uncertainty ranges
In many cases, quantitative uncertainty data are not available. In these cases, the EMEP/EEA guidebook suggests default uncertainty ranges for emission factors as shown in Table 2-1.
Auckland air emissions inventory 2016 – transport (revised) 6 Table 2-1: Default error ranges associated with emission factors
Typical error Rating Descriptions range
An estimate based on a large number of measurements made at A 10 to 30% a large number of facilities that fully represent this sector
An estimate based on a large number of measurements made at B a large number of facilities that represent a large part of the 20 to 60% sector
An estimate based on a number of measurements made at a C small number of representative facilities, or an engineering 50 to 200% judgement based on a number of relevant facts
An estimate based on single measurements, or an engineering D 100 to 300% calculation derived from a number of relevant facts
An estimate based on an engineering calculation derived from Order of E assumptions only magnitude
(Source: EEA, 2016)
2.2.2.2 Method for aggregating uncertainties
The EMEP/EEA guidebook provides two rules for combining uncorrelated uncertainties under addition and multiplication. 1. Rule A: where uncertain quantities are to be combined by addition:
⋯ Equation 1 ⋯
Where:
xi are the quantities.
Ui are the percentage uncertainties associated with the quantities (half the 95% confidence interval).
Utotal is the percentage uncertainty in the sum of the quantities (half the 95% confidence interval divided by the total (i.e. mean) and expressed as a percentage).
Auckland air emissions inventory 2016 – transport (revised) 7 2. Rule B: where uncertain quantities are to be combined by multiplication:
⋯ Equation 2
Ui are the percentage uncertainties associated with the quantities (half the 95% confidence interval).
Utotal is the percentage uncertainty in the product of the quantities (half the 95% confidence interval divided by the total and expressed as a percentage). These rules are based on the assumptions that variables are uncorrelated with a standard deviation of less than about 30 per cent of the mean. The EMEP/EEA guidebook recognises that in practice these assumptions are often not valid, but states that under these circumstances the rules may still be used to obtain an approximate result.
Auckland air emissions inventory 2016 – transport (revised) 8 3.0 Motor vehicles
Motor vehicles are a significant source of emissions in the Auckland region. The 2016 inventory estimates emissions from motor vehicles using traffic data from the Auckland Regional Transport (ART) model and emission factors from the Vehicle Emission Prediction Model (VEPM).
3.1 Methodology
Emissions were calculated for each vehicle type and each road segment (referred to as road links) in the Auckland region in grams per day as follows:
E EFxVKT Equation 3
Where: E = Emission of a pollutant for each road link (g/day), EF = Emission factor of the pollutant by speed for vehicle type (g/km), VKT = Vehicle kilometres travelled by vehicles on each road link (km).
Road links are the spatial representation of actual road segments in the ART model and have associated traffic and speed data. Speed based emission factors were calculated in VEPM by vehicle type. These emission factors were then applied to the traffic data for each road link to estimate emissions.
3.1.1 Activity data
The Auckland Regional Transport model version 3.2 (ART 3.2) provides traffic data for almost 15,000 individual road links in the Auckland region. The ART model outputs provide spatial allocation of vehicle kilometres travelled (VKT) for three time periods of the day:
AM: 7am-9am (morning peak), IP: 11am-1pm (inter peak), PM: 4pm-6pm (evening peak). And include:
speed; and proportion of light and heavy vehicles, where o Light vehicles = <7.5t, o Heavy vehicles = >7.5t.
Auckland air emissions inventory 2016 – transport (revised) 9 The light to heavy vehicle split was further broken down based on the default fleet provided in the VEPM (version 5.3) as shown in Table 3-1.
Table 3-1: Overall motor vehicle fleet split in the 2016 inventory (derived from ART 3.2 and VEPM 5.3)
ART model Vehicle type breakdown Proportion Fuel vehicle type for this 2016 inventory of fleet Light vehicle Car Petrol 67.0%
Light vehicle Light commercial Petrol 3.3%
Light vehicle Hybrid and electric Petrol 0.7%
Light vehicle Car Diesel 7.7%
Light vehicle Light commercial Diesel 14.0% Heavy Commercial (HCV) Heavy vehicle Diesel 1.3% 3.5t-7.5t Heavy Commercial (HCV) Heavy vehicle Diesel 5.6% >7.5t Heavy vehicle Bus Diesel 0.3%
Total petrol (% of VKT) 71.1%
Total diesel (% of VKT) 23.1%
The ART model does not include data for hours outside of the periods stated above (i.e. hours outside AM, IP and PM). Daily emissions were therefore calculated using an expansion factor which was applied to interpeak VKT as follows:3
VKT AM IP x ExpF PM Equation 4
Where:
VKT24hr = Daily total VKT (km/day), AM = VKT for two hour morning period, IP = VKT for two hour interpeak period, ExpF = Expansion factor for light and heavy vehicles, PM = VKT for two hour evening period.
3 Personal comms. T Ballance, Auckland Transport, 7 July 2017.
Auckland air emissions inventory 2016 – transport (revised) 10 3.1.1.1 2001, 2006 and 2011 traffic data
The ART model base year is 2013 and does not include data for earlier years. To accommodate trend analysis, traffic data from Auckland Council’s Future trends in motor vehicle emissions in Auckland report (Auckland Council, 2014b) was used for 2001, 2006 and 2011.
3.1.1.2 Projections
The ART model includes projections for future years, specifically for 2026, 2036 and 2046. Each year includes a business as usual projection and an alternative scenario projection referred to as an indicative package as recommended for the Auckland Transport Alignment Project (ATAP).4
Table 3-2: Total daily VKT and VKT for heavy and light vehicles (2001- 2040)
Total VKT Light (<7.5t) Heavy (>7.5t) Year (million km/day) (million km/day) (million km/day) 2001 27.5 26.0 1.5
2006 31.6 29.9 1.7
2011 31.8 29.8 2.0
2016 35.2 33.1 2.1
2026 42.3 39.5 2.7
2036 46.4 43.2 3.2
2040* 47.8 44.5 3.3
* VKT interpolated between 2036 and 2046 from ART 3.2.
3.1.2 Emission factors
The Vehicle Emission Prediction Model (VEPM) is an average speed model which predicts emission factors for the New Zealand fleet under typical road, traffic and operating conditions. The latest version, VEPM 5.3, is currently the best tool available in New Zealand to predict motor vehicle emissions in regional inventories, but the model does not include evaporative emissions. VEPM was updated in March
4 ATAP is a joint project involving Auckland Council, the Ministry of Transport, Auckland Transport, the NZ Transport Agency, the Treasury and the State Services Commission, which sets out a direction for the development of Auckland’s transport system over the next 30 years.
Auckland air emissions inventory 2016 – transport (revised) 11 2017 to include the latest fleet data, updated country of origin assumptions, updated emission factors and NO2 emission factors (Metcalfe and Sridhar, 2017). Emission factors were generated from VEPM 5.3 for each year and for:
all speeds between 10 and 99 kilometres per hour5 all vehicle types (Table 3-1)
• all pollutants in the inventory (except SO2).
3.1.2.1 Sulphur dioxide
Sulphur dioxide emission factors were calculated in accordance with the methodology described in the vehicle emission prediction model version 3.0 user notes (Kar et al., 2008). These emission factors are based on the sulphur content in diesel and petrol for the inventory year (Table 3-3) and were applied to the speed- based fuel consumption data from VEPM to derive SO2 speed-based emission factors. Petrol was assumed to be 80 per cent regular and 20 per cent premium petrol (MBIE, 2017).
Table 3-3: Sulphur content in petrol and diesel in 2001 to 2021
Fuel sulphur content (ppm) Year Petrol (premium) Petrol (regular) Diesel 2001 500 500 3,000 2006 150 150 150 2011 50 50 10 2016 50 50 10 2021 10 10 10
3.2 Results
PM10
The 2016 inventory estimates PM10 emissions from motor vehicles to be 647t/yr in
2016. Diesel exhaust emissions account for 73 per cent of motor vehicle PM10
5 Emission factors for speeds >99km/hr are assumed to be the same as for 99km/hr.
Auckland air emissions inventory 2016 – transport (revised) 12 emissions, and petrol exhaust accounts for eight per cent (Figure 3-1). The remaining
19 per cent of PM10 emissions are from brake and tyre wear.
6 Figure 3-1: Estimated annual PM10 emissions for 2016 by emission type .
The 2016 inventory estimates that petrol cars account for 20 per cent of PM10 emissions (Figure 3-2) but represent almost 67 per cent of annual VKT. Diesel light commercial vehicles (LCV) account for 36 per cent of PM10 emissions and heavy commercial vehicles (HCV) > 3.5t account for 26%, despite representing 14 per cent and seven per cent of VKT, respectively.
6 Hybrid and electric vehicle emissions are not shown here as the contribution to 2016 emissions is less than 1%.
Auckland air emissions inventory 2016 – transport (revised) 13
Figure 3-2: Estimated annual PM10 emissions for 2016 by vehicle type. NOx The 2016 inventory estimates total nitrogen oxides (NOx) emissions from motor vehicles to be approximately 10,250t/yr for 2016. This accounts for 66 per cent of emissions from all transport sources in 2016 (excluding shipping). The 2016 inventory estimates that petrol cars emit 34 per cent of NOx although they represent 67 per cent of VKT (Figure 3-3). In contrast, HCVs > 7.5t account for 33 per cent of NOx emissions but represent only six per cent of VKT.
Figure 3-3: Estimated annual NOx emissions for 2016 by vehicle type.
3.2.1 Projections and other years
Auckland air emissions inventory 2016 – transport (revised) 14 This section presents emission projections for motor vehicles. The projections show that, despite a predicted increase in VKT, there is generally a predicted decrease in vehicle emissions over time. This is due to improvements in new vehicle technology. It is expected that emissions from the fleet will gradually reduce as new (lower emission) vehicles are introduced into the fleet and older (higher emission) vehicles are retired from the fleet. Further information about individual vehicle emissions and how they are predicted to change in the future is available in VEPM technical reports (NZTA, 2017). It is important to note the limitations of these projections. In particular:
The projections are based on projections from the ART model and VEPM. Each of these models is based on current knowledge and expectations, however they are based on assumptions and have significant uncertainty.
Continuous monitoring, validation and review of progress against targets is critical. The importance of this has been illustrated in Europe where predicted
reductions in ambient NO2 concentrations have not been measured in real life. Researchers have found that this difference between models and reality is due to the growing gap between legal vehicle emission limits and vehicle emissions in the real world (see for example ICCT, 2017).
PM10
PM10 emissions from motor vehicles are predicted to reduce to 306t/yr by 2040, despite a predicted 12 per cent increase in VKT under business as usual conditions between 2016 and 2040 (Figure 3-4). There is little predicted change in the overall emissions from petrol vehicles between 2016 and 2040, but emissions from diesel vehicles are predicted to decrease substantially.
Estimated PM10 emissions are compared in Figure 3-5 with the Auckland Plan target of reducing PM10 emissions in the region (based on 2006 levels) 50 per cent by 2016 and 70 per cent by 2040. This shows that, under business as usual conditions, PM10 emissions are estimated to reduce by 31 per cent between 2006 and 2016 (from 937t/yr to 647t/yr) but does not achieve the 50 per cent reduction required by the Auckland Plan by 2016. This is a 38 per cent shortfall on the Auckland Plan’s 2016 target of 469t/yr. Emissions for 2040 are projected to reduce by 67 per cent (to 306t/yr). This will be a nine per cent shortfall on the 2040 target of 281t/yr.
Auckland air emissions inventory 2016 – transport (revised) 15
Figure 3-4: PM10 emission estimates from 2001 to 2016 and emission projections to 2040 by vehicle type and total VKT.
1,200
1,000
800 (t/yr)
600 emissions 10 400 PM
200
0 2001 2006 2011 2016 2021 2026 2031 2036 2040 PM10 emissions Reduction target 2016 Reduction target 2040
Figure 3-5: Estimated and projected PM10 emissions compared against Auckland Plan targets.
Auckland air emissions inventory 2016 – transport (revised) 16
NOx NOx emissions are projected to reduce to approximately 5230t/yr by 2040 due to improvements in vehicle technology (Figure 3-6).
Figure 3-6: NOx emission estimates from 2001 to 2016 and emission projections to 2040 by vehicle type and total VKT.
Figure 3-7 shows the annual estimated and projected NOx and NO2 emissions between 2001 and 2040. This shows that, although NOx emissions reduced by 34 per cent between 2006 and 2016, estimated emissions of NO2 increased by one per cent over the same period. Looking forward to 2040, NOx emissions are projected to reduce by 66 per cent compared with 2006 emissions and NO2 emissions are projected to reduce by 36 per cent compared with 2006.
Auckland air emissions inventory 2016 – transport (revised) 17
Figure 3-7: Comparison between estimated and projected NOx and NO2 emissions between 2001-2040.
3.2.2 Alternative scenario
The business as usual (BAU) projection assumed that current trends will continue. An alternative scenario projection referred to as an indicative package was developed for the Auckland Transport Alignment Project (ATAP)7. Figure 3-8 shows the projected PM10 emissions from motor vehicles under this scenario along with projected VKT. The results show that there is little difference in PM10 estimates between business as usual and scenario projections.
7 The indicative package was a scenario from the Auckland Transport Alignment Project as at December 2016. This indicative package was developed to inform upcoming funding decisions and development of Auckland’s Regional Land Transport Plan. The scenario included a mixture of committed and uncommitted investment (as at December 2016). The scenario represents a possible transport future that has not yet been finalised. Full details of the scenario are available on the Ministry of Transport’s website (MoT, 2018)
Auckland air emissions inventory 2016 – transport (revised) 18
Figure 3-8: Comparison between BAU and indicative package PM10 emissions projections and VKT.
3.2.3 Sensitivity
The sensitivity of the motor vehicle emissions inventory to key input factors was explored in previous inventories, and the approach has not changed for this inventory. Some key conclusions from the 2011 inventory (Auckland Council, 2014c) were:
Diesel vehicles emit disproportionately higher PM10 emissions per kilometre compared with petrol vehicles. Regional emissions are, therefore, sensitive to the proportion of diesel vehicles in the total vehicle kilometres travelled. Given that Auckland’s topography is relatively undulating, the gradient of a road can heavily influence vehicle speed and the speed-based emission factor, which could have a significant effect on regional emissions and fuel consumption estimates.
Auckland air emissions inventory 2016 – transport (revised) 19 The NZ Transport Agency have calculated gradient for each road in Auckland for a national emissions mapping project.8 These data were unavailable at the time of writing this report but could be used in the future to estimate gradient effects more adequately.
3.3 Uncertainty
There are many variables that contribute to uncertainty in the vehicle emissions inventory, including:
fleet weighted emission factors: o The emission factors themselves o Allocation of vehicles to different technology classes and sizes (engine capacity or weight classes) o Contribution of cold starts load factor (heavy vehicles) effect of gradient speed total VKT. This assessment considers uncertainty in fuel consumption and fleet average emission factors to provide an overall first order assessment of uncertainty. Remote sensing of vehicle exhaust emissions provides an indication of real-world emission factors. These ‘real-world’ factors include the influence of cold starts, as well as allocation of vehicles to different technology classes. Comparing emission factors assumed in the inventory with emission factors derived from remote sensing results provides an indication of the overall uncertainty associated with fleet weighted emission factors. Fuel sales figures provide a real-world check of inventory predictions. Fuel consumption predictions from VEPM are sensitive to VKT, speed, and gradient (Auckland Council, 2014b). This means that comparison of predicted fuel consumption with real-world fuel sales figures provides some indication of the overall uncertainty associated with these variables.
8 Presentation by G Haldane (NZ Transport Agency) at the Clean Air Society of Australia and New Zealand’s Transport Special Interest Group workshop Vehicle emission mapping tool. 12 December 2017.
Auckland air emissions inventory 2016 – transport (revised) 20 3.3.1 Exhaust emission factor uncertainty
The uncertainty of motor vehicle emission factors varies depending on the pollutant, vehicle class, vehicle technology, and speed. Quantitative uncertainties for fleet weighted emission factors are not readily available. In New Zealand, the authors of VEPM have not attempted a quantitative estimation of overall uncertainty in VEPM emission factors. However, they provide an expert judgement as follows (EFRU, 2008): It is believed that the uncertainty will vary in the range 20 to 100% and will vary according to the make-up of the fleet being investigated. It is anticipated that if the fleet consisted entirely of European vehicles, uncertainty would be close to 20%. Conversely, if the fleet was predominantly of Japanese origin with a high proportion of HDV’s, the uncertainty could be as high as 100%. In this assessment, the make-up of the fleet was based on national fleet statistics, which show that approximately 45 per cent of light duty vehicles and 35 per cent of heavy duty vehicles are used imports. The proportion of heavy duty vehicles in the fleet was based on Auckland Transport data and was approximately 5.5 per cent in 2016.9 In the context of the uncertainty in VEPM (as stated above), the fleet is approximately half Japanese origin with a moderate proportion of HCVs. This means that the uncertainty in emission can be assumed to be approximately half way between 20 per cent and 100 per cent (i.e. around 60%). An indication of uncertainty is also available from remote sensing monitoring results in New Zealand.
3.3.1.1 Remote sensing
Regular monitoring with the remote sensing device (RSD) has provided a direct measure of real-world emission vehicle emission trends in New Zealand (Golder, 2014). RSD monitoring was undertaken in 2003, 2005, 2009, 2011 and 2015 at seven sites across the Auckland region (Golder, 2014). Over the course of these monitoring campaigns, exhaust concentrations from more than 100,000 light vehicles were measured. RSD measures the concentration of contaminants in the exhaust stream including CO (%), HC (ppm) and NO (ppm). UV smoke index is used to estimate particulate emissions. The concentration results can be converted to emission factors (in g/km) with some significant assumptions including:
9 Personal comms. T Ballance, Auckland Transport, 7 July 2017.
Auckland air emissions inventory 2016 – transport (revised) 21 The conversion of concentration results to g/km emission factors relies on estimated fuel consumption rates. The RSD measures instantaneous emission concentration at a particular point on the road, generally on motorway on- or off-ramps, arterial roads, or one way streets. Although there are many measurements, they may not be representative of average emissions over a full drive cycle. Measurements are less accurate than laboratory measurements.
The RSD measures NO. To estimate NOX, it is necessary to make
assumptions about the amount of NO2 in the exhaust. UV smoke index only provides an indication of likely particulate concentration. The results of the 2011 remote sensing campaign were used to derive light duty vehicle emission factors for CO, NOx, HC and PM to compare with VEPM (Golder, 2014). Subject to the limitations and assumptions in the method, the report concludes that there is reasonable agreement between VEPM and RSD-derived emission factors for most combinations of vehicle type and pollutant (Table 3-4: Comparison of VEPM and RSD-derived emissions factors).
Table 3-4: Comparison of VEPM and RSD-derived emissions factors
Petrol car Petrol LCV Diesel car Diesel LCV Pollutant Emission factor (g/km) CO RSD 5.19 8.75 0.37 0.33 VEPM 8.71 13.86 0.54 0.78 % difference vs VEPM -40% -37% -31% -58% NOx RSD 0.68 1.37 0.52 0.67 VEPM 0.69 0.96 0.85 1.35 % difference vs VEPM 1% 43% -39% -50% Hydrocarbons RSD 0.69 1.23 0.35 0.37 VEPM 0.48 1.37 0.1 0.08 % difference vs VEPM 44% -10% 250% 363% PM RSD 0.041 0.084 0.138 0.115 VEPM 0.005 0.004 0.264 0.174 % difference vs VEPM 720% 2000% 48% -34%
(Source: Golder, 2014). For pollutants with very low relative emission factors (hydrocarbons from diesel vehicles and particulate from petrol vehicles) the difference between VEPM and RSD-derived factors was very high. The errors and assumptions in deriving emission factors from RSD results are likely to be much higher at these very low
Auckland air emissions inventory 2016 – transport (revised) 22 concentrations, so these results were not considered to reasonably represent the likely margin of error. For other pollutants, the percentage difference between VEPM and RSD emission factors is generally in the range of 30 to 60 per cent (Table 3-4: Comparison of VEPM and RSD-derived emissions factors).
3.3.1.2 Assumed uncertainty in exhaust emission factors
For this analysis, the uncertainty for light duty vehicles was assumed to be equal to the difference between VEPM and RSD-derived emissions factors (from Table 3-4: Comparison of VEPM and RSD-derived emissions factors), with a minimum of 20 per cent and a maximum of 100 per cent (based on the uncertainty in emission factors estimated by VEPM authors (EFRU, 2008) as discussed in Section 3.3.1). For heavy duty vehicles, there is very little data available in New Zealand, so the uncertainty was assumed to be 100 per cent based on the upper estimate of uncertainty in emission factors estimated by VEPM authors (EFRU, 2008) as discussed in Section 3.3.1. The uncertainty in emission factors is summarised in Table 3-5.
Table 3-5: Assumed uncertainty in exhaust emission factors
Petrol car Petrol LCV Diesel car Diesel LCV Heavy Pollutant Uncertainty CO 40% 37% 31% 58% 100% NOx 20% 43% 39% 50% 100% VOC 44% 20% 100% 100% 100%
PM10 100% 100% 48% 34% 100%
3.3.2 Brake and tyre wear emission factor uncertainty
Brake and tyre wear emission factors in VEPM are based on the EMEP/EEA guidebook. The 95 percentile confidence intervals are provided in the guidebook. For this assessment, uncertainty parameters for brake and tyre wear combined were calculated based on the EMEP/EEA guidebook (Table 3-6).
Table 3-6: Uncertainty in brake and tyre wear particulate emission factors
Vehicle class Uncertainty Light duty 44%
Light commercial 38%
Heavy duty 38%
(Source: EEA, 2016).
Auckland air emissions inventory 2016 – transport (revised) 23 3.3.3 Activity data uncertainty
3.3.3.1 Comparison with fuel sales data
Comparison of predicted fuel consumption with regional fuel sales data (Table 3-7) provides an indication of overall uncertainty in the activity data, including VKT, speed gradient, and load. Fuel sales data for land transport were provided by Auckland Transport. In this assessment, it was assumed that fuel sales should match on-road motor vehicle fuel consumption. This is consistent with the assumptions of the Auckland Greenhouse Gas Emissions Inventory (Xie, 2016).
Table 3-7: Comparison of fuel sales with fuel consumption predicted by inventory for 2016
Fuel sales 2016 inventory Difference Fuel Auckland estimate Million litres
Petrol 1,096 868 21%
Diesel 616 477 23%
Total 1,712 1,338 22%
The results of this comparison are consistent with the previous motor vehicle emissions inventory (Auckland Council, 2014c) which found that the inventory consistently underestimated total fuel consumption compared with fuel sales by around 20 per cent for 2001, 2006 and 2011.
3.3.3.2 Comparison with real-world fuel consumption figures for light duty vehicles
Ministry of Transport have published real-world fuel consumption factors, which provide another opportunity to compare the inventory with reality. Real-world fuel consumption factors were developed based on a large dataset of on-road fuel use of corporate fleets comprising more than 9000 vehicles (Wang et al., 2015). The fleet- weighted travel average fuel efficiency of the analysed light petrol fleet was 9.2l/100km and the light duty diesel fleet was 10.1l/100km. These real-world factors from the Ministry of Transport (MoT) are approximately four per cent lower for light duty petrol vehicles and approximately 13 per cent higher for heavy duty diesel vehicles compared with the average predicted fuel consumption of light duty vehicles in this 2016 Auckland inventory Table 3-8).
Auckland air emissions inventory 2016 – transport (revised) 24
Table 3-8: Comparison of light duty vehicle fuel consumption from the 2016 inventory with MoT real-world fuel consumption factors
2016 MoT real- Fuel inventory world fuel estimate consumption litres/100km Petrol 9.6 9.2 Diesel 8.9 10.1
3.3.3.3 Comparison with real-world fuel consumption figures for heavy duty vehicles
Real-world fuel consumption factors for heavy duty vehicles have been developed by MoT based on analysis of fleet fuel consumption and travel data (Table 3-9). These real-world factors result in a fleet-weighted fuel consumption of 38 l/100km. This is approximately 35 per cent higher than the fleet-weighted fuel consumption estimated from the 2016 inventory.
Table 3-9: Comparison of MoT real-world diesel consumption factors for heavy duty vehicles with the 2016 inventory
Proportion of Fleet 2016 Real-world Vehicle heavy duty fleet weighted real- inventory fleet fuel weight in Auckland world fuel weighted fuel consumption inventory consumption consumption litres/100km % litres/100km <5 t 15.9 10
5- <7.5 t 16 10
7.5 - <10 t 22.2 6
10 - <12 t 24.9 6
12 - <15 t 30.8 3 38 25
15 - <20 t 33.3 5
20 - <25 t 44.2 15
25 - <30 t 48.8 19
>=30 t 50.6 26
This comparison of fuel consumption estimated from the 2016 inventory with real- world fuel consumption factors and fuel sales data suggests that further work is
Auckland air emissions inventory 2016 – transport (revised) 25 required to better understand real-world fuel consumption in Auckland and to improve activity data or estimates from VEPM so that inventory estimates can be improved. For this assessment it was estimated that activity data has an uncertainty of ±21% and ±23% for petrol and diesel vehicles respectively based on the discrepancy between predicted fuel consumption and actual regional fuel sales data.
3.3.4 Overall assessment of uncertainty in motor vehicle emissions
Overall, the uncertainty associated with particulate emissions from motor vehicles was estimated according to Equation 1 and Equation 2 as 31 per cent (see Section 9).
Auckland air emissions inventory 2016 – transport (revised) 26 4.0 Aviation
This section provides a comprehensive assessment of emissions to air from aircraft at Auckland International Airport Limited. It should be noted that because the methodology, emission factors, and activity data for the 2016 inventory were different to previous inventories, the results are not directly comparable. However, emissions have been estimated in this inventory for previous years to provide for trend analysis.
4.1 Methodology
For the 2016 inventory, the Tier 2 method from the EMEP/EEA guidebook was undertaken to assess aircraft emissions from the Auckland International Airport. An aircraft movement includes several phases of a flight including taxi out, take-off, climb, cruise, descent, approach, landing and taxi-in (Figure 4-1).
(Source: EEA, 2016). Figure 4-1: Typical phases of flight.
For the purposes of this inventory, an aircraft movement is a phase that takes place below a height of 915 metres (3000 feet)10 and includes taxi-out, take-off, climb-out, approach, landing and taxi-in. It is referred to through the rest of this report as the
10 Emissions from aircraft phases above 915 metres are not included in this inventory but are included in greenhouse gas emissions inventories.
Auckland air emissions inventory 2016 – transport (revised) 27 landing and take-off (LTO) cycle of an aircraft. Emissions from cruise, climb, and descent phases (CCD) were not quantified for this inventory. The Tier 2 method is used when information on the landing and take-off (LTO) phases by aircraft type is available. Emissions are then calculated as follows:
E LTO EF Equation 5
Where:
Epollutant is emission of pollutant for each of the LTO phases.
LTOaircraft type is the number of LTO phases by each aircraft type.
EFaircraft type is the emission factor of pollutant for the LTO phase by aircraft type.
4.1.1 Activity data
The Tier 2 method requires data on the number of aircraft movements by aircraft type. A schedule of departures and arrivals at Auckland International Airport were extracted for a week in June 2017 to collate data on the number of LTO movements by aircraft type. There are 33 different types of aircraft operating at Auckland International Airport (as listed in Table 4-1).
4.1.1.1 Aircraft movements for previous years
Aircraft movements were sourced for 2001, 2006 and 2011 for Auckland International Airport to backcast emissions from aviation. Between 2001 and 2006 there was a gradual increase in the number of passenger and aircraft movements through Auckland and was reflected in changes to the fleet made by airlines (such as Air New Zealand) during this period.
4.1.1.2 Projections
Auckland International Airport has recently experienced growth in the number of passengers travelling in and out of Auckland. However, while passenger movements have significantly increased, the number of flights has not increased at the same rate (AIAL, 2014). Technological changes in the aviation industry will mean that, in the future, commercial aircraft will be more efficient, larger and have the capacity to carry more passengers (Figure 4-2).
Auckland air emissions inventory 2016 – transport (revised) 28
(Source: AIAL, 2014). Figure 4-2: The changing nature of aircraft since 1960.
Auckland International Airport forecasts the number of flights to almost double by 2044 to keep up with passenger demand (AIAL, 2014). To cope with this growth and the larger aircraft, a second runway at the airport has been announced with the expectation that it will be operational by 2028 (AIAL, 2017). For the purposes of this study, aircraft movements for 2040 were assumed to be the same as aircraft movements projected for 2044. Aircraft movements were interpolated for the years 2026 and 2036 as there were no data available.
4.1.2 Emission factors
Emission factors were obtained from the EMEP/EEA guidebook (EEA, 2016) and associated Master emissions calculator 2016 workbook. The workbook has LTO fuel consumption and emission factors for various types of aircraft, the type of model most commonly associated with that type of aircraft and the most frequently used engine type (Table 4-1). The EMEP/EEA guidebook does not list emission factors for all aircraft types and models, so where data for a particular aircraft was not available, the next best model representing the aircraft type was chosen. The emission factors are default International Civil Aviation Organisation’s (ICAO) values based on their standard landing, take off, and taxi times. Every airport is different so it is likely that these will differ significantly from the times associated with each of these phases at Auckland International Airport. An emission factor per LTO was calculated for each pollutant based on 2016 estimates to calculate emissions for other inventory years.
Auckland air emissions inventory 2016 – transport (revised) 29 Table 4-1: Aircraft specific LTO emission factors in kg/LTO
Aircraft type Manufacturer 3 Engine Engine No. Fuel CO2 NOx SO2 CO HC PM TOTAL Model 4 ICAO1 IATA2 and aircraft type ID Engines burn (kg) (kg) (kg) (kg) (kg) (kg) (kg) A320 320 Airbus A320‐100/200 A320 233 Jet 3CM026 2 816.17 2570.93 11.28 0.69 8.25 1.64 0.07 A330 330 Airbus A330 all models A330 201 Jet 14RR071 2 2168.08 6829.44 35.32 1.82 21.19 2.10 0.16 A332 332 Airbus A330‐200 A330 201 Jet 14RR071 2 2168.08 6829.44 35.32 1.82 21.19 2.10 0.16 A333 333 Airbus A330‐300 A330 322 Jet 14RR071 2 2168.08 6829.44 35.32 1.82 21.19 2.10 0.16 A343 343 Airbus A340‐300 A340 313 Jet 2CM015 2 2019.89 6362.65 34.81 1.70 25.23 3.90 0.50 A359 359 Airbus A350‐900 A350 941 Jet 14RR075 2 2137.98 6734.64 40.49 1.80 19.55 0.85 0.16 A388 388 Airbus A380‐800 A380 842 Jet 8RR046 4 4142.40 13048.56 67.26 3.48 29.62 0.38 0.25 Aerospatiale/Alenia AT72 AT7 Turboprop Turboprop 2 ATR 72 ATR72 212 F 242.76 764.71 2.34 0.20 1.54 0.00 0.00 Aerospatiale/Alenia AT75 ATR Turboprop Turboprop 2 ATR 72‐500 ATR72 212 F 242.76 764.71 2.34 0.20 1.54 0.00 0.00 Aerospatiale/Alenia AT76 ATR Turboprop Turboprop 2 ATR 72‐600 ATR72 212 F 242.76 764.71 2.34 0.20 1.54 0.00 0.00 B737 737 Boeing 737 B737 75R Jet 3CM032 2 824.65 2597.65 10.30 0.69 8.00 0.86 0.07 B738 738 Boeing 737‐800 B737 800 Jet 8CM051 2 881.10 2775.47 12.30 0.74 7.07 0.72 0.07 B738 73H Boeing 737‐800 (winglets) B737 800 Jet 8CM051 2 881.10 2775.47 12.30 0.74 7.07 0.72 0.07 B744 744 Boeing 747‐400 B747 400 Jet 2GE045 4 3319.68 10456.98 44.45 2.79 25.27 2.05 0.21 B744 74F Boeing 747 Freighter B747 400 Jet 2GE045 4 3319.68 10456.98 44.45 2.79 25.27 2.05 0.21 n/a 74Y Boeing 747‐400 Freighter B747 400 Jet 2GE045 4 3319.68 10456.98 44.45 2.79 25.27 2.05 0.21 B752 75F Boeing 757 Freighter B757 200 Jet 5RR038 2 1362.60 4292.19 14.98 1.14 12.25 0.17 0.16 n/a 76F Boeing 767 Freighter B767 200 Jet 1GE012 2 1462.66 4607.37 23.76 1.23 14.80 3.32 0.16 B763 763 Boeing 767‐300 B767 300 Jet 12PW101 2 1729.93 5449.29 26.67 1.45 29.65 7.56 0.16
B772 772 Boeing 777‐200 B777 200 Jet 8GE100 2 2406.41 7580.19 61.24 2.02 12.31 0.44 0.16
Auckland air emissions inventory 2016 – transport (revised) 30 Table 4-1: Aircraft specific LTO emission factors in kg/LTO (cont.)
Aircraft type Manufacturer 3 Engine Engine No. Fuel CO2 NOx SO2 CO HC PM TOTAL Model 4 ICAO1 IATA2 and aircraft type ID Engines burn (kg) (kg) (kg) (kg) (kg) (kg) (kg) n/a 777 Boeing 777 B777 300ER Jet 7GE099 2 3090.84 9736.15 69.79 2.60 47.54 5.10 0.21
B77L 77L Boeing 777‐200LR B777 300ER Jet 7GE099 2 3090.84 9736.15 69.79 2.60 47.54 5.10 0.21
B77W 77W B777 300ER B777 300ER Jet 7GE099 2 3090.84 9736.15 69.79 2.60 47.54 5.10 0.21
B788 788 Boeing 787‐8 B787 800 Jet 11GE136 2 1592.36 5015.95 17.15 1.34 14.51 0.53 0.09
B789 789 Boeing 787‐9 B787 900 Jet 12RR055 2 1726.66 5438.97 34.52 1.45 6.80 0.04 0.10
CVLT CV5 Convair CV‐580 L188PF Turboprop Turboprop 4 856.47 2697.87 0.88 0.72 0.00 0.08 0.00
De Havilland Canada DH8C DH3 DHC8 314Q Turboprop Turboprop 2 242.08 762.55 2.33 0.20 1.54 0.00 0.00 DHC‐8‐300 Dash 8 / 8Q
MD11 M11 McDonnell Douglas MD11 MD11ER F Jet 2GE049 2 2627.91 8277.92 38.17 2.21 18.28 1.43 0.17
SF34 SF3 Saab SF340A/B SF340A Turboprop Turboprop 2 145.06 456.93 0.89 0.12 0.95 0.48 0.00
Fairchild (Swearingen) SA 226TC n/a SWM Turboprop Turboprop 2 86.48 272.42 0.62 0.07 1.23 0.11 0.00 SA26 / SA226 METRO II (Source: EEA, 2016).
Notes 1 International Civil Aviation Organisation (ICAO) codes are used for "official" purposes such as Air Traffic Control. 2 International Air Transport Association (IATA) codes are mainly used for ticketing and public reference. 3 Type of model most commonly associated with this type of aircraft and assumed aircraft type for these calculations. 4 The most common engine ID in 2015 used for modelling this aircraft type.
Auckland air emissions inventory 2016 – transport (revised) 31 4.1.2.1 Sulphur in jet fuel
Jet fuel in New Zealand generally has a sulphur level between 100 to 500ppm however, under the international Jet A-1 specification; the sulphur content can be up to 3000ppm (MBIE, 2010). Given this range in values, default emission factors11 for
SO2 from the EMEP/EEA guidebook were used.
4.1.3 Limitations and exclusions
Other airports Auckland International Airport is the largest airport in Auckland as well as New Zealand. There are three other airports in the Auckland region (Ardmore Airport, North Shore Aerodrome, and the military airbase at Whenuapai) which service mainly smaller planes and military aircraft. These smaller airports were not included, as detailed data were not available at the time of writing this report. Previous inventories estimated that almost 97 per cent of aircraft movements are at Auckland International Airport while Ardmore airport accounted for 2.5 per cent of movements, and Whenuapai airbase and North Shore Aerodrome accounted for <1 % each (Auckland Council, 2014a). Aviation gasoline Emissions from aviation mainly come from the combustion of fuels such as jet fuel or aviation gasoline (AvGas). Aviation gasoline is only used by small aircraft and helicopters fitted with piston engines and were not included in the 2016 inventory as the details for these types of aircraft (at any of the four airports) were not available.
4.2 Results
Table 4-2 shows the results for aircraft emissions for 2016. PM10 emissions from aircraft at Auckland International Airport were estimated as 10t/yr for 2016 and are only one per cent of total regional PM10 emissions from transport sources presented in this report. NOx emissions were estimated at approximately 2595t/yr, which account for 17 per cent of regional transport emissions. A total of 121t/yr of SO2 emissions were estimated from aircraft which accounted for 62 per cent of regional transport emissions. Given the location of the airport, all aircraft emissions were assumed to occur entirely within the Auckland Urban Airshed.
11 The default assumes 840ppm sulphur in jet fuel and is calculated based on fuel consumption.
Auckland air emissions inventory 2016 – transport (revised) 32 Table 4-2: Estimated aircraft emissions from 2001 to 2040
2001 2006 2011 2016 2026 2036 2040
Annual movements 147,868 160,899 156,764 161,460 196,653 231,846 260,000
Annual emissions (t/yr) CO 1,175 1,278 1,245 1,283 1,562 1,842 2,065
CO2 416,958 453,703 442,043 455,285 554,522 653,758 733,148 NOx 2,376 2,586 2,519 2,595 3,160 3,726 4,178
SO2 111 121 118 121 148 174 196 HC 140 152 148 153 186 220 246
PM10 9 10 9 10 12 14 16
PM2.5 9 10 9 10 12 14 16
4.2.1 Projections and other years
Table 4-2 also shows estimated emissions from 2001 to 2011, and projections for 2026 to 2040. A detailed inventory was not developed for future years as there was no information available. Projections were therefore based on projected aircraft movements assuming no change in emissions per movement. Projections were calculated for 2040 and interpolated for other years as shown in Figure 4-3 for NOx. Estimates indicate that emissions will increase given the increase in aircraft movements; however, emissions may reduce with improvements in aircraft technology, energy efficiency, and emissions control.
Auckland air emissions inventory 2016 – transport (revised) 33
Figure 4-3: NOx emissions estimates and aircraft movements from 2001 to 2016 and projections to 2040.
4.3 Uncertainty
4.3.1 Uncertainty of emission factors
The EMEP/EEA guidebook states that for a Tier 1 assessment, based on default fleet averaged emission factors, the uncertainty in emission factors is estimated at 20 to 30%. This assessment was equivalent to a Tier 2 assessment, which used local data for calculation of fleet weighted averages. Estimated uncertainty for this type of Tier 2 assessment is not provided in the EMEP/EEA guidebook, so for this analysis the lowest suggested uncertainty for a Tier 1 assessment (20%) was assumed.
4.3.2 Uncertainty in activity data
Activity data was obtained from the Auckland International Airport website of flight arrivals and departures each day for a week in June 2017. This was a snapshot in time and while it is indicative of the number of flight movements in a week, it does not consider the increased services during long weekends, school holidays or the peak holiday season. The annual movements estimated based on the June 2017 week was 161,460, however for 2016, the number of aircraft movements are recorded as
Auckland air emissions inventory 2016 – transport (revised) 34 165,67512 (Airways Ltd, 2017). Based on this difference, the uncertainty in activity data for Auckland International Airport was assumed to be 3%. As mentioned earlier, other airports in the region were not included in the 2016 inventory due to activity data and aircraft details not being available at the time of writing this report. As a result, emissions from aircraft in the region are likely be somewhat higher than this estimate.
4.3.3 Overall uncertainty
Overall, the uncertainty associated with particulate emissions from aviation was estimated according to Equation 2 as 20 per cent (see Section 9).
12 This includes international flights under international flight rules (IFR), and domestic flights under IFR and visible flight rules (VFR). The flight schedule from Auckland International Airport only includes international and domestic IFR flights.
Auckland air emissions inventory 2016 – transport (revised) 35 5.0 Rail
Emissions from railways occur from the combustion of fuels in engines and from non-exhaust particulates from brake and wheel wear on the tracks. The 2016 inventory uses fuel consumption as the basis for estimating emissions. It should be noted that because the methodology, emission factors, and activity data were different to previous inventories, the results are not directly comparable. Emissions have therefore been estimated for previous years to provide for trend analysis.
5.1 Methodology
For this inventory, the Tier 1 methodology from the EMEP/EEA guidebook was used to estimate emissions from rail. The Tier 1 method is a fuel-based methodology, calculated as per the following equation (EEA, 2016):
E FC EF , Equation 6
Where:
Ei = emissions of pollutant i for the period concerned in the inventory (kg or g),
FCm = fuel consumption of fuel type m for the period and area considered (tonnes),
EFi = is the emission factor of pollutant for each unit of fuel type m used (kg/t), m = fuel type (diesel, gas, oil).
5.1.1 Activity data
Rail is mostly used in Auckland for the mass transit of daily commuters within the region (managed by Auckland Transport) or for moving freight within or to and from Auckland (managed by KiwiRail).13
13 The Northern Explorer long distance passenger train service from Auckland to Wellington was not included in this inventory.
Auckland air emissions inventory 2016 – transport (revised) 36 5.1.1.1 Passenger rail
Many changes have taken place to the passenger rail network in Auckland since the opening of the Britomart Transport Centre in 2003 including:
Double tracking of all four main commuter lines, Rebuilding and reconfiguring the Newmarket Train Station, Constructing the new Manukau branch line from Wiri to Manukau City, Reopening the Onehunga branch line, Increased rail services, Electrification of the network and introducing electric commuter trains in 2015. The 2016 rail fleet in Auckland consisted of two types of railcar14 locomotives:
New Zealand Auckland Metro (AM class) electric multiple units (EMUs) operating on all suburban rail network lines; and ADL class diesel multiple units (DMUs) operating on the Papakura to Pukekohe line. Note: Electric trains are powered by electricity generated at power stations, which are indirect emissions and were therefore not included in this inventory. Fuel consumption data specifically for passenger rail was obtained from Auckland Transport (Table 5-1). This clearly shows the impact of electric trains on fuel consumption since their introduction in 2015. In 2016, the only consumption of diesel for passenger trains was from the diesel-electric services operating between Papakura and Pukekohe.
Table 5-1: Fuel consumption for passenger rail 2009-2016 (Source: Auckland Transport)
2010 2011 2012 2013 2014 2015 2016
Diesel (t/yr) 6,976 7,444 8,445 8,241 8,476 6,221 430
5.1.1.2 Previous years and projections
Table 5-1 above shows fuel consumption data for 2010 to 2016. However, fuel consumption for passenger rail was not available for 2001 and 2006 at the time of writing this report. To back-calculate fuel consumption (for trend analysis), it was assumed that annual fuel consumption for passenger rail was proportional to the
14 Railway locomotives consisting of a coach powered by its own power unit.
Auckland air emissions inventory 2016 – transport (revised) 37 number of journeys to work by rail. Fuel consumption for 2001 and 2006 was estimated based on 2013 fuel consumption (Table 5-1) and journey to work data for 2001, 2006 and 2013 as shown in Table 5-2.
Table 5-2: Means of travel to work in Auckland (train) 2001, 2006 and 2013
2001 2006 2013
Travel to work by train* 2,418 5,655 9,462 2,106 4,925 8,241 Diesel (t/yr) (estimated) (estimated) (actual) *Main means of travel to work, for the employed census usually resident population count aged 15 years and over, 2001, 2006, and 2013 Censuses (Source: Statistics NZ, 2017).
Future expansion of the Auckland rail network includes projects such as the City Rail Link, which will also be electrified as part of Auckland’s railway electrification and are unlikely to result in exhaust emissions. Similarly, the Papakura to Pukekohe line is also expected to be electrified by 2019. Exhaust emissions from passenger rail were therefore assumed to be zero for future inventory years.
5.1.1.3 Freight
KiwiRail is responsible for rail operations and track maintenance in New Zealand. Freight is KiwiRail’s largest business unit, moving around 18 million tonnes of freight nationally for the financial year ending in 2016 (KiwiRail, 2016). In Auckland, KiwiRail covers approximately 172km of track,15 extending from Wellsford in the north to Pukekohe in the south. In the financial year ending 2016, the average freight train kilometres covered in Auckland totalled 465,360 km.16 KiwiRail currently operates New Zealand DL class (diesel-electric) locomotives, which were introduced in 2010. Fuel consumption data for freight services were obtained from KiwiRail (Table 5-3). Diesel consumption for 2016 was calculated based on the total gross tonne
15 This does not allow for the double tracking of the Auckland network (personal comms. J James, KiwiRail, 24 May 2017). 16 Personal comms. J James, KiwiRail, 24 May 2017.
Auckland air emissions inventory 2016 – transport (revised) 38 kilometres (GTKs) over the Auckland corridor multiplied by a fuel burn rate (in litres per GTK).17 Fuel consumption was also calculated for the years 2006 and 2011 based on total GTK and fuel burn rate for each respective year (Table 5-3). Data were not available for 2001 and therefore were back-calculated based on the assumption that the period between 2001-2006 experienced the same trend as 2006-2011.
Table 5-3: Fuel consumption for freight 2006-2040
2001 2006 2011 2016 2021 2026 2031 2036 2040
Diesel (t/yr) 2,007* 2,058 2,108 2,170
% growth 10% 14% 11%
Diesel (t/yr) 2,387 2,555* 2,722 2,871* 3,021 (Source: Personal comms. J James, KiwiRail, 24 May 2017). * Interpolated values.
A commercial review of KiwiRail was completed in 2014, looking at future options for the business out to 2045. As part of this, GTKs per annum were calculated by the three corridors that 'touch' Auckland and growth estimated for the Auckland corridor (the three corridors are North Auckland, Auckland Christchurch and Auckland Bay of Plenty). Table 5-3 shows the projected growth expected on the Auckland corridor for 2021, 2031 and 204018 financial years. Projections were interpolated for 2026 and 2036 for reporting purposes.
5.1.2 Emission factors
While a Tier 1 methodology is used to calculate emissions from rail in this inventory,
Tier 2 emission factors from the EMEP/EEA guidebook were used (except for SO2), as specific fuel consumption data were available for individual locomotive types (i.e. railcar and line haul locomotives). Table 5-4 presents the emission factors used.
17 Fuel burn rate is the average for the national rail network and is not specific to the Auckland corridor. 18 Fuel consumption for the 2041 financial year assumed for 2040.
Auckland air emissions inventory 2016 – transport (revised) 39 5.1.2.1 Non-exhaust particulate
While brake and wheel wear can be a source of particulate from trains, these were not included in this inventory because emission factors were not available in the European (EEA, 2016), United States (US EPA, 2009), or Australian (Environment Australia, 1999) inventory guidance.
Table 5-4: Emission factors and confidence intervals for rail
EF 95% EF 95% Pollutant (kg/t fuel) Confidence Interval (kg/t fuel) Confidence Interval Line-haul Lower Upper Railcar Lower Upper CO 18.0 5.0 21.0 10.8 6.0 20.0
CO2 3140 3120 3160 3140 3120 3160 NOx 63.0 29.0 93.0 39.9 22.0 78.0
SO2* 0.02 n/a 0.02 n/a TSP 1.80 0.32 6.00 1.50 0.24 9.00
PM10 1.20 0.45 3.00 1.10 0.28 4.00
PM2.5 1.10 0.42 3.00 1.00 0.26 3.00 VOC 4.80 2.00 9.00 4.70 2.00 8.00 (Source: EEA, 2016). * Calculated based on the sulphur content in diesel (0.02 g/kg).
5.2 Results
As stated earlier, the introduction of electric trains on the suburban rail network resulted in a reduction in fuel consumption for 2016, with PM10 emissions estimated at 3t/yr while NOx emissions were estimated at 154t/yr as shown in Table 5-5. These account for <1% of regional emissions from transport.
Table 5-5The results show that rail emissions increased from 2001 to 2011 along with fuel consumption, reduced in 2016 (due to the introduction of electric trains on the suburban rail network), and are projected to increase again to 2040 because of the increased growth in freight. Table 5-5 shows the estimated emissions from rail in the Auckland region for the years 2001 to 2016 and emission projections to 2040. Note, activity data for 2040 was assumed to be the same as 2041.
Auckland air emissions inventory 2016 – transport (revised) 40 The results also show that emissions from rail are a small source in the Auckland region, mainly because the amount of fuel used is minor compared to other sources such as motor vehicles and shipping (not included in this inventory). The electrification of the passenger rail network in Auckland has further reduced the amount of fuel consumed by this sector.
Table 5-5: Total annual emission estimates from rail for 2001 to 2016 and emission projections to 2040
Total annual emissions (t/yr) Pollutant 2001 2006 2011 2016 2026 2036 2040 Fuel consumption 4,113 6,983 9,552 2,600 2,555 2,871 3,021 CO 59 90 118 44 43 46 49
CO2 12,916 21,926 29,992 8,165 7,497 8,021 8,546 NOx 210 326 430 154 150 161 171
SO2 0.1 0.1 0.2 0.1 0.0 0.1 0.1
PM10 4.7 7.9 10.7 3.1 2.9 3.1 3.3
PM2.5 4.3 7.2 9.8 2.8 2.6 2.8 3.0 VOC 19.5 33.0 45.1 12.4 11.5 12.3 13.1
5.3 Uncertainty
The EMEP/EEA guidebook provides uncertainties for the Tier 2 emission factors for each pollutant as shown in Table 5-5. Fuel consumption estimates were provided by rail operators (Auckland Transport and KiwiRail) and should be reasonably accurate. The EMEP/EEA guidebook (EEA, 2016) states that the uncertainty in top-down activity data (fuel use) is likely to be in the order of five per cent whereas the uncertainty for bottom-up estimates (usage or fuel use by type of train) is unlikely to be less than 10%. For this assessment, activity data is based on a bottom-up estimate (from fuel burn rate and gross tonne kilometres). However, fuel usage rates were based on actual known fuel usage for New Zealand. The estimated activity data will have a higher uncertainty than a nationally reported fuel consumption estimate, however it will have a better accuracy than a bottom-up estimate. An uncertainty in fuel consumption of 10 per cent was assumed based on the lowest uncertainty suggested for a bottom-up assessment in the EMEP/EEA guidebook (EEA, 2016). Overall, the uncertainty associated with particulate emissions from rail was estimated according to Equation 2 as 150 per cent for freight and 264 per cent for passenger
Auckland air emissions inventory 2016 – transport (revised) 41 rail (see Section 9). This relatively high uncertainty is due to the high uncertainty associated with emission factors, which are not specific to the Auckland fleet.
Auckland air emissions inventory 2016 – transport (revised) 42 6.0 Road dust
Road dust is the generation and release of particulate matter into the air, mainly from the interaction between a vehicle’s wheels and the road surface, both on sealed and unsealed roads. Fine dust material is additionally created when vehicle wheels further grind down the road aggregate (Bluett et al., 2017). Road dust, particularly from unsealed roads, can create safety and health issues for road users and those living or working near the road. Airborne dust from roads has a range of particle sizes (Figure 6-1). This report only focuses on PM10 and PM2.5 and does not estimate road dust from coarser fractions which are largely associated with dust nuisance or amenity effects.
(Source: WHO, 2006). Figure 6-1: Size range of airborne dust.
There are 7300km of legal road in the Auckland region, of which approximately 868km (12%) is unsealed (AT, 2017). Most of the unsealed roads (78%) are in Rodney and the remaining 190km are found mainly in the Hauraki Islands, Franklin and Waitakere.
6.1 Unsealed road dust
The US EPA national air emissions inventory indicates that unsealed roads contribute 36 per cent of directly emitted annual PM10 emissions (US EPA, 2000).
Auckland air emissions inventory 2016 – transport (revised) 43 6.1.1 Activity data
VKT for the Auckland region was obtained from the NZ Transport Agency (NZTA, 2018). This provides total annual VKT for unsealed roads in the Auckland region.
Table 6-1: Total VKT on unsealed roads
Year 2015/16 2016/17 201619
Annual VKT 36,760,742 35,330,701 36,045,722
Additional data on unsealed roads in the Auckland region was extracted from the Road Assessment and Maintenance Management (RAMM) database by Auckland Transport. This data was used to calculate the proportion of unsealed roads located within the Auckland Urban Airshed compared to the whole region (excluding the islands in the Waitemata Harbour and Hauraki Gulf).
6.1.2 Emission factors
Emission factors for unsealed roads were calculated using the US EPA methodology, which is described below in Equation 7 (US EPA, 2006). This equation assumes vehicles travelling on the unsealed roads were predominantly light duty vehicles.
⁄ ⁄ Equation 7 ⁄ .
Where: E = size specific emission factor (lb/VMT), s = surface material silt content (%), M = surface material moisture content (%), S = mean vehicle speed (miles/hr), C = emission factor for 1980s vehicle fleet exhaust, brake wear and tyre wear (Table 6-4). In the above equation, the variables s and M are correction parameters to adjust the emission factors to local conditions. Table 6-2 shows the constants used in Equation 7 and are based on the stated aerodynamic particle sizes (US EPA, 2006). Quality ratings are also provided for each pollutant from US EPA.
19 VKT for 2016 was assumed to be the average of VKT for 2015/16 and 2016/17
Auckland air emissions inventory 2016 – transport (revised) 44 Table 6-2: Constants for Equation 7
Public roads
PM2.5 PM10 k (lb/VMT) 0.18 1.8 a 1 1 c 0.2 0.2 d 0.5 0.5 Quality rating B B
Table 6-3: Range of source conditions
Low Med High s (%) 0.1% 2% 15% M (%) 0.03% 6.50% 13% S (miles/h) 10 31 55
Table 6-3 shows the range of source conditions (low, medium and high) that were assumed for calculating emissions. The medium value for s (silt content) is the average of three measurements undertaken on unsealed roads in Northland (Metcalfe and Wickham, 2019). No other New Zealand specific values were available at the time of writing this report. The low and high values for silt content were from the reported range of typical values for public unpaved roads with gravel or crushed limestone surfaces in the Western Regional Air Partnership’s (WRAP) Fugitive Dust Handbook (WRAP, 2006). The source conditions for M (surface material moisture content) were based on the range of source conditions from US EPA 2006. The medium speed value of 31 miles per hour was based on speed measurements at one unsealed road in in Northland where an average speed of approximately 50km per hour was measured (Bluett et al., 2017). The low and high values for speed were based on the valid range of source conditions from US EPA 2006. Table 6-4 shows the default values for C used in Equation 7 (US EPA, 2006). Table 6-5 shows the emission factors derived using the equation constants (Table 6-2), the mid-range source conditions (Table 6-3), and the default emission factors for exhaust, brake and tyre (Table 6-4).
Auckland air emissions inventory 2016 – transport (revised) 45 Table 6-4: Default emission factors for 1980s vehicle fleet exhaust, brake and tyre wear
Particle size C range (lb/VMT)
PM2.5 0.00036
PM10 0.00047
Table 6-5: Calculated emission factors using mid-range conditions Emission Emission Particle size s M S (miles/hr) factor factor20 range (%) (%) (lb/VMT) (g/VKT)
PM2.5 2 6.5 31 0.018 5.1
PM10 2 6.5 31 0.182 51.4
For annual emissions, emission factors derived using Equation 7 can be extrapolated to annual average uncontrolled conditions (allowing for natural mitigation such as rainfall) based on the assumption that emissions are inversely proportional to the number of days in a year with measurable precipitation (i.e. days with greater than 0.254mm precipitation) as shown in Equation 8 (US EPA, 2006):
/ Equation 8
Where:
Eext = annual size specific emission factor extrapolated for natural mitigation (kg/VKT), E = emission factor from Equation 7 (kg/VKT), P = number of days in a year with at least 0.254mm of precipitation.
Precipitation data obtained for areas outside the Auckland Urban Airshed21 are shown in Table 6-6, except for Albany and Henderson. These two sites are located
20 Emission factors were converted from lb/VMT (as per the US EPA methodology) to g/VKT based on 1 lb/VMT = 281.9 g/VKT. 21 Most unsealed roads (93%) are outside of the Auckland Urban Airshed (not including Waiheke Island or Great Barrier Island).
Auckland air emissions inventory 2016 – transport (revised) 46 on the outer bounds of the Auckland Urban Airshed and Henderson site is assumed to be representative of the localised weather in the Waitakere Ranges (west Auckland). The average from these five sites was used to determine annual precipitation.
Table 6-6: Precipitation and soil moisture for 2016 No. days Location >0.2 mm* Leigh 157
Warkworth 168
Albany 157
Henderson 180
Pukekohe 154 (Source: NIWA, 2017). * Measurable precipitation days assumed > 0.2mm (instead of 0.254mm).
6.1.3 Results
Annual PM2.5 and PM10 emissions from unsealed road dust are estimated to be 101t/yr and 1024t/yr respectively based on the default source conditions, medium VKT and average precipitation for Auckland. The annual estimates are further influenced by the number of measurable days of precipitation and can range between
939t/yr of PM10 (for high precipitation days) to 1071t/yr (for low precipitation days). The results presented here are only indicative as they are heavily dependent upon the quality and availability of local data (see section 6.1.4 on Uncertainty).
6.1.3.1 Sensitivity
Estimated emissions from unsealed roads are highly sensitive to changes in surface material silt content and surface moisture content. Emissions were estimated under the lower and upper bounds of the default range to test the sensitivity of the emission factor (and therefore resulting emissions): Sensitivity 1: Surface silt material content = Low; all other conditions = Med. Surface silt material content = High; all other conditions = Med. Sensitivity 2: Surface moisture content = Low; all other conditions = Med. Surface moisture content = High; all other conditions = Med.
Auckland air emissions inventory 2016 – transport (revised) 47 The results from this analysis are shown in Table 6-7.
Table 6-7: Sensitivity analysis for unsealed roads
Sensitivity PM10 (t/yr) PM2.5 (t/yr)
Low High Low High
Surface silt material content % 48.70 7,698.79 3.11 768.12 % difference from medium settings ‐95% 652% ‐97% 663%
Surface moisture content (%) 3,008.07 891.29 299.05 87.37 % difference from medium settings 194% ‐13% 197% ‐13%
6.1.4 Uncertainty
6.1.4.1 Emission factor uncertainty
Quality ratings are provided by the US EPA (Table 6-2) for each pollutant. US EPA guidance (US EPA, 2006) states that the default values can be used if site specific values for correction parameters are not available. However, if the default value for silt content is used, then the quality rating of the equation is reduced by two (i.e. the current B rating will drop to a D rating) (US EPA, 2006). We used a site specific value for silt content, however this was based on just three measurements in Northland. There was no data available for Auckland, so we assumed that the quality rating of the emission factor was the same as the rating for the default value. Similarly, the mid-range moisture content value was based on US data. The US EPA suggests downgrading the quality rating by two letters if the default moisture content value is used. This means the quality rating for the equation was potentially an F rating. The sensitivity analysis showed that emission estimates were up to 97 per cent lower or 663 per cent higher than the mid-range estimate of emissions depending on the assumptions made in deriving emission factors.
6.1.4.2 Activity data uncertainty
VKT data for unsealed roads was obtained from NZ Transport Agency. There was no information available on the uncertainty associated with this data. For this analysis we assumed that the uncertainty was the same as the uncertainty for motor vehicle VKT on all roads. As discussed in Section 3.3.3 it was estimated that VKT for all roads had an uncertainty of ±21% and ±23% for petrol and diesel vehicles respectively. For unsealed roads VKT, we assumed an average uncertainty of ±22%.
Auckland air emissions inventory 2016 – transport (revised) 48 6.1.4.3 Overall uncertainty
For this analysis it was assumed that emission factor uncertainty was 663 per cent and activity data uncertainty was 22 per cent. Overall, the uncertainty associated with unsealed road dust was calculated according to Equation 2 as approximately 663 per cent (see Section 9).
6.2 Road surface wear (sealed roads)
There is very little information on airborne particle emissions from road surface wear (EEA, 2016). The emissions estimated in this section are only for completeness. Please note, the overall estimates are highly uncertain.
6.2.1 Activity data
VKT data, by vehicle type, for sealed roads is provided in Table 3-1 (see Section 3.1.1 on Motor vehicles).
6.2.2 Emission factors
Emission factors from EMEP/EEA guidebook are shown in Table 6-8.
Table 6-8: TSP Emission factors from road surface wear
Vehicle category Emission factor (g/km) Quality code Two-wheel vehicles 0.0060 C-D Passenger vehicles 0.0150 C-D Light-duty trucks 0.0150 C-D Heavy-duty trucks 0.0760 C-D (Source: EEA, 2016). Quality codes: C: emission factors estimated based on available literature. D: Emission factors estimated applying similarity considerations and/or extrapolation.
The mass fraction of TSP in the different particle size classes is shown in Table 6-9.
Auckland air emissions inventory 2016 – transport (revised) 49 Table 6-9: Size distribution of road surface wear particles
Particle size class Mass fraction of TSP TSP 1.0
PM10 0.5
PM2.5 0.27 (Source: EEA, 2016).
6.2.3 Results
Estimated emissions of particulate from sealed road wear are shown in Table 6-10 for all years.
Table 6-10: Estimated emissions from sealed road wear
Total annual emissions (t/yr) Pollutant 2001 2006 2011 2016 2026 2036 2040
PM10 92 105 109 118 143 159 162
PM2.5 49 57 59 64 77 86 89
6.2.4 Uncertainty
Emission factors for sealed road wear are based on limited information and are highly uncertain (EEA, 2016).
6.2.4.1 Emission factor uncertainty
Quantitative uncertainty ranges for emission factors are not available. For this assessment, it was assumed that the margin of error for all emission factors was 300 per cent based on the typical error ranges provided in the EMEP/EEA guidebook (EEA, 2016).The highest estimated uncertainty for “an estimate based on single measurements, or an engineering calculation derived from a number of relevant facts” is 300 per cent as shown in Table 2-1.
6.2.4.2 Activity data uncertainty
Total VKT on sealed roads was obtained from the Auckland Regional Transport model and uncertainty was assumed to be approximately ± 10%.
6.2.4.3 Overall uncertainty
Overall, the uncertainty associated with particulate emissions from road wear was calculated according to Equation 2 as approximately 300 per cent (see Section 9).
Auckland air emissions inventory 2016 – transport (revised) 50 7.0 Off-road vehicles and lawn mowers
This section reports on off-road vehicles (e.g., equipment, machinery and vehicles used for industrial activities) and lawn mowers. Emissions from off-road vehicles have been estimated using the same methodology as the previous inventory (Auckland Council, 2014a) with updated fuel consumption data from the Energy Efficiency and Conservation Authority (EECA) energy use database. Emissions from lawn mowers were estimated based on the EMEP/EEA guidebook Tier 1 methodology for non-road mobile machinery (household and gardening).
7.1 Off-road vehicles
Emissions are estimated by using the Australian National Pollutant Inventory (NPI) methodology for industrial vehicles (Australian Department of the Environment, Water, Heritage and the Arts, 2008) as described in Equation 9:
Equation 9
Where: E = Emission of a pollutant for a specific equipment type (kg/year), DU = Diesel use for the specific equipment type (litre/year), LF = Load factor for the specific equipment type (shown in Table 7-1), EF = Emission factor of the pollutant for the specific equipment type (kg/litre).
Table 7-1: Load factors for vehicles
Vehicle type Load factor Miscellaneous (default) 0.50 Track type tractor 0.55 Wheeled tractor 0.55 Wheeled dozer 0.55 Scraper 0.50 Motor grader 0.50 Wheeled loader 0.50 Track type loader 0.50 Off-highway truck 0.50 Roller 0.50 (Source: Australian Department of the Environment, Water, Heritage and the Arts, 2008).
Auckland air emissions inventory 2016 – transport (revised) 51 7.1.1 Activity estimate
The EECA energy use database provides estimated fuel consumption for “non- transport, motive power, mobile” (Table 7-2). This is defined as any source of energy used to produce motion including off-road (excludes on-road transport) machinery used in construction, mining, agriculture (e.g. tractors and trucks). Table 7-2: Diesel delivery estimates for non-transport, motive power, mobile in Auckland for 2012 shows diesel delivery estimates for non-transport, motive power and mobile sources in Auckland for 2012.
Table 7-2: Diesel delivery estimates for non-transport, motive power, mobile in Auckland for 2012
Energy Energy Year Sector End-use delivered delivered % of total (TJ) (litres diesel)
2012 Construction Motive power, mobile 1,079.45 28,026,338 29%
2012 Mining Motive power, mobile 220.481 5,724,471 6%
2012 Agriculture Motive power, mobile 567.492 14,734,112 15%
2012 Forestry Motive power, mobile 132.664 3,444,430 4%
2012 Other Motive power, mobile 1,763.39 45,783,906 47%
2012 Total Motive power, mobile 3763.477 97,713,257 (Source: EECA, 2016).
The EECA database only provides regional data for 2012. The national totals for diesel delivery, non-transport, motive power, mobile increased by approximately 1.2% per annum between 2012 and 2015. Diesel deliveries for Auckland in 2016 have been estimated as approximately 105 per cent of 2012 consumption figures based on the annual increase in national deliveries between 2012 and 2015 (Table 7-3).
Auckland air emissions inventory 2016 – transport (revised) 52 Table 7-3: Diesel delivery estimates for non-transport, motive power, mobile in Auckland estimated for 2016 based on 2012 data
Energy Energy Year Sector End-use delivered delivered % of total (TJ) (litres diesel)
2016 Construction Motive power, mobile 1,132 29,384,298 29%
2016 Mining Motive power, mobile 231 6,001,839 6%
2016 Agriculture Motive power, mobile 595 15,448,024 15%
2016 Forestry Motive power, mobile 139 3,611,323 4%
2016 Other Motive power, mobile 1,849 48,002,274 47%
2016 Total Motive power, mobile 3,946 102,447,759 (Source: EECA, 2016).
7.1.1.1 Projections and previous years
The EECA databased provides fuel consumption estimates for 2012 only. For previous years, fuel consumption was estimated based on national trends in off-road diesel consumption (Table 7-4). Fuel consumption for 2001 and 2006 was calculated as a proportion of 2016 fuel consumption. National trends from the industrial sector were used to estimate Auckland fuel consumption for construction, mining and “other” sectors. National trends from agriculture, forestry and fishing were used to estimate Auckland fuel consumption for Agriculture and Forestry sectors. There was a clear upward trend in diesel consumption from the land transport sector between 2001 and 2016 (Table 7-4). However, there was no clear or consistent trend in diesel consumption from other sectors. There was no other information available to develop fuel consumption projections for off-road vehicles, so it was assumed that fuel consumption does not change in future years.
Table 7-4: Diesel consumption trends by sector for New Zealand
Sector 2001 2006 2011 2016
Diesel consumption as % of 2016 consumption
Land transport 64% 79% 88% 100%
Agriculture, forestry, fishing 99% 111% 91% 100%
Industrial 67% 96% 73% 100% (Source: MBIE, 2017).
Auckland air emissions inventory 2016 – transport (revised) 53 Table 7-5: Australian NPI emission factors (g/litre) for diesel exhaust emissions of industrial vehicles
Track type Wheeled Wheeled Wheeled Track type Off-highway Scraper Roller Miscellaneous tractor tractor dozer loader loader truck
g/litre rating g/litre rating g/litre rating g/litre rating g/litre rating g/litre rating g/litre rating g/litre rating g/litre rating
CO 9.6 E 32.3 U 15.0 U 10.2 U 6.7 D 9.9 U 14.6 U 24.3 U 18.6 E NOx 33 E 52.8 U 35.2 U 31 U 30.7 D 39.6 U 34.1 U 54 U 45 E
PM10 3.1 E 5.6 U 1.76 U 3.4 U 2.7 D 2.9 U 2.1 U 3 U 3.6 E
SO2 0.02 U 0.02 U 0.02 U 0.02 U 0.02 U 0.03 U 0.02 U 0.026 U 0.024 U VOC 3.3 E 7.92 U 1.6 U 2.3 U 1.6 D 4.9 U 1.6 U 3.9 U 4.2 E
(Source: Australian Department of the Environment, Water, Heritage and the Arts, 2008). Emission factor rating system is: A Excellent B Above average C Average D Below average E Poor U Unrated
Auckland air emissions inventory 2016 – transport (revised) 54 7.1.2 Emission factors
To estimate emissions from off-road vehicles, emission factors for industrial vehicles from the Australian NPI (Australian Department of the Environment, Water, Heritage and the Arts, 2008) are used (Table 7-5). Vehicle types For the construction sector, vehicle type was based on the results of a Ministry of Transport survey. This survey estimated diesel fuel use information for construction vehicles for the whole country in 2008 (MoT, 2008). This survey estimated off-road diesel construction by equipment type (Table 7-6).
Table 7-6: Off-road diesel consumption by vehicle type in the construction sector
Vehicle type % diesel use Vehicle type % diesel use Excavator 46.4 Compactor 0.2 Loader 6.4 Roller/paver 4.8 Grader 9.8 Crusher 2.5 Dump truck 9.5 Compressor 0.6 Scraper 3.6 Piling equipment 4.4 Dozer 6.4 Crane 3.9 Tractor 0.9 Water cart/broom 0.6
(Source: MoT, 2008). These vehicle types from the NZ survey were matched to the closest industrial vehicle type in the Australian NPI Table 7-7.
Auckland air emissions inventory 2016 – transport (revised) 55 Table 7-7: Construction vehicle type matched to vehicle categories provided in the Australian industrial vehicle emission factors
Australian NPI Australian NPI NZ survey vehicle NZ survey vehicle industrial vehicle industrial vehicle type type category category Track type tractor or Excavator Compactor Miscellaneous wheeled dozer Track type loader or Loader Roller/paver Roller wheeled dozer
Grader Motor grader Crusher Miscellaneous
Dump truck Off-highway truck Compressor Miscellaneous
Scraper Scraper Piling equipment Miscellaneous
Track type tractor or Dozer Crane Miscellaneous wheeled dozer
Tractor Wheeled dozer Water cart/broom Miscellaneous
(Source: Australian Department of the Environment, Water, Heritage and the Arts, 2008).
There was no specific information about vehicle types used in other sectors. The vehicle types shown in Table 7-8 were assumed.
Table 7-8: Australian industrial vehicle emission factors assumed for each sector
Sector Australian industrial vehicle category
Mining Assume the same as construction sector
Agriculture Wheeled tractor
Forestry Assume the same as construction sector
Other Miscellaneous
7.1.2.1 Projections and other years
There was very little information about the types of vehicles and emissions from the existing fleet and there were no emission factors available for off-road vehicles for other years. Off-road vehicles are not subject to the same emissions regulations as on-road vehicles. For other years it was assumed that emission factors were the same as 2016.
Auckland air emissions inventory 2016 – transport (revised) 56 7.2 Lawn mowers
7.2.1 Activity data
Petrol consumption from lawn mowers has been estimated by MoT at 10 to 12 litres per annum per mower, with approximately one mower per 1.5 households (MoT, 2017). This may overestimate fuel consumption in the Auckland Urban Airshed where intensification has seen the number of households increase, while the area of gardens has probably decreased. However, this is a very small source of emissions and no detailed information was available to improve on the Ministry of Transport estimate. The lower estimate of 10 litres of petrol per mower per annum and one mower per 1.5 households was assumed. Based on the number of households in the 2013 census (471,837), fuel consumption from lawn mowers was estimated as 3.1 million litres of petrol per annum. This equates to 0.3% of regional total petrol consumption.
7.2.1.1 Projections and other years
Lawn mowers were a minor source of emissions for 2016, so other years and projections assumed that activity rates do not change.
7.2.2 Emission factors
Tier 1 emission factors from the EMEP/EEA guidebook were used for household and gardening non road mobile machinery (Table 7-9). There were no data on the proportion of 2-stroke vs 4-stroke lawn mowers. The Auckland air emissions inventory for 1993 assumed an equal split between 2-stroke and 4-stroke lawn mowers and expected a gradual shift towards 4-stroke over 2-stroke lawn mowers (EPA Victoria, 1998). New lawn mowers commonly available in the market confirmed that new lawn mowers are generally 4-stroke. Therefore, for this inventory, a split of 80 per cent four-stroke and 20 per cent two-stroke was assumed. This is an approximation based on the assumption that most lawnmowers will now be four- stroke. There is no information available to improve this estimate, and given that lawnmowers are a very small source of emissions, improvement of this estimate is unlikely to be a priority for future work. For sulphur dioxide, the emission factor was calculated based on the sulphur content of petrol as described in the motor vehicles section of this report.
Auckland air emissions inventory 2016 – transport (revised) 57 7.2.2.1 Projections and other years
Lawn mowers were a minor source of emissions for 2016, so other years and projections assumed that emission factors do not change.
Table 7-9: Emission factors for lawn mowers
2-stroke 4-stroke Pollutant g/tonne fuel g/tonne fuel CO 620,793 770,368 NOx 2,765 7,117
PM10 3,762 157
SO2 100 100 VOC 227,289 18,893
7.3 Results
Estimated emissions for off-road vehicles and lawn mowers in 2016 are shown in Table 7-10 and Table 7-11 respectively.
Table 7-10: Estimated emissions from off-road vehicles for 2016
Sector Total Pollutant Construction Mining Agriculture Forestry Other Fuel 29,384 6,002 15,448 3,611 48,002 102,448 (litres/yr) CO (t/yr) 206 42 275 25 446 993
CO2 (t/yr) 78,456 16,024 41,246 9,642 128,166 273,536 NOx (t/yr) 560 114 449 69 1,080 2,272
SO2 (t/yr) 0.4 0.07 0.2 0.05 0.5 1.2
PM10 (t/yr) 40 8 48 4.9 86 188 VOC (t/yr) 37 8 45 5 79 173
Auckland air emissions inventory 2016 – transport (revised) 58 Table 7-11: Estimated emissions from lawn mowers for 2016
Total Pollutant (t/yr) Fuel consumption 2,331 CO 1,726
CO2 7,452 NOx 141
SO2 15
PM10 2 VOC 2
7.3.1 Projections and other years
Lawnmower emissions were not estimated for other years. Emissions were assumed to be similar for all years. Estimated emissions from off-road vehicles for other years are summarised in Table 7-12. There was no information available to develop a robust projection for off-road vehicle emissions. There may be an increase in activity over time with increasing population. However, emissions are likely to reduce with improvements in energy efficiency and emissions control. In the absence of specific data, it was assumed that off-road vehicle emissions do not change in future years.
Table 7-12: Total annual emissions estimates from off-road vehicles for 2001 to 2016 and emission projections to 2040
Total annual emissions (t/yr) Pollutant 2001 2006 2011 2016 2026 2036 2040 Fuel consumption 55,120 75,275 57,922 75,914 CO 758 1,002 779 994
CO2 198,610 271,233 208,708 273,536
NOx 1,680 2,266 1,750 2,272 no change from 2016 SO2 1 1 1 1
PM10 142 188 146 188
PM2.5 131 174 135 173 VOC 171 224 175 221
Auckland air emissions inventory 2016 – transport (revised) 59 7.4 Uncertainty
According to the EMEP/EEA guidebook (EEA, 2016), the estimation of emissions from off-road vehicles is subject to large uncertainties due to lack of information on vehicle and machinery population, emission factors, and conditions of use.
7.4.1 Emission factor uncertainty
Quantitative uncertainty ranges for off-road motor vehicle emission factors are not available. Emission factor ratings (Table 7-5) do not imply statistical error bounds or confidence intervals. Most factors have a rating of E (poor) or U (unrated). For this assessment, it was assumed that the margin of error for all emission factors is 200 per cent based on the typical error ranges provided in the EMEP/EEA guidebook (EEA, 2016). As shown in Table 2-1 (section 2.1 on uncertainty) 200 per cent is the mid-range estimate for “an estimate based on single measurements, or an engineering calculation derived from a number of relevant facts”. An uncertainty of 200 per cent is considered appropriate in this case where the emission factors have been developed based on a limited number of measurements, which are applied to a broad range of vehicle types. Emission factors for lawn mowers are rated as E in the EMEP/EEA guidebook. As shown in Table 2-1 (see section 2.1) emission factors with an E rating typically have an error range of an order of magnitude (so the emission factor could be an order of magnitude higher than the default emission factor). On this basis, an emission factor uncertainty of 500 per cent was assumed for this assessment.
7.4.2 Activity data uncertainty
Activity data are based on fuel consumption from the EECA energy use database. Uncertainty estimates are not provided for the EECA database; however, the estimated fuel consumption is based on best available information and is expected to be within ± 30%. Lawnmower activity data was estimated based on an approximate national level estimate. The uncertainty associated with this was assumed to be 100 per cent based on the highest indicative uncertainty for activity data suggested by EMEP/EEA guidebook (EEA, 2016).
Auckland air emissions inventory 2016 – transport (revised) 60 7.4.3 Overall uncertainty
Overall, the uncertainty associated with off-road vehicle emissions of PM10 was estimated according to Equation 2 as approximately 202 per cent (see Section 8).
The uncertainty associated with lawnmower emissions of PM10 was estimated according to Equation 2 as approximately 510 per cent (see Section 9).
Auckland air emissions inventory 2016 – transport (revised) 61 8.0 Road laying
VOC emissions from road laying were estimated in the 1993 emissions inventory for Auckland (EPA Victoria, 1998). For this update, emissions from road laying for 2016 were pro-rated from the 1993 emissions inventory based on bitumen use trends at the national level (MfE, 2016).
8.1 Methodology
Emissions of VOC from road laying were estimated in the 1993 emissions inventory based on information from the New Zealand Bitumen Contractor’s Association. Estimated emissions have been scaled up for the 2016 inventory based on the estimated increase in asphalt consumption since 1993, assuming that the emissions of VOC per tonne of bitumen consumed have not changed.
8.2 Activity data
The New Zealand greenhouse gas inventory reports the quantity of asphalt used per annum in New Zealand. The fraction by weight of bitumen in road paving material has reduced over time as road laying methods have improved (Table 8-1) (MfE, 2016).
Table 8-1: Fraction of bitumen in road paving material
Reporting period Fraction of bitumen 1990-2001 0.80 2002-2003 0.65 2004-2015 0.60
According to the 2014 New Zealand greenhouse gas inventory, the quantity of asphalt used in New Zealand in 1993 was 115kt (MfE 2016). Assuming an 80 per cent fraction of bitumen in asphalt, the national consumption of bitumen was approximately 92kt in 1993. The emissions inventory for Auckland (EPA Victoria, 1998) reported bitumen consumption as 22.35kt in 1993 which was approximately 24 per cent of the national total.
Auckland air emissions inventory 2016 – transport (revised) 62 Table 8-2: Reported and estimated bitumen consumption
Quantity of Fraction of Quantity of Year asphalt bitumen in bitumen (kt) asphalt (kt)
New Zealand1 1993 115 0.8 92 Auckland2 1993 22
New Zealand1 2015 201 0.6 121
New Zealand3 2016 209 125
Auckland4 2016 31 1 MfE (2016). 2 EPA Victoria (1998). 3 Extrapolated. 4 Pro-rated from the New Zealand total.
Bitumen consumption for New Zealand in 2016 was estimated as 125kt per annum based on extrapolation of asphalt production figures from 1993 to 2015. Bitumen consumption for 2016 in Auckland was estimated as 31kt, which is 24 per cent of the estimated New Zealand national total.
8.3 Results
VOC emissions for Auckland were estimated based on the estimated bitumen consumption in 1993 and 2016 (Table 8-3). Emissions for other years were interpolated. No information was available to develop a projection, so it was assumed that emissions do not change in future years.
Table 8-3: Estimated VOC emissions from road laying
Quantity of VOC Emissions Year bitumen (tonne/annum) (kt) 19931 22 189 2001 213 2006 228 2011 243 20161 31 258 all future years 258 1 Estimated.
Auckland air emissions inventory 2016 – transport (revised) 63 8.4 Uncertainty
The New Zealand Greenhouse Gas Inventory (MfE, 2016) estimates the uncertainty of asphalt activity data and VOC emission factors as ±40% at a national level. Reliable figures for regional bitumen and cutter oil consumption were obtained for the 1993 inventory, however these have not been updated. It was assumed that the regional emission factors have a similar level of uncertainty to the national emission factors. It was assumed that the regional activity estimate would have a somewhat higher level of uncertainty compared to the national estimate of ±40%, because it relies on assumptions about the proportion of national asphalt consumption that occurs in Auckland. Uncertainty was estimated at ±40% for emission factors and ±60% for activity data resulting in an overall uncertainty of approximately ±70% (see Section 9).
Auckland air emissions inventory 2016 – transport (revised) 64 9.0 Overall results and uncertainty
This section presents a summary of results for 2016 and the overall assessment of uncertainty. Summary results for each year 2001-2040 are provided in Appendix A.
9.1.1 Overall results
In 2016, PM10 emissions from transport (excluding shipping) were estimated at 1991t/yr in the Auckland region. Dust generated from unsealed roads accounted for approximately half of these emissions (51%), while approximately 32 per cent of emissions were from motor vehicles, and nine per cent of emissions from off-road vehicles. PM2.5 emissions were estimated at 940t/yr in the region from transport emissions, with motor vehicles contributing almost 63 per cent of emissions, while off-road vehicles and road dust from unsealed roads accounted for approximately 18 per cent and 11 per cent of regional PM2.5 emissions. For NOx, total emissions for 2016 were estimated as 15,286t/yr, where motor vehicles accounted for 67 per cent of the regional emissions, and aircraft and off- road mobile sources accounting for 17 per cent and 15 per cent of regional emissions respectively.
45,185t/yr CO (91% motor vehicles, 4% lawn mowers, 3% aircraft)
3,930kt/yr CO2 (81% motor vehicles, 12% aircraft, 7% off-road vehicles) 15,286t/yr NOx (67% motor vehicles, 17% aircraft, 15% off-road vehicles)
1,991t/yr PM10 (51% unsealed road dust, 32% motor vehicles, 9% off- road vehicles)
940t/yr PM2.5 (63% motor vehicles, 18% off-road vehicles, 11% unsealed road dust)
196t/yr SO2 (62% aircraft, 37% motor vehicles) 4,024t/yr VOCs (80% motor vehicles, 6% off-road vehicles, 4% aircraft, 4% lawn mowers). Motor vehicles are the most significant source of emissions across all pollutants within the Auckland Urban Airshed except for SO2 (see Table A-8 in Appendix A).
Emissions from the airport are estimated to contribute towards 71 per cent of SO2 emissions within the Auckland Urban Airshed.
9.1.2 Overall assessment of uncertainty
The uncertainty associated with each source was estimated and reported in each section of this report. Based on the EMEP/EEA Tier 1 methodology, the overall uncertainty associated with the inventory of PM10 emissions from transport (excluding
Auckland air emissions inventory 2016 – transport (revised) 65 shipping) was estimated as approximately 342 per cent for the Auckland region. Table 9-1 shows the uncertainty associated with the activity data and emission factor for each source, and the overall calculated uncertainty for all sources in the region. This shows that the uncertainty associated with the overall emissions inventory is dominated by the uncertainty associated with unsealed road dust emissions.
Table 9-1: Uncertainty calculated for each source and overall uncertainty for the Auckland region.
(2016) data factor
total
uncertainty uncertainty
Source Fuel of
emissions
%
Pollutant uncertainty uncertainty (kg/annum) as Activity 2016 Emission emissions Combined Combined
Car Petrol PM10 E 49,111 21% 100% 102% 3%
Light commercial Petrol PM10 E 1,259 21% 100% 102% 0.06% Hybrid and Petrol PM E 0 21% 100% 102% 0% Electric 10
Car Diesel PM10 E 90,148 23% 48% 53% 2%
Motor Light commercial Diesel PM10 E 216,529 23% 34% 41% 4% vehicles Bus Diesel PM10 E 9,098 23% 100% 103% 0%
Heavy Diesel PM10 E 153,392 23% 100% 103% 8%
Car PM10 B&T 93,303 10% 44% 45% 2%
Light commercial PM10 B&T 21,433 10% 38% 40% 0%
Heavy PM10 B&T 12,244 10% 38% 40% 0% Subtotal 31%
Aviation PM10 9,658 3% 20% 20% 0%
Freight Diesel PM10 2,605 10% 150% 150% 0%
Rail Passenger Diesel PM10 473 10% 264% 264% 0% Subtotal 134% Road dust PM 1,024,217 22% 663% 663% 341% unsealed 10 Sealed road PM 117,789 10% 300% 300% 18% wear 10 Off‐road motor Diesel PM10 187,522 30% 200% 202% 19% vehicles
Lawn mowers Petrol PM10 2,047 100% 500% 510% 1% Total emissions 1,990,829 Uncertainty total 342% For the Auckland Urban Airshed, the overall uncertainty associated with the inventory of PM10 emissions from transport (excluding shipping) was estimated as approximately 88 per cent. Table 9-2 shows the uncertainty associated with the activity data and emission factor for each source, and the overall calculated uncertainty for all sources in the Airshed. Although unsealed road dust emissions are
Auckland air emissions inventory 2016 – transport (revised) 66 a relatively minor source of PM10 emissions within the Auckland Urban Airshed, this analysis shows that the uncertainty associated with the PM10 emissions inventory within the Airshed is dominated by the very high uncertainty associated with unsealed road dust emissions.
Table 9-2: Uncertainty calculated for each source and overall uncertainty in the Auckland Urban Airshed.
(2016) data factor
total
uncertainty uncertainty
Source Fuel of
emissions
%
Pollutant uncertainty uncertainty (kg/annum) as Activity 2016 Emission emissions Combined Combined
Car Petrol PM10 E 33,355 21% 100% 102% 6%
Light commercial Petrol PM10 E 855 21% 100% 102% 0.14% Hybrid and Petrol PM E 0 21% 100% 102% 0% Electric 10
Car Diesel PM10 E 61,226 23% 48% 53% 5% 147,060 Motor Light commercial Diesel PM10 E 23% 34% 41% 10% vehicles Bus Diesel PM10 E 6,179 23% 100% 103% 1%
Heavy Diesel PM10 E 104,179 23% 100% 103% 17%
Car PM10 B&T 63,369 10% 44% 45% 5%
Light commercial PM10 B&T 14,557 10% 38% 40% 1%
Heavy PM10 B&T 8,316 10% 38% 40% 1% Subtotal 31%
Aviation PM10 9,658 3% 20% 20% 0%
Freight Diesel PM10 507 10% 150% 150% 0%
Rail Passenger Diesel PM10 92 10% 264% 264% 0% Subtotal 134% Road dust PM 71,695 22% 663% 663% 77% unsealed 10 Sealed road PM 75,874 10% 300% 300% 37% wear 10 Off‐road motor Diesel PM10 21,737 30% 200% 202% 7% vehicles
Lawn mowers Petrol PM10 237 100% 500% 510% 0% Total emissions 618,898 Uncertainty total 88%
Auckland air emissions inventory 2016 – transport (revised) 67 10.0 Conclusions and recommendations
Total regional emissions of PM10 and NOx from transport in 2016 were estimated as 1991 and 15,473t/yr, respectively. Motor vehicles continue to be the most significant source of transport air pollution in the Auckland region. It was estimated that on-road motor vehicles contribute 10,251t/yr of NOx and 647t/yr of PM10. Emissions from motor vehicles represent 67 per cent of total regional NOx emissions and 32 per cent of total regional PM10 emissions from transport in the Auckland region. Within the Auckland Urban Airshed, emissions from motor vehicles account for 71 percent of total NOx emissions and 71 per cent of total PM10 emissions.
In this 2016 inventory, the estimated transport emissions of PM10 include dust from sealed and unsealed roads. These sources account for nine per cent and 51 per cent of estimated PM10 emissions in the region, respectively. Within the Auckland Urban Airshed, dust from sealed roads and dust from unsealed roads account for 12 per cent each of PM10 emissions. The inventory includes projections out to 2040. For motor vehicles, the projections show that, despite a predicted increase in VKT, there is generally a predicted decrease in vehicle emissions over time. This is due to improvements in new vehicle technology. It is expected that emissions from the fleet will gradually reduce as new (lower emission) vehicles are introduced into the fleet and older (higher emission) vehicles are retired from the fleet. However, it is important to note the limitations of these projections. In particular:
The projections are based on projections from the ART model and VEPM. Each of these models is based on current knowledge and expectations, however they are based on assumptions and have significant uncertainty.
Continuous monitoring, validation and review of progress against targets is critical. The importance of this has been illustrated in Europe where predicted
reductions in ambient NO2 concentrations have not been measured in real life. Researchers have found that this difference between models and reality is due to the growing gap between legal vehicle emission limits and vehicle emissions in the real world (see for example ICCT, 2017). Comparison of fuel consumption with regional fuel sales figures suggests that the inventory may underestimate emissions from motor vehicles by at least 20%. Improving emissions and fuel consumption estimates from the inventory and the vehicle emissions prediction model (VEPM) is a recommended priority for future research.
Auckland air emissions inventory 2016 – transport (revised) 68 This 2016 inventory includes an approximate quantitative analysis of uncertainty based on the EMEP/EEA guidebook Tier 1 methodology. This methodology is consistent with the IPCC methodology for greenhouse gas emission inventories. The main purpose of this uncertainty analysis was to identify the sources that contribute most to uncertainty rather than necessarily producing an accurate estimate of statistical uncertainty. Based on the EMEP/EEA guidebook Tier 1 methodology and the assumptions stated in each section of this report, the overall uncertainty in PM10 emissions in the Auckland Region was estimated as 342 per cent. The estimated uncertainty of each source as a percentage of total emissions gives an indication of the relative contribution of each source to overall uncertainty. The uncertainty as a percentage of emissions was estimated as 341 per cent for unsealed road dust, 19 per cent for off-road vehicles, 18 per cent for motor vehicle exhaust, and 18 per cent for sealed road dust.
The most significant source of uncertainty in the PM10 emissions inventory was unsealed road dust, which occurs primarily outside the Auckland Urban Airshed. The overall uncertainty in PM10 emissions within the Auckland Urban Airshed was substantially lower at 88 per cent. The uncertainty of the PM10 emissions inventory could be substantially reduced by collection of local data to improve unsealed road emission factors. This data should include silt content and surface moisture content as well as speed estimates for unsealed roads in Auckland.
Auckland air emissions inventory 2016 – transport (revised) 69 11.0 References
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Auckland air emissions inventory 2016 – transport (revised) 70 EFRU, 2008. Development of a vehicle emissions prediction model. Report prepared for Auckland Regional Council (now Auckland Council) by Energy and Fuels Research Unit, Auckland University. Environment Australia, 1999. Emissions Estimation Technique Manual for Aggregated Emissions from Railways. http://www.npi.gov.au EPA Victoria, 1998. Auckland Air Emissions Inventory. Prepared for Auckland Regional Council. Auckland Regional Council technical publication, TP91 Golder, 2014. The comparison of modelled and on-road light duty vehicle emission factors. Report prepared by Golder Associates for NZ Transport Agency and Auckland Council. January 2014 ICCT, 2017. Road tested: Comparative overview of real world versus type-approval NOx and CO2 emissions from diesel cars in Europe. ICCT White Paper. September 2017 Kar K, Baral B and Elder S, 2008. Development of a Vehicle Emission Prediction Model. Prepared by the Energy and Fuels Research Unit, University of Auckland for the Auckland Regional Council. December 2008 KiwiRail, 2016. Annual integrated report 2016. Prepared by KiwiRail MBIE, 2010. Reviewing aspects of the Engine Fuel Specification Regulations 2008. Discussion paper prepared by the (former) Ministry for Economic Development (now Ministry for Business, Innovation and Employment) MBIE, 2017. Energy in New Zealand 2017. Data tables available at www.mbie.govt.nz Metcalfe J, Bluett J and Kuschel G, 2013. Comparison of trends in predicted (VEPM) and real-world (RSD) emissions for the light duty fleet – 2003 to 2011, Report prepared by for NZ Transport Agency, December 2013 Metcalfe J and Sridhar S, 2017. VEPM 5.3 Vehicle Emission Prediction Model update: Technical report. Report for New Zealand Transport Agency prepared by Emission Impossible Ltd, April Metcalfe J, Wickham L and Sridhar S, 2018. Auckland air emissions inventory 2016 – home heating. Prepared by Emission Impossible Ltd for Auckland Council. Auckland Council technical report, TR2018/018
Metcalfe J and Wickham L, 2019. Health impacts of PM10 from unsealed roads in Northland. Prepared by Emission Impossible Ltd for Ministry of Health [in press]
Auckland air emissions inventory 2016 – transport (revised) 71 MfE, 2016. New Zealand’s Greenhouse Gas Inventory 1990-2014. Prepared by the Ministry for the Environment. Wellington MoT, 2008. Use of Diesel by Non-Road Vehicles in the Construction Sector. Report prepared by John Edgar Consulting for Ministry of Transport MoT, 2016. Auckland Transport Alignment Project – Foundation report. Prepared by the Ministry of Transport, The Treasury, Auckland Council, Auckland Transport, State Services Commission and NZ Transport Agency MoT, 2018. Auckland Transport Alignment Project 2018 [MoT website]. Available at: https://www.transport.govt.nz/land/auckland/atap/ NIWA, 2017. The National Climate Database. CliFlo Database, National Institute for Water and Atmosphere Nunns P, 2015. Statement of Evidence – Peter Nunns on Behalf of Auckland Council before the Auckland Unitary Plan Independent Hearings Panel, 2 March 2015. Available at: https://hearings.aupihp.govt.nz/hearings NZTA, 2017. Vehicle emissions prediction model [NZTA website]. Available at: https://nzta.govt.nz/roads-and-rail/highways-information-portal/technical- disciplines/air-quality-climate/planning-and-assessment/vehicle-emissions-prediction- model/ NZTA, 2018. Data & tools [NZTA website - Topic: Use; Subject: Vehicles] accessed 12 March 2018. Available at: https://nzta.govt.nz/planning-and-investment/learning- and-resources/transport-data/data-and-tools/ Peeters S, 2018. Auckland air emissions inventory 2016 – sea transport. Prepared by M&P Consulting Limited for Auckland Council. Auckland Council technical report, TR2018/017 Sridhar S and Metcalfe J, 2019. Auckland air emissions inventory 2016 – transport. Prepared by Emission Impossible Ltd for Auckland Council. Auckland Council technical report, TR2018/016 US EPA, 2000. National Air Pollutant Emission Trends, 1900-1998. Research Triangle Park, NC: Office of Air Quality Planning & Standards, US Environmental Protection Agency. Available at: http://www.epa.gov/ttnchie1/trends/trends98/trends98.pdf US EPA, 2006. AP42 Miscellaneous Sources, Unpaved roads (section 13.2.2). Research Triangle Park, NC: Office of Air Quality Planning & Standards, US Environmental Protection Agency
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Auckland air emissions inventory 2016 – transport (revised) 73 Appendix A Summary tables – annual emissions estimates
This appendix shows results for all years 2001 to 2040 for the Auckland region. Results for the Auckland Urban Airshed are included for 2016 only. The following notes apply to the regional summaries (Table A-1 to Table A-7):
2016 emissions assumed for lawn mowers and unsealed road dust for all years (2001-2040). 2016 emissions assumed for future projections of off-road vehicles and road laying (2026-2040). The following notes apply to the Auckland Urban Airshed summary (Table A-8):
Aircraft emissions are assumed to be within the airshed. Rail emissions assumed to be proportional to the length of track located within the airshed (19% of track line within the airshed). Off-road vehicle and lawnmower emissions assumed to be proportional to the area of the airshed relative to the region (the airshed covers 19 per cent of the regional area). Road dust from sealed roads assumed proportional to the length of road located within the airshed (64% of sealed roads are within the airshed).
Auckland air emissions inventory 2016 – transport (revised) 74 Table A-1: Annual emission estimates for the Auckland region in 2001
Source 2001 annual emissions (region) CO % of CO % of NOx % of SO % of % of PM % of VOC % of 2 2 PM (t/yr) 2.5 (t/yr) total (kT/yr) total (t/yr) total (t/yr) total 10 total (t/yr) total (t/yr) total Transport Motor vehicles 102,050 96% 2,524 80% 18,244 81% 2,149 95% 1,059 45% 1,014 77% 10,216 94% Aircraft 1,175 1% 417 13% 2,376 11% 111 5% 9 0% 9 1% 140 1% Railway locomotives 59 0% 13 0% 210 1% 0 0% 5 0% 4 0% 20 0% Off-road mobile vehicles 758 1% 199 6% 1,680 7% 1 0% 142 6% 131 10% 171 2% Lawn mowers 1,726 2% 7 0% 15 0% 0 0% 2 0% 2 0% 141 1% Road dust - sealed 92 4% 49 4%
Road dust - unsealed 1,024 44% 101 8%
Road laying 213 2%
Transport total 105,768 100% 3,160 100% 22,525 100% 2,262 100% 2,332 100% 1,310 100% 10,901 100%
Table A-2: Annual emission estimates for the Auckland region in 2006
Source 2006 annual emissions (region) CO % of CO % of NOx % of SO % of % of PM % of VOC % of 2 2 PM (t/yr) 2.5 (t/yr) total (kT/yr) total (t/yr) total (t/yr) total 10 total (t/yr) total (t/yr) total Transport Motor vehicles 84,144 95% 2,955 80% 15,570 75% 232 65% 937 41% 885 72% 7,308 90% Aircraft 1,278 1% 454 12% 2,586 12% 121 34% 10 0% 10 1% 152 2% Railway locomotives 90 0% 22 1% 326 2% 0 0% 8 0% 7 1% 33 0% Off-road mobile vehicles 1,002 1% 271 7% 2,266 11% 1 0% 188 8% 174 14% 224 3% Lawn mowers 1,726 2% 7 0% 15 0% 0 0% 2 0% 2 0% 141 2% Road dust - sealed 105 5% 57 5%
Road dust - unsealed 1,024 45% 101 8%
Road laying 228 3%
Transport total 88,241 100% 3,710 100% 20,763 100% 354 100% 2,275 100% 1,236 100% 8,087 100%
Auckland air emissions inventory 2016 – transport (revised) 75 Table A-3: Annual emission estimates for the Auckland region in 2011
Source 2011 annual emissions (region) % of CO % of NOx % of SO % of PM % of PM % of VOC % of CO (t/yr) 2 2 10 2.5 total (kT/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total Transport Motor vehicles 56,978 94% 2,964 81% 12,677 73% 71 37% 770 37% 718 69% 4,603 86% Aircraft 1,245 2% 442 12% 2,519 14% 118 62% 9 0% 9 1% 148 3% Railway locomotives 118 0% 30 1% 430 2% 0 0% 11 1% 10 1% 45 1% Off-road mobile vehicles 779 1% 209 6% 1,750 10% 1 1% 146 7% 135 13% 175 3% Lawn mowers 1,726 3% 7 0% 15 0% 0 0% 2 0% 2 0% 141 3% Road dust - sealed 109 5% 59 6%
Road dust - unsealed 1,024 49% 101 10%
Road laying 243 5%
Transport total 60,847 100% 3,652 100% 17,391 100% 190 100% 2,072 100% 1,034 100% 5,356 100%
Table A-4: Annual emission estimates for the Auckland region in 2016
Source 2016 annual emissions (region) % of CO % of NOx % of SO % of PM % of PM % of VOC % of CO (t/yr) 2 2 10 2.5 total (kT/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total Transport Motor vehicles 41,138 91% 3,186 81% 10,251 67% 73 37% 647 32% 588 63% 3,238 80% Aircraft 1,283 3% 455 12% 2,595 17% 121 62% 10 0% 10 1% 153 4% Railway locomotives 44 0% 8 0% 154 1% 0.1 0% 3 0% 3 0% 12 0% Off-road mobile vehicles 994 2% 274 7% 2,272 15% 1 1% 188 9% 173 18% 221 6% Lawn mowers 1,726 4% 7 0% 15 0% 0 0% 2 0% 2 0% 141 4% Road dust - sealed 118 6% 64 7%
Road dust - unsealed 1,024 51% 101 11%
Road laying 258 6%
Transport total 45,185 100% 3,930 100% 15,286 100% 196 100% 1,991 100% 940 100% 4,024 100%
Auckland air emissions inventory 2016 – transport (revised) 76 Table A-5: Annual emission projections for the Auckland region in 2026
Source 2026 annual emissions (region) % of CO % of NOx % of SO % of PM % of PM % of VOC % of CO (t/yr) 2 2 10 2.5 total (kT/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total Transport Motor vehicles 19,905 82% 3,400 80% 6,863 55% 20 12% 385 22% 314 46% 1,650 67% Aircraft 1,562 6% 555 13% 3,160 25% 148 87% 12 1% 12 2% 186 8% Railway locomotives 46 0% 8 0% 161 1% 0 0% 3 0% 3 0% 12 0% Off-road mobile vehicles 994 4% 274 6% 2,272 18% 1 1% 188 11% 173 25% 221 9% Lawn mowers 1,726 7% 7 0% 15 0% 0 0% 2 0% 2 0% 141 6% Road dust - sealed 143 8% 77 11%
Road dust - unsealed 1,024 58% 101 15%
Road laying 258 10%
Transport total 24,233 100% 4,243 100% 12,470 100% 169 100% 1,757 100% 682 100% 2,469 100%
Table A-6: Annual emission projections for the Auckland region in 2036
Source 2036 annual emissions (region) % of CO % of NOx % of SO % of PM % of PM % of VOC % of CO (t/yr) 2 2 10 2.5 total (kT/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total Transport Motor vehicles 12,244 73% 3,304 78% 5,363 46% 17 9% 315 18% 238 39% 1,060 55% Aircraft 1,842 11% 654 15% 3,726 32% 174 90% 14 1% 14 2% 220 11% Railway locomotives 52 0% 9 0% 181 2% 0 0% 3 0% 3 1% 14 1% Off-road mobile vehicles 994 6% 274 6% 2,272 20% 1 1% 188 11% 173 28% 221 12% Lawn mowers 1,726 10% 7 0% 15 0% 0 0% 2 0% 2 0% 141 7% Road dust - sealed 159 9% 86 14%
Road dust - unsealed 1,024 60% 101 16%
Road laying 258 13%
Transport total 16,857 100% 4,248 100% 11,556 100% 193 100% 1,706 100% 617 100% 1,914 100%
Auckland air emissions inventory 2016 – transport (revised) 77 Table A-7: Annual emission projections for the Auckland region in 2040
Source 2040 annual emissions (region) % of CO % of NOx % of SO % of PM % of PM % of VOC % of CO (t/yr) 2 2 10 2.5 total (kT/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total Transport Motor vehicles 12,201 72% 2,975 74% 5,225 44% 17 8% 306 18% 227 37% 1,040 54% Aircraft 2,065 12% 733 18% 4,178 35% 196 91% 16 1% 16 3% 246 13% Railway locomotives 54 0% 9 0% 190 2% 0 0% 4 0% 3 1% 15 1% Off-road mobile vehicles 994 6% 274 7% 2,272 19% 1 1% 188 11% 173 28% 221 12% Lawn mowers 1,726 10% 7 0% 15 0% 0 0% 2 0% 2 0% 141 7% Road dust - sealed 162 10% 89 15%
Road dust - unsealed 1,024 60% 101 16%
Road laying 258 13%
Transport total 17,041 100% 3,998 100% 11,880 100% 214 100% 1,701 100% 610 100% 1,921 100%
Table A-8: Annual emission estimates for the Auckland Urban Airshed in 2016
Source 2016 annual emissions (Auckland Urban Airshed) % of CO % of NOx % of SO % of PM % of PM % of VOC % of CO (t/yr) 2 2 10 2.5 total (kT/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total (t/yr) total Transport
Motor vehicles 28,693 95% 1,922 80% 7,024 71% 50 29% 439 71% 399 84% 2,270 91% Aircraft 1,283 4% 455 19% 2,595 26% 121 71% 10 2% 10 2% 153 6% Railway locomotives 9 0% 2 0% 30 0% 0 0% 1 0% 1 0% 2 0% Off-road mobile vehicles 115 0% 32 1% 263 3% 0 0% 22 4% 20 4% 26 1% Lawn mowers 200 1% 1 0% 2 0% 0 0% 0 0% 0 0% 16 1% Road dust - sealed 76 12% 41 9%
Road dust - unsealed 72 12% 7 1%
Road laying 30 1%
Transport total 30,299 100% 2,411 100% 9,913 100% 171 100% 619 100% 477 100% 2,497 100%
Auckland air emissions inventory 2016 – transport (revised) 78 Appendix B Daily motor vehicle emission estimates for 2016
This appendix shows the breakdown of estimated daily vehicle emissions for 2016 by vehicle type. The table also includes annual totals for petrol and diesel vehicles. Summary tables for other years are provided in the accompanying spreadsheets.
Auckland air emissions inventory 2016 – transport (revised) 79 Table B-1: Motor vehicle emissions for the Auckland region in 2016
2016 daily emissions PM PM % total PM PM PM 10 PM 2.5 Fuel Vehicle type Fuel VKT CO CO NOx NO SO VOC 10 2.5 10 brake 2.5 brake and VKT 2 2 2 total total exhaust exhaust consumpt’n and tyre tyre Million km/day kg/day t/day kg/day kg/day kg/day kg/day kg/day kg/day kg/day kg/day kg/day kg/day L/day
Car Petrol 24 67.0% 96,330 4,986 9,506 358 167 7,201 362 257 135 227 135 123 2,233,115 Light Petrol 1.2 3.3% 11,179 293 705 27 10 740 15 10 3 11 3 6 134,114 commercial Hybrid and Petrol 0.2 0.7% 9.0 24.6 3.0 0.1 0.4 0.2 2.4 1.3 0.0 2.4 0.0 1.3 10,741 electric Car Diesel 2.7 7.7% 543 537 1,839 625 3 133 273 261 247 26 247 14 203,925 Light Diesel 4.9 14.0% 1,926 1,262 5,137 1,672 8 311 641 619 593 47 593 26 477,715 commercial Heavy 3.5t ‐ Diesel 0.5 1.3% 274 156.68 1279 148 1 67 64 62 59 6 59 3 58,718 7.5t Heavy 7.5t ‐ Diesel 0.3 0.8% 316 136 999 117 1 59 51 49 47 3 47 2 50,863 12t Heavy 12t ‐ 15t Diesel 0.1 0.2% 79 39 276 33 0 21 14 13 13 1 13 1 14,571 Heavy 15t ‐ 20t Diesel 0.1 0.3% 132 74 492 59 0 34 24 23 22 2 22 1 27,736 Heavy 20t ‐ 25t Diesel 0.4 1.1% 470 279 1,983 241 2 98 94 91 88 5 88 3 104,553 Heavy 25t ‐ 30t Diesel 0.5 1.4% 528 368 2,215 266 2 87 95 92 88 7 88 4 137,565 Heavy >30t Diesel 0.6 1.8% 742 516 3,178 375 4 87 113 108 103 9 103 5 210,317 Buses Diesel 0.1 0.3% 178 58 469 55 0 35 26 26 25 1 25 1 21,917 Total (kg/day) 35 100% 112,708 8,728 28,084 3,977 200 8,872 1,772 1,612 1,423 349 1,423 188 3,685,850
2016 annual emissions
Annual Million km/yr t/yr kt/yr t/yr t/yr t/yr t/yr t/yr t/yr t/yr t/yr t/yr t/yr ML/yr
Total 12,829.8 41,138 3,186 10,251 1,452 73 3,238 647 588 520 127 520 69 1,345
Total petrol 9,115.9 71.1% 39,244 1,936 3,728 140 65 2,898 138 98 50 88 50 47 868
Total diesel 3,713.9 28.9% 1,894 1,250 6,522 1,311 8 340 509 491 469 40 469 21 477
Auckland air emissions inventory 2016 – transport (revised) 80
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