ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report (2019)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 44 6.0 Guidance to Use SAJF Impact Factors for Emissions Inventory and Dispersion Modeling at Airports 6.1 Guidance to Account for SAJF Impacts on Airport Emissions Inventory This section describes the method to adjust an airport emission inventory using the impact quantification factor functions to estimate the impact of SAJF blend percentages at airports. The pollutant-specific analysis described in section 4 show SAJF blend percentage as the only critical factor in determining the impact of use of SAJF at airports. Therefore, the impact of SAJF blend percentage on the airport emission inventory can be determined using the impact quantification functions to adjust the total baseline emission inventory as a post-process. The overview of the process to determine the impact of SAJF on airport emissions inventory is shown in Figure 13. STEP 1 – Determine SAJF blend percentage for which the impact needs to be estimated. STEP 2 – Compute the impact factors and associated uncertainties for each pollutant by plugging in SAJF blend percentages in the equations in Table 1. STEP 3 – Output the baseline emission inventory to three distinct datasets: 1) Total emission inventory for non-piston operations (step 3.1) 2) Total emission inventory for piston operations (step 3.2) 3) Total emission inventory for non-piston and piston combined (step 3.3). STEP 4 – Compute the total adjusted emission inventory for non-piston operations for each pollutant using total baseline emission inventory for non-piston operations (from step 3.1) and the impact factor computed is step 2, as shown below: 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦 ∗ (1+ 𝐼𝑚𝑝𝑎𝑐𝑡 𝐹𝑎𝑐𝑡𝑜𝑟 ) STEP 5 – Compute the total adjusted emission inventory as the sum of the total baseline emission inventory for piston operations (from step 3.2) and the total adjusted emission inventory for non-piston operations (from step 4). 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦+ 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦 STEP 6 – Compute the impact of SAJF on the total airport emissions inventory using the total adjusted emission inventory (from step 5) and the total baseline inventory emission (step 3.3) as shown below: 𝑆𝐴𝐽𝐹 𝐼𝑚𝑝𝑎𝑐𝑡 = 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐼𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦 − 1

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 45 Figure 13: Overview of the process to compute the impact of SAJF on airport emissions inventory 6.2 Instructions to Segregate Piston and Non-Piston Aircraft Operations in AEDT The impact quantification factors only apply to emissions from non-piston operations, therefore it is recommended to segregate non-piston operations and piston operations before modeling the airport inventory emissions. This section describes the process to segregate non-piston and piston operations into separate groups (i.e. cases as defined in AEDT) in the annualization defined in AEDT. The non-piston operations can be separated from piston operations by defining them under separate cases in the AEDT standard input file. Alternatively, the AEDT GUI can be used to segregate the piston and non-piston operations into separate groups as described below. Note: The instructions below are for AEDT version 2D. The process to create separate groups within the annualization using the AEDT GUI are as follows: 1. Go to the Operations tab and click on the Aircraft button in the Display ribbon to list all the operations defined in the study. Make sure while creating the operations list the “User ID” field has some identifier to tell the non-piston from piston aircraft. In the example below all the piston aircraft have “User ID” starting with a “P” and non-piston with “NP”.

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 46 Figure 14: Example of an operations list with piston aircraft have “User ID” starting with a “P” and non-piston with “NP” 2. Click on Annualizations button in the Display ribbon and click on the New button in the Annualization Actions button 3. Select checkbox “Add new aircraft operation group(s)” and click next. The next page will show the list available operations and option to add new operation groups. 4. Type the name of the operations group and click add. 5. Use the “User ID” filter to select all the operations to be added to the operations group and click next. In the example below, non-piston aircraft operations are assigned to a user defined group named Ops_nonpiston using the following steps: First a new operation group called Ops_nonpiston is created, next the “User ID” filter is opened and using the criterion “Starts with” set to “NP” all the non-piston aircraft operations are filtered. Next all the filtered operations are moved to the Ops_nonpiston operation group by selecting and dragging the operations to the operation group as shown below. Note: To select all the filtered operations, select any one operation and then use “Ctrl+A” option.

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 47 Figure 15: Example showing the use of “User ID” filter to select and group piston and non-piston aircraft operations Figure 16: Example showing method to drag selected operations to the corresponding operations group

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 48 6. On the next page move the operations groups to “Root” in the “Assigned annualization window” using the select and drag feature and click next. 7. Finally set the processing options or choose the default options and click “Create” to create the annualization. 8. Create the emissions metric using the annualization created using the process described above the run the metric. Figure 17: Example showing method to drag operations group to the Root annualization

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 49 Figure 18: Screenshot showing the annualization created Once the metric is run, the user can view the results in the Reports tab by selecting the metric and then clicking on Emissions and Fuel button in the Reports ribbon. The user can generate the emission inventory report for each aircraft operations group (piston and non-piston) by selecting the group using the drop- down option show in the figure below and save the results to .csv file, which can then be processed using the approach described in the previous section to compute the adjusted emission inventory. Figure 19: Example showing method to generate emission inventory report for each operations group

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 50 Figure 20: Example showing results for piston aircraft operation group Figure 21: Example showing results for non-piston aircraft operation group 6.3 Guidance to Account for Impact of SAJF on Emission Dispersion at Airports The SAJF impact factors apply only to non-piston operations and in case of emission inventory, the SAJF impact factors can be applied to non-piston emissions as a post-process. As described in the previous section, the emission inventory can be conducted with piston and non-piston operations as separate cases

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 51 in the study scenario, which then calculates the total baseline emissions inventory for each case separately to apply the post-process methodology. Unlike emissions inventory, the emissions dispersion, which is expressed as pollutant concentration (µg/m³) at the receptors, is computed for all the operations in the study scenario and therefore does not produce separate outputs for piston and non-piston operations. The dispersion analysis for piston and non-piston operations can be modeled as sperate scenarios. However, emission dispersion from separate scenarios cannot always be combined, as emission dispersion is sensitive to operations departure times, the corresponding weather, and the use of the delay and sequencing model. Therefore, for airports with piston and non-piston operations, the post-processing methodology may not yield accurate estimates for impact of SAJF on emission dispersion. The emissions dispersion tools currently do not model dispersion for nvPM. A method to model nvPM dispersion is proposed, which involves calculating the ratio of the nvPM to PM in the total emission inventory and then adjusting the PM dispersion concentration as a post-process to obtain the emissions dispersion concentration for nvPM. This section describes methods to account for impact of SAJF on emissions dispersion at 1) airports that only have non-piston operations and 2) airports that have mix of pistons and non-piston operations. 6.3.1 Guidance to Account for Impact of SAJF on Emission Dispersion at Airports with Only Non- Piston Operations For airports with only non-piston operations, the impact of SAJF on emissions dispersion can be determined as post-process of the baseline emissions dispersion concentrations at the receptor as follows: STEP 1 – Determine SAJF blend percentage for which the impact needs to be estimated. STEP 2 – Compute the impact factors and associated uncertainties for each pollutant by plugging in SAJF blend percentages in the equations in Table 1. STEP 3 – Model and output baseline emissions dispersion concentrations. STEP 4 – Compute the adjusted emissions dispersion concentration at each receptor using the baseline emissions dispersion concentrations and the impact factor computed is step 2, as shown below: 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 ∗ (1+ 𝐼𝑚𝑝𝑎𝑐𝑡 𝐹𝑎𝑐𝑡𝑜𝑟 ) For nvPM, before applying the above formula, compute the baseline emissions dispersion concentration at each receptor using the ratio of the total nvPM and PM inventory emissions as follows: 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 ∗ 𝑇𝑜𝑡𝑎𝑙 𝑛𝑣𝑃𝑀 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠𝑇𝑜𝑡𝑎𝑙 𝑃𝑀 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 52 STEP 5 – Compute the impact of SAJF on the total airport emissions dispersion at each receptor using the total adjusted emissions dispersion and the total baseline emissions dispersion, as shown below: 𝑆𝐴𝐽𝐹 𝐼𝑚𝑝𝑎𝑐𝑡 = 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 − 1 6.3.2 Guidance to Account for Impact of SAJF on Emission Dispersion at Airports with Piston and Non-Piston Operations There are two potential methods to account for impact of SAJF in emissions dispersion calculations at airports with both piston and non-piston operations. The first is the post-process method which involves the following steps: STEP 1 – Determine SAJF blend percentage for which the impact needs to be estimated. STEP 2 – Compute the impact factors and associated uncertainties for each pollutant by plugging in SAJF blend percentages in the equations in Table 1. STEP 3 – Group piston and non-piston operations into separate study scenarios. STEP 4 – Model and output baseline emissions dispersion concentrations for the two scenarios (i.e., piston and non-piston). STEP 5 – Compute the adjusted emissions dispersion concentration at each receptor for non-piston operations using the corresponding baseline emissions dispersion concentrations and the impact factor computed in step 2, as shown below: 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 ∗ (1+ 𝐼𝑚𝑝𝑎𝑐𝑡 𝐹𝑎𝑐𝑡𝑜𝑟 ) For nvPM, before applying the above formula, compute the baseline emissions dispersion concentration at each receptor using the ratio of the total nvPM and PM inventory emissions as follows: 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛_𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 ∗ 𝑇𝑜𝑡𝑎𝑙 𝑛𝑣𝑃𝑀 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠𝑇𝑜𝑡𝑎𝑙 𝑃𝑀 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 STEP 6 – Compute the total adjusted emissions dispersion concentration at the receptors as the sum of the baseline emissions dispersion concentrations for piston operations and the adjusted emissions dispersion concentration for non-piston operations (from step 4). 𝑇𝑜𝑡𝑎𝑙 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛+ 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝑁𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 53 STEP 7 – Compute the total baseline emissions dispersion concentration at the receptors as the sum of the baseline emissions dispersion concentrations for piston operations and the baseline emissions dispersion concentration for non-piston operations (from step 4). 𝑇𝑜𝑡𝑎𝑙 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛= 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑃𝑖𝑠𝑡𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛+ 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑁𝑜𝑛 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 STEP 8 – Compute the impact of SAJF on the airport emissions dispersion at each receptor using the total adjusted emissions dispersion and the total baseline emissions dispersion as shown below: 𝑆𝐴𝐽𝐹 𝐼𝑚𝑝𝑎𝑐𝑡 = 𝑇𝑜𝑡𝑎𝑙 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛𝑇𝑜𝑡𝑎𝑙 𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 − 1 As described previously, the post-process methodology may not yield accurate estimates for impact of SAJF on emissions dispersion at airports with both piston and non-piston operations, as emissions dispersion from separate scenarios cannot always be combined; emissions dispersion is sensitive to operations departure times, corresponding weather, and use of the delay and sequencing model. To compute more accurate estimates of SAJF impacts on emissions dispersion at airport, a second method is proposed, which involves generating a new list of aircraft with the emissions indices (EIs) adjusted to account for the SAJF impact factors. The method involves the following steps: STEP 1 – Determine SAJF blend percentage for which the impact needs to be estimated. STEP 2 – Compute the impact factors and associated uncertainties for each pollutant by plugging in SAJF blend percentages in the equations in Table 1. STEP 3 – In the modeling tool, create new aircraft types for each of the aircraft types in the baseline scenario and modify the EIs for the landing takeoff (LTO) modes using the impact factors computed in step 2. 𝐴𝑑𝑗𝑢𝑠𝑡𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐼𝑛𝑑𝑒𝑥 , = 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐼𝑛𝑑𝑒𝑥 . ∗ (1 + 𝐼𝑚𝑝𝑎𝑐𝑡 𝐹𝑎𝑐𝑡𝑜𝑟 ) STEP 4 – Create two scenarios, the baseline scenario with the original the piston and non-piston aircraft, and the modified scenario with the original piston and the modified non-piston aircraft. STEP 5 – Model and output emissions dispersion concentrations for the two scenarios. STEP 6 – Compute the impact of SAJF on the total airport emissions dispersion at each receptor using the emissions dispersion from the modified scenario and the emissions dispersion from the baseline scenario as shown below:

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 54 𝑆𝐴𝐽𝐹 𝐼𝑚𝑝𝑎𝑐𝑡 = 𝑀𝑜𝑑𝑖𝑓𝑖𝑒𝑑 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛𝐵𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝐷𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 − 1 Note: Although SAJF use impacts nvPM emissions, the impact on nvPM emissions dispersion concentrations cannot be computed using the method described above. As mentioned before, the emissions dispersion tool only model emissions dispersion for total PM (10 and 2.5), which constitutes volatile PM components from fuel sulfur content (PMSO) and hydrocarbon (fuel) organics (PMFO) and nvPM. The EI for these pollutants are computed using First Order Approximation 3.0 Method (FOA 3.0) which is hard-coded in the emissions modeling tools and cannot be modified by the user.